Cellulose building insulation:

This article illustrates and describes the properties of cellulose building insulation materials.

We added these examples because of frequent questions about these materials. This document assists building buyers, owners or inspectors who need to identify building insulation materials and also people who need to recognize both asbestos materials (or probable asbestos) in buildings as well as materials unlikely to contain asbestos - all by simple visual inspection.

Cellulose building insulation identification guide

Modern cellulose building insulation is basically chopped newsprint, usually treated with a fire retardant chemical. As you can see in the photos above, it looks like fluffy gray papery material. The lighter colored chips may be wood fragments that have been added to this mix.

Installed at times by pouring but usually by blowing into building attic floors or into building wall cavities, cellulose insulation is composed of 75 to 85% recycled paper fibres or fragments to which is added a fire-retardant, often boric acid and ammonium sulphate. Cellulose building insulation uses more recycled material than other building insulating products.

Article Contents:

• DETAILS HELP IDENTIFY CELLULOSE INSULATION
• HOW TO INSPECT CELLULOSE INSULATION for DEFECTS
• PROS & CONS OF CELLULOSE BUILDING INSULATION
• R VALUES & EFFECTIVENESS OF CELLULOSE BUILDING INSULATION
• MOLD RESISTANCE OF CELLULOSE BUILDING INSULATION
• ODOR PROPERTIES OF CELLULOSE BUILDING INSULATION
• SETTLEMENT OR VOID PROBLEMS IN INSULATION
• MANUFACTURERS OF CELLULOSE INSULATION

Visual Details Help Identify Loose-Fill Cellulose Insulation

Cellulose insulation is usually blown in to building cavities as an insulation retrofit or into attics where it is being added or where access is physically difficult.

Cellulose building insulation has been used in buildings since or before 1937 and continues to be installed in buildings today in the U.S.

Cellulose insulation produced by some manufacturers is a mixture of chopped paper and wood fibers (sawdust).

Above, a close-up look at cellulose insulation will often show small fragments of paper on which you may make out printed characters or partial characters (photo above, red arrow). Or you may see small fragments of paper of different colors (photo below).

These details can help identify cellulose insulation and will distinguish it from just about any other building insulation product. [Click to enlarge any image]

Usually we can readily identify cellulose building insulation by simple visual inspection - "by eye" as shown in the photos above.

If you are uncertain about whether an insulating material is loose-fill, blown-in, or wet-packed cellulose, try looking at a sample with a hand-held lens magnifying glass.

Or for absolute identification of cellulose and its components, see

CELLULOSE INSULATION UNDER the MICROSCOPE - microscopic examination of insulation materials, or simple use of a magnifying glass to examine cellulose insulation for identification & properties.

How to Inspect Cellulose Insulation for Defects

Don't cut a big hole to look for blown in cellulose insulation - as you can see in this photo, it may simply fall out.

If you inspect an older building's basement or crawl space, it may be easy to see if cellulose insulation has been blown into the building's walls.

Check at the building's sills atop the foundation walls.

Often openings in building walls permit blown-in cellulose to fall onto the top of the sill as you can see in our photo at left.

Pros and Cons of Cellulose Building Insulation

The following is an expanded/updated online version of an original article by Steven Bliss, published in Solar Age magazine, cited at the end of this page.

Question: How does Cellulose Insulation Stack Up Against Fiberglass or Rockwool Insulation?

I plan to retrofit 7 inches of blown insulation over the top of 6 inches of existing fiberglass insulation, and I would like to use blown-in cellulose.

How does cellulose insulation stack up against fiberglass or rockwool with respect to

1. R-value of cellulose insulation 
   
   compared with fiberglass or mineral wool (rock wool) insulation
2. Moisture absorption of cellulose insulation 
   
   compared with fiberglass or mineral wool (rock wool) insulation
3. Attraction to (resistance to) nesting rodents: cellulose insulation 
   
   compared with fiberglass or mineral wool (rock wool) insulation
4. Fire protection (fire resistance) -
   
   of cellulose insulation compared with fiberglass or mineral wool (rock wool) insulation.

Thanks - David Stingle, Black Creek WI

Below we add additional insulation property questions and answers:

• Mold resistance of cellulose insulation, details are
  
  at CELLULOSE INSULATION MOLD RESISTANCE
• Insulation settlement and compaction, details are
  
  at RETROFIT INSULATION SETTLEMENT, VOIDS
• And at BLOWN-IN INSULATION we also discuss insulation settlement in retrofit jobs and we calculate the potential impact on wall R-value.

Answer: R-vale per inch of loosefill cellulose insulation varies

The R-vale per inch of loosefill insulation varies depending on its installed density and product characteristics. For that reason, the most reliable way to buy loose-fill insulation is to specify the R-value - not the thickness - and install the correct number of bags per square foot, following the loose-fill or blown-in insulation coverage chart printed on all insulation bags.

The insulation chart also shows a minimum insulation thickness necessary to guarantee the desired R-value.

The U.S. Federal Trade Commission (FTC) requires insulation manufacturers to make available to consumers an information sheet explaining this system.

Cellulose insulation yields R-3.1 to R-3.7 per inch, compared to R-2.2 to R-2.9 per inch for blown in or loose-fill fiberglass and rockwool insulation. In general, you should compare products on the basis of cost per R-value per square foot.

Moisture absorption of cellulose insulation:

Of the three insulations you named: blown-in or loose-fill cellulose, fiberglass, or rockwool, only cellulose will absorb moisture, but this is only a problem if it gets drenched, such as by roof leaks into an attic or building wall. The other two insulations will hold moisture only on their glass or mineral fiber surfaces.

Fire resistance of cellulose insulation:

Of the three insulation products we are discussing, only cellulose is potentially flammable if its fire retardant loses effectiveness over time (as some suspect of the dry-applied fire-retardants). Studies in the mid 1980's of the reliability of fire retardance of cellulose insulation over time were inconclusive.

See CELLULOSE INSULATION FIRE RESISTANCE for details.

As for rodent resistance of cellulose insulation,

we (DJF) have observed that rodents are happy tunneling in just about any soft insulating material, but we have also observed that a different sort of pest, mold, is not generally found in cellulose insulation. We (DF) believe based on our own field and lab investigations that the fire retardant chemicals used to treat cellulose insulation appear to also resist mold growth.

The question-and-answer article above and also appearing

at CELLULOSE INSULATION PROS & CONS, quotes from, updates, and comments from an original article from Solar Age Magazine and written by Steven Bliss.

What are the R Values and Effectiveness of Cellulose Building Insulation?

The thermal resistance or heat-loss resistance of cellulose insulation sold by Pal-O-Pak Insulation company, for a 10-inch depth, was reported as 0.635 per square meter. The product heat resistance ranged (by thickness) from 0.004 to 1.602 m²· K· W^-1. Modern blown-in cellulose building insulation has an R-value of about 3.70 per inch.

Our photo (left) of cellulose insulation sprayed over a suspended ceiling shows an area we were investigating for mold on the upper or hidden side of the suspended ceiling tiles (none was visible). We brushed back the cellulose insulation to check the ceiling surface. But you can also see that this insulation plan was not the best. About R7.

Less than three inches of insulation had been added, and working on wiring or piping in the ceiling area means removing one of these ceiling tiles and dropping cellulose insulation into the occupied space - a bit of a mess.

What these data and most reports of insulation products' resistance to heat loss do not include is the large impact on building heat loss or the degree of care with which any insulating product has been installed.

Gaps between insulating materials and building surfaces can permit drafts which can overcome otherwise high "R" values that may be associated with the insulating material. (Just imagine a well-insulated home in the dead of winter but with a few windows open.)

Insulating materials that by their physical nature tend to fill in cracks and gaps without much human effort, such as blown-in products or foamed products, are likely to produce fewer air leaks and thus may be expected to improve the economy of heating or cooling a building when compared with construction where diligence was not a watchword.

To compare insulating material R-values see

our INSULATION R-VALUES & PROPERTIES

Question: changing estimates of R-values for cellulose insulation

2016/08/15 Z Wilfre said:

I have had about 75 bags of cellulose insulation, 30 pounds each, stored since 1989 in my summer residence. Now I am retiring and want to blow them into the attic. The information on the old bags show that a R32 is 8.8 inches settled, with a density of 1.88 per square foot, installed. 1000 sq. ft. would require 62.6 bags (30 lbs. each) net.

Since the place is large, I went to Menards website which shows that R30 to be 8.6 inches settled and require 46 bags (18.1 lbs each) with a density of 8.78 lbs per sq. ft. installed. This is about half the density of the 1989 cellulose that I already have.

My questions: What has changed? Is the cellulose produced today approximately twice as efficient? Has the measurement of "R" values changed? Is the product in the old 30 lbs bags somehow not as "fluffy" or does a newer blower chop it up better and make it a better insulator.

Reply:

I suspect that different people are making the same calculation with perhaps very slight changes in product rating, test results, or other factors. I'd ignore it. After all, real on-site variations such as how densely or loosely you blow the insulation will overwhelm the slight R difference in the two theoretical claims.

Z Wilfre said:

Perhaps all my information was confusing, I think I got the Menards density wrong by a factor of 10. (should be 0.878 lbs/ sq ft. for R30)

But a simpler calculation shows that the old cellulose gives 0.059 lbs/sq ft per R. Menards gives 0.029 lbs/sq ft per R. This is not "slight". This is double. I take it that in your experience the "lbs/sq ft per R" has not changed with time. I guess I will experiment a bit and see if I can get the old cellulose to be as effective as the Menards cellulose. Which would save me about $300. I'll let you know. Thanks for your response.

(mod) said:

To be clear and candid, my search didn't find a list of historical R-values for loose-fill cellulose. I don't think we can reliably compare R-values from different eras without first knowing exactly how the R-value was determined.

Historically those were "measured" in the field by obtaining U values and converting them to R. (See DEFINITION of HEATING & COOLING TERMS)

Briefly R is heat transfer resistance while U is the more easily measured heat-conductance.

A problem with that approach is that it doesn't account for variation in how the insulation was installed: how loose, how tightly packed, or perhaps other factors affecting the measured wall area heat transmission.

A simple change in test conditions, such as starting with different indoor and outdoor temperatures will change the measurement (heat transfer rate is greater when there is greater difference between the two areas). 15K is the ideal difference when making measurements, and other factors such as solar radiation, wind, moisture and humidity, infiltration all need to be held constant.

There might also differences in the cellulose application method: loose-fill dry-spray vs wet-spray methods. And in walls, settlement vs. when measurements are made would be a factor.

R-value measurement, claims, and advertising remain controversial in the insulation industry. Typical R-values claimed for cellulose insulation by either method are R 3 to 3.8 per inch.

For other readers,

• Menard's Insulmax cellulose insulation (dry applied - no water) specifications are at hw.menardc.com/main/items/media/GREEN083/Prod_Tech_Spec/InsulmaxCoverageChart11-22-2014.pdf

There, a 3.5" thickness (presumably in a wall and without accounting for settlement or voids) of loose fill cellulose = R13. That's an R of 3.71 / inch and right in line with industry claims.

All of the R-value or even density per "square foot" claims are to me confusing since when a homeowner is installing cellulose insulation she is not going to have any idea the density at which it is being applied, nor the thickness of "a square foot" since by definition squares omit a thickness dimension.

2016/08/19 Z Wilfre said:

I did find a history of cellulose insulation. So it appears that my old cellulose won't perform as well as the new cellulose for the same density. The web link is: www.ecia.eu.com/support/content/history-of-cellulose-insulation

"Material density of loose-fill cellulose is one example of the progress that has occurred. As recently as 1980 the settled density of a typical cellulose product was over 42kg/m3. By the mid-80s average density had decreased to about 40kg/m3. A couple years later 38kg/m3 was common. This was done by improving and refining production technology that had been used for 40 years or more.

At the end of the 1980s new manufacturing technologies became available, and the density of cellulose insulation dropped suddenly by about a 2-5kg/m3. Today the average settled density of cellulose is about 30-35kg/m3"

" Cellulose insulation is now produced on very good technology based on fiberization systems, which maximize fiber separation. These attenuated, long and slender fibers are consistent, uniform and offer much better comfort during application."

Moderator said:

ZW thanks; we'll research and add that information.

The source you cite is a recently formed insulation industry association, the European Cellulose Insulation Association, Website: www.ecia.eu.com/, Administrator Lucia Gross lucia.gross@ecia.eu.com.

In North America, for the U.S. see CIMA, the Cellulose Insulation Manufacturers Association, 136 South Keowee St., Dayton OH 45402, Tel: 937-222-2462. CIMA provides a helpful document listing cellulose insulation building codes, regulations, specifications and voluntary standards, CIMA Technical Bulletin #1, [PDF] at inspectapedia.com/insulation/Cellulose_Insulation_CIMA.pdf

Certainly casual observation of cellulose in older vs newer homes shows that newer cellulose *looks* more finely fluffed as individual particles.

Still I'd consider these average density numbers and variations in rated R-value and weight as underlying theory rather than as accurate predictors of the insulation performance in a given installation.

Not included in the ECIA's otherwise helpful description of the properties of cellulose insulation, and pertaining to all insulation products, I emphasize that having inspected many cellulose insulated homes, including opening or disassembling older homes containing various qualities and types of insulating materials, I almost always find installation variations whose effect on the building's overall heat loss or heat gain will swamp the underlying theory.

A few missed cavities or over-pumped overly dense insulating material along a wall can add up to a heat loss effect similar to leaving a window open. What this means to us who care about a home's thermal performance is that attention to detail during an insulation job is important.

What is the Mold Resistance of Cellulose Building Insulation?

We suspect that building cavities insulated with fire-retardant treated cellulose insulation are a bit more resistant to mold growth than cavities insulated with fiberglass, cotton, or some other materials.

Our hypothesis is that the fire-retardant chemicals happen to also discourage fungal growth.

Details about mold resistance of cellulose building insulation: field inspection & lab testing

Mold resistance of cellulose insulation: we (DJF) add to this list of properties of cellulose insulation our field and laboratory observation that cellulose insulation appears to be highly resistant to mold growth and somewhat resistant to insect activity compared with fiberglass and mineral fiber insulation.

We have inspected buildings at which cellulose insulation in walls or attics has been actually wet (from building leaks and from fighting building fires).

Testing cellulose insulation for mold contamination included both analysis of bulk samples from buildings where the insulation appeared undisturbed and others where it had been soaked.

We examined the cellulose insulation microscopically in our forensic laboratory, at low magnification for evidence of visible mold contamination on the surface of the cellulose fragments, and at high power magnification up to 1200x for individual mold spores.

We also collected vacuum samples of cellulose wall insulation in the same buildings in order to more readily separate the larger cellulose insulation fragments from the generally smaller, lighter mold spores that might be present.

Testing in our laboratory did not in any case detect meaningful mold contamination nor mold growth in the cellulose.

We believe that the fire retardant chemicals used to treat cellulose insulation probably also imparts mold growth resistance.

See  FIBERGLASS INSULATION MOLD for examples of mold contamination in building insulation.

Odor Properties of Cellulose Building Insulation

According to Deborah Falkow, owner of MetroNY Insulation, both National Fiber's Cel-Pak and Nu-Wool cellulose insulations are "all-borate formulations" (for fire, pest and mold resistance).

Borate is an odorless mineral that doesn't outgas, which is a fancy way to say that National Fiber's cellulose products don't produce funny smells.

But some cellulose building insulations may produce a funny odor, especially right after insulation. Ms. Falkow continues: "Some cellulose manufacturers use an ammonium sulfate/borate mix. That can produce objectionable odors, under the right conditions.

Question: cellulose insulation odor complaints, diagnosis, solutions

(May 13, 2015) Cellulose Odors said:

I built a new home in New England and moved in last August. We noticed over the winter, a slight odor in our attic which is a walk in attic, located off of the master bedroom closet. That odor has drastically increased as the weather becomes warmer, its overwhelming.

What could the odor be? We are worried it could be toxic and want to understand what to do to resolve. We have contacted our building and insulation provider but I'd like to have my facts ready for that discussion and would appreciate any insight folks can offer.

(Jan 20, 2016) joseph fish said:

I have this house that has blown insulation in the floors and drywall holding it up. It's 10" thick and notice smell and mold issues in the house.I been living here 3 yrs. now and think I need to get it out.

Prior to living here the basement was cealed up with foam sheets on center block foundation and 10" out with paneling, had no air flow at all and electric heating. I took out all the paneling and insulation sheets but the insulation in the flooring is still there. Issue is smell and mold.

Reply:

Cell

Thanks for the question: but from just this text no sensible building consultant would volunteer what the odor is or even is likely to be - we have little cellulose insulation odor data except for Falkow's comments above and the research on odors in cellulose insulation that I cite below.

I don't know if it's a coating, a dead animal, something spilled, a water leak that got something wet, or what. Your comment is on a cellulose insulation page. If your insulation is cellulose, that material is rather mold resistant. If a leak got drywall from a ceiling below wet or wet something else there could be a mold problem.

That's already more arm-waving than fits the facts. All I can say from the facts of your note is that often an existing problem smells worse when things warm up.

I'd look for candidates: spills, leaks, animals, materials that maybe got wet.

Mr. Fish

Cellulose insulation is not particularly conducive to mold growth, but there could be mold on the cavity side of drywall if it was wet. I'd make some test cuts to inspect the most suspect areas first.

ASTM C-739 provides tests for R-value, odor, moisture vapor accordance with ASTM Standard C-1015, Standard Practice for Installation of Cellulosic and Mineral Insulation.

Research on odors in cellulose building insulation

• Anderson, Robert W., and William Freischel. "Evaluation of the Proposed Smoldering Testing Methodology for Cellulosic Insulation." Journal of Building Physics 2, no. 1 (1978): 7-23.
• CIMA. "CELLULOSE INSULATION, CODES, REGULATIONS & SPECIFICATIONS, CIMA Technical Bulletin #1.", [PDF] The Cellulose Insulation Manufacturers Association 136 South Keowee Street Dayton, OH 45402 (937) 222-2462, Retrieved 2016/08/16, original source: http://blevinsweatherization.com/wp/wp-content/uploads/2010/08/INSULATIONACCESS-0270398.TDS_.pdf
• Ezeonu, I. M., J. A. Noble, R. B. Simmons, D. L. Price, S. A. Crow, and D. G. Ahearn. "Effect of relative humidity on fungal colonization of fiberglass insulation." Applied and Environmental Microbiology 60, no. 6 (1994): 2149-2151.
• Lstiburek, Joseph, BASEMENT INSULATION SYSTEMS [PDF] U.S. Department of Energy & Renewable Energy, Building Technologies Program, Retrieved 2016/08/16
• Sprague, Robert W., and Kelvin K. Shen. "The use of boron products in cellulose insulation." Journal of Building Physics 2, no. 4 (1979): 161-174.
• Yost, Nathan, and Joseph Lstiburek. "Basement insulation systems." Building Science Corporation online, www. buildingscience. com/resources/foundations/basement_insulati on_systems. pdf, dated July (2002).

Settlement or Void Problems with Various Building Insulation Products

Insulation settlement and compaction: the effectiveness and R-value of any loose fill insulation product (cellulose, chopped fiberglass, mineral wool, rock wool, vermiculite) that is poured or blown into building wall cavities, attic floors, or cathedral ceilings is at the mercy of the workmanship of the installer.

Deborah Falkow, owner of MetroNY Insulation, writes that the worry about cellulose insulation settlement in buildings is a myth. "Dense-packed cellulose doesn't settle, because it can't.", she writes. "It's installed at twice its settled density, which means that it's under slight pressure in the wall or ceiling cavity."

At BLOWN-IN INSULATION we also discuss insulation settlement in retrofit jobs and we calculate the potential impact on wall R-value.

Insulation Voids: Causes & Types

If an insulation retrofit job omits certain building areas such as the stud bay below windows, cavities above or below older framed buildings that use diagonal corner bracing, or cathedral ceilings built with fire blocking, there may be voids in the insulation blanket.

In field inspection, we have not observed insulation voids that appeared to be due to the material rather than workmanship of the installer, with the exceptions of:

• UFFI, Urea Formaldehyde Foam Insulation:
  
  foam shrinkage can leave significant gaps at the top and sides of UFFI that was injected into building wall cavities.
  
  See UREA FORMALDEHYDE FOAM INSULATION, UFFI.
• Fiberglass insulation:
  
  custom-cut fiberglass batts that are retrofitted to older frame buildings whose framing members were not placed on uniformly spaced centers may be poorly fit if workmanship is not careful.
  
  Also see : INSULATION AIR & HEAT LEAKS
• Foam board insulation:
  
  custom cut foam insulating board sections that are retrofitted to older frame buildings whose framing members were not placed on uniformly spaced centers may be poorly fit if workmanship is not careful.
• Poured insulation or blown-in attic floor insulation:
  
  is sometimes distributed unevenly in insulation retrofit jobs leaving areas of thin or even no insulation, especially in hard to reach areas, if workmanship is not careful.
• Also see AIR LEAK DETECTION TOOLS

Other Voids in Blown-in Building Wall or Ceiling Insulation

As discussed at BLOWN-IN INSULATION:

Watch out: in some blown-in building insulation retrofit projects, we have occasionally found significant insulation voids where the installer was careless, or where the installer did not anticipate blockages in the wall cavity formed by diagonal bracing [image] or fire blocking. An infra-red or thermal scan of a heated building during cold weather will make such insulation voids obvious.

We did indeed observe significant shrinkage, not settlement, in UFFI blown-in insulation in some homes insulated with that product in the 1970's, particularly if the product was not properly mixed in the first place.

See UREA FORMALDEHYDE FOAM INSULATION, UFFI

Watch out: other insulation properties such as air flow resistance and moisture resistance may be very important in some cases, such as choosing an insulation to use in or over a crawl space that may be damp, or against basement foundation walls.

See INSULATION INSPECTION & IMPROVEMENT

and FIBERGLASS INSULATION MOLD for examples.

Details about the R-values and other properties of various insulation products can be found in our Insulation Table

at INSULATION R-VALUES & PROPERTIES.

Manufacturers of Cellulose Insulation & Cellulose Insulation Information, Codes, Standards

Cellulose insulation manufacturers registered by NIST

• National Cellulose Corp.,
• National Fiber Corp. (Cel-Pak & Nu-Wool)
• U.S. Insulation Sales Corp.,
• Pal-O-Pak Insulation Company (aka National Cooperatives, Inc.),
• United Materials Corporation, and
• Insul-Wool Insulation Corporation.

In our building insulation articles, we provide photographs and descriptive text for various kinds of building insulation along with description of the characteristics of each material.

Cellulose Insulation History, Properties, Codes, Standards

• Original article, Steven Bliss , Q&A on Cellulose Insulation, Solar Age Magazine, December 1985/January 1986, adapted and updated for InspectAPedia.com December 2010 - April 2022.

• Also see References or Citations at the end of this article
• Applegate Insulation, "Standard Practice for Installing Cellulose Building Insulation", [PDF] Applegate Insulation HQ 1000 Highview Drive Webberville, MI 48892 800-627-7536 - retrieved 2016/08/19, original source: Standard Practice for Installing Cellulose Building Insulation
  Excerpt: This recommended practice covers the application of cellulosic thermal insulation in attics, sidewall cavities and between floors of single & multi family dwellings and other buildings by means of pneumatic equipment.
• ASTM: American Society for Testing and Materials, Annual Book of ASTM Standards Volume 4.06 Thermal Insulation; Environmental Acoustics, ASTM, Philadelphia
• ASTM C1338-14 Standard Test Method for Determining Fungi Resistance of Insulation Materials and Facings
• ASTM Standards C-168 Standard Terminology Relating to Thermal Insulating Materials
• ASTM Standards C-739 Standard Specification for Cellulosic Fiber (Wood Base) Loose Fill Thermal Insulation
• ASTM Standards C-755 Standard Practice for Selection of Vapor retarders for Thermal Insulation C-1149 Standard Specification for Self-Supported Spray Applied Cellulosic Thermal / Acoustical Insulation
• ASTM Standards C-1015 Standard Practice for Installation of Cellulosic and Mineral Fiber Loose-Fill Thermal Insulation
• ASTM Standards E-241 Standard Guide for Limiting Water-Induced Damage to Buildings
• ASTM, Blown Cellulose Fiber Thermal Insulations: Part 1—Density of Cellulose Fiber Thermal Insulation in Horizontal Applications, 1978 -- STP660STP35738S
  Abstract:
  This paper presents results of a study with the following objectives:
  
  1. Determine the effects of transport and placement conditions on the initial density of the insulation.
  
  2. Establish a standardized method for producing specimens of blown cellulose fiber insulations.
  
  3. Investigate the factors that cause the material to settle after placement.
  
  4. Establish a standardized method to produce settlement in the specimens comparable with those found in field studies.
  
  A method recommended for producing settlement in the specimens consists of two procedures, one simulating settlement by impact produced on the standardized containers, and the other causing settlement under climatic cycling of the material. The purpose of this recommended practice is to inform installers, system designers and consumers of acceptable procedures to ensure proper installation. It also identifies some of the precautions which need to be taken.
• BALSAM WOOL vs CELLULOSE INSULATION - a comparison
• Cellulose Insulation Manufacturers Association of Canada, Association Canadienne des Fabricants d'Isolant de Cellulose, 38-10, Place du Commerce, #255, Îles des Soeurs Montreal, QC H3E 1T8 01-800-515-1024 Fax/Télécopieur: 937-222-5794 cimac@cellulose.org Website: http://www.cellulose.ca/
• Cellulose Insulation Manufacturers Association (CIMA), 136 South Keowee St., Dayton OH 45402, Tel: 888-881-2462 Email: info@cellulose.org Website: cellulose.org/
  CIMA provides several helpful documents including
  • CELLULOSE INSULATION BUILDING CODES, REGULATIONS, SPECIFICATIONS AND VOLUNTARY STANDARDS, CIMA Technical Bulletin #1, [PDF] - retrieved 2016/06/02, original source: http://www.cellulose.org/userdocs/CIMA-TechnicalBulletin01.pdf
    
    Excerpt:
    
    Cellulose building thermal insulation is a recycled product made from recovered newsprint, the largest single component of the residential waste stream in most communities. Dry loose-fill cellulose insulation is installed in attics and walls with pneumatic blowing machines.
    
    Existing walls may be insulated by blowing insulation in through access holes. The holes may be at the top, bottom, and either inside or outside the building. A variery of methods are used to insulate new walls with dry cellulose.
    
    Techniques include using jigs or forms to fill open face cavities prior to installation of sheetrock. Various types of permanent retainers are also used in walls, crawl spaces, or cathedral ceilings. Cellulose insulation spray-applied in wet form is a self-supporting material.
    
    It relies on water, adhesive, or a combination of both to build bond strength to a substrate and within itself.
    
    Spray-on products may be used in wall cavities (fully open and dried before covering) or on other suitable exposed wall or overhead surfaces.
  • Cellulose Insulation Manufacturers Association, Technical Bulletin #2, "Standard Practice for Installing Cellulose Building Insulation, Op. Cit.
  • Cellulose Insulation Manufacturers Association, Technical Bulletin #3, "Standard Practice for the Installation of Sprayed Cellulosic Wall Cavity Insulation."
• European Cellulose Insulation Association, Website: www.ecia.eu.com/, Administrator Lucia Gross lucia.gross@ecia.eu.com.
  Excerpt: CIA unites the European cellulose manufacturing industry as a one voice.
  
  We are open for all genuinely respectable manufactures in European Union area. ECIA is willingly cooperating with associations, institutions, authorizes and stakeholders internationally. Our mission is to provide better energy and eco-efficiency by insulating the European buildings well with cellulose fiber insulation. The inaugural meeting was held in Brussels on 9/10/13.
• Lopez Hurtado, Pablo and Rouilly, Antoine and Vandenbossche Maréchal, Virginie and Raynaud, Christine A REVIEW ON THE PROPERTIES OF CELLULOSE FIBRE INSULATION. [PDF] (2016) Building and Environment, 96. 170-177. ISSN 0360-1323 - This is an author’s version published in: http://oatao.univ-toulouse.fr/25271
  
  Abstract excerpt:
  Cellulose fibre insulation is an eco friendly thermal insulation material made from recycled paper fibres. It offers good thermal properties and has a low embodied energy. However due to lack of expertise in its application and properties, cellulose insulation is not widely used in comparison to more traditional insulation materials.
  
  The present paper reviews the available research on cellulose fibre insulation, its manufacture, installation, and performance. The paper focuses the physical properties of cellulose insulation, the environmental factors that affect these properties, and possible means of future innovation.
• Menard's Insulmax cellulose insulation (dry applied - no water) specifications are at hw.menardc.com/main/items/media/GREEN083/Prod_Tech_Spec/InsulmaxCoverageChart11-22-2014.pdf
• Pal, R. K., Parveen Goyal, and Shankar Sehgal. EFFECT OF CELLULOSE FIBRE BASED INSULATION ON THERMAL PERFORMANCE OF BUILDINGS [PDF]  Materials Today: Proceedings 45 (2021): 5778-5781.
  Abstract
  Cellulose fibre based insulation can be employed to maintain comfortable indoor conditions inside buildings and to improve energy efficiency. The huge energy consumption for space cooling can be decreased by applying cellulose fibre as thermal insulation in the buildings because of its low thermal conductivity. Cellulose fibre insulation is made from recycled paper fibres and inorganic additives are used to prevent mould growth and increase fire resistance.
  
  Here an effort has been made to examine the suitability of cellulose fibre as an insulation for buildings under static, dynamic heat transfer conditions, embodied energy and environmental pollution aspects are also examined. Cellulose fibre insulation has lower value of embodied energy and environmental impact as compared to other insulation materials. Cellulose fibre has lower embodied energy than the conventional and unconventional insulation materials.
  
  Cellulose fibre can be utilized in the buildings for maintaining a steady humidity value in the indoor air. Cellulose fibre board has the mean thermal conductivity equivalent to materials like cork, polyurethane, recycled glass, recycled cotton and glass wool. The cellulose fibre board has incredibly low mean thermal diffusivity than other materials like cork, polyurethane, recycled glass, recycled cotton and glass wool.
  
  Consequently cellulose fibre has similar thermal performance under static heat transfer conditions to the best insulation materials and the thermal performance of cellulose fibre for insulating buildings under dynamic heat transfer conditions will be much better than other insulation materials. Cellulose fibre is also environment friendly, renewable, recyclable and has lower embodied energy.
• 15 U.S. Code § 2082 - Interim cellulose insulation safety standard, retrieved 2016/08/19, original source: https://www.law.cornell.edu/uscode/text/15/2082
• US Consumer Product Safety Commission. CELLULOSE INSULATION [Alert] [PDF] US Consumer Product Safety Commission, 1978.

• US DOE, TYPES of INSULATION [PDF] (2017) U.S. Department of Energy - illustrated above, a contractor is installing blown-in cellulose insulation into a building wall - CIMA

• U.S. Federal Regulation 16 CFR Part 1209 Consumer Products Safety Commission Interim Safety Standard for Cellulose Insulation
  and
  Consumer Products Safety Commission, Interim Safety Standard for Cellulose Insulation, 16 CFR Part 1209.
• U.S. Federal Regulation 16 CFR Part 460 FTC Trade Regulation Rule, Labeling and Advertising of Home Insulation
• Vėjelis, Sigitas, Ivanas Gnipas, and Vladislovas Keršulis. PERFORMANCE OF LOOSE-FILL CELLULOSE INSULATION [PDF] Mater. Sci 12, no. 4 (2006): 338-340.
  Abstract:
  Loose fill cellulose thermal insulation known as ecofiber, is a recycled product made from recovered newsprint and other paper feedstocks. The product consists of small tufts of paper, dry mixed with powdered chemical additives which improve the fire properties of the product and prevent mould growth.
  
  Loose fill cellulose insulation is used in new and renovating buildings. To warrant appropriate thermal-technical conditions and lifetime of this material it needs to take notice to the moist state of enclosures.
  
  When moisture content is known in building enclosures, loss factor of thermal conductivity due to materials dampen and select applicable thickness of thermal insulating material can be exactly estimated.
  
  The research results of moisture content of loose fill cellulose insulation in exploitation buildings are presented. Moisture content of cellulosic insulation is determined in one- and two floor buildings with masonry walls made of two layers of briks and with different thickness of insulating material layer.
  
  Also the influence of moisture content on the thermal conductivity is determined. Keywords: loss-fill cellulose insulation, moisture content, thermal conductivity.
• WSU, INSPECTING ATTIC INSULATION [PDF] (2006) Washington State University, Extension Energy Program, 2006, Web search 01/03/2011
  Excerpts:
  
  Types of blown-in insulation The two commonly used types of blown-in attic insulation are cellulose and fiberglass. Blown-in rock wool insulation is also available but its use in the Pacific Northwest is not common.
  
  Cellulose is a natural wood product and is made primarily from recycled newspaper. A fire retardant chemical is added to meet flame-spread and smoke-development requirements of today’s building codes. ...
  
  The R-value of loose fill cellulose is R-3.2 to 3.8 per inch2 Achieving the desired R-value depends on both the depth of the insulation and its density.

Cellulose Insulation Under the Microscope

This discusion has moved to its own page now found

at CELLULOSE INSULATION UNDER the MICROSCOPE - microscopic examination of cellulose insulation for identification & properties

...

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2023-05-08 by InspectApedia Editor - more research on recycled fiber building insulation:

@Fred,

More research - in case we turn out to have been right - on recycled fiber building insulation:

Intini, Francesca, and Silvana Kühtz. "Recycling in buildings: an LCA case study of a thermal insulation panel made of polyester fiber, recycled from post-consumer PET bottles." The international journal of life cycle assessment 16 (2011): 306-315.

This article is more focused on recycled PET bottles but also describes recycled polyester fiber.

An example of a contemporary insulating product made of recycled polyester fibers is at

ECOLAN/RECOLAN from K.E.F.I. - Kenaf Eco Fibers Italia S.p.A. - original source https://www.kenaf-fiber.com/en/ecolan.html

Adding to the confusion in identifying these products from a photo is that often materials are combined, such as a mix of recycled cotton and recycled polyester fibers.

See

Sakthivel, Santhanam, Selvaraj Senthil Kumar, Seblework Mekonnen, and Eshetu Solomon. "Thermal and sound insulation properties of recycled cotton/polyester chemical bonded nonwovens." Journal of Engineered Fibers and Fabrics 15 (2020): 1558925020968819.

Copy at RECYCLED COTTEN POLYESTER INSULATION [PDF]

Abstract
This research paper reports a study on thermal and sound insulation samples developed from recycled cotton/polyester
(recycled cotton/PET) for construction industry applications. The waste recycled cotton and polyester fiber is a potential
source of raw material that can be considered for thermal and sound insulation applications, but its quantities are limited.
While the quantities are limited, waste recycled cotton fiber was mixed with recycled/PET fiber in 50/50 proportions
in the form of two-layer nonwoven mats with a chemical bonding method. The samples such as cotton (color and
white), polyester (color and white), and cotton-polyester blend (color and white) were prepared. All the samples were
tested for thermal insulation, sound absorption, moisture absorption, and fiber properties as per the ASTM standard.
Also, behaviors of six recycled cotton/polyester nonwoven samples under high humidity conditions were evaluated.
The sound absorption coefficients were measured according to ASTM E 1050 by an impedance tube method, the
sound absorption coefficient over six frequencies 125, 250, 500, 1000, 2000, and 4000Hz were calculated. The result
revealed that nonwoven mats that are prepared from recycled/PET/cotton waste have confirmed more than 70% of the
sound absorption coefficient and the recycled nonwoven mats provided the best insulation, sound absorption, moisture
absorption, and fiber properties. The recycled waste cotton/ polyester nonwoven mats have adequate moisture
resistance at high humidity conditions without affecting the insulation and sound-absorbing properties.

Take a look at the photos in this paper as they look a bit like your sample.

On 2023-05-08 by InspectApedia Editor - some building insulation products have been made of polyester fibers

@Fred,

From just your photos I'm not certain what this insulation material is.

I can't make out shiny fiberglass nor fiberglass bonding resins in your image and the fibers look too short and irregular for that attribution.

I can't make out transparent/translucent fibers nor micro-spherules I associate with mineral wool or rock wool.

I'd speculate that this is a wood product or plant product insulation, BUT, the color, pale gray-white, and more, at the lower right in your photo I see an odd rectangular mesh that both hint that this could instead be a chopped/ground/shredded re-cycled material, even carpeting or fabric.

For decades some building insulation products have been made of polyester fibers.

See the lower right corner of my enlargement of your photo - below.

Please use the page bottom or top CONTACT LINK to contact us by email and I'll give an address to which you can mail a sample. Then when I'm back at our lab (end of June) I'll look at it under the microscope.

Initial supporting research:

Patnaik, Asis, Mlando Mvubu, Sudhakar Muniyasamy, Anton Botha, and Rajesh D. Anandjiwala. "Thermal and sound insulation materials from waste wool and recycled polyester fibers and their biodegradation studies." Energy and Buildings 92 (2015): 161-169.

Abstract:
This paper reports a study on thermal and sound insulation samples developed from waste wool and
recycled polyester fibers (RPET) for building industry applications. Waste wool fiber is a potential source
of raw material for thermal and sound insulation applications, but its quantities are limited. In order to
overcome the above problems, waste wool fibers were mixed with RPET fibers in 50/50 proportions in
the form of a two layer mat. Another set of three samples from 100% waste wool and 100% RPET fibers
were also prepared. All samples were tested for thermal insulation, acoustic, moisture absorption and fire
properties. Also, behavior of the samples under high humidity conditions was evaluated. An extensive
biodegradability study was conducted to analyze the conversion of organic carbon into carbon dioxide
by composting method for 50 days. Two layer 50% waste wool and 50% RPET mat provided the best
insulation, acoustic, moisture absorption and fire properties. The RPET/waste wool mats were absorbing
more than 70% incident noise in the frequency range of 50–5700 Hz. The RPET/waste wool mats have
adequate moisture resistance at high humidity conditions without affecting the insulation and acoustic
properties. 65–70% biodegradation was achieved for wool/RPET mats for 50 days composting period.

Copy here at

THERMAL & SOUND INSULATION from WASTE WOOL & RECYCLED POLYESTER FIBERS & THEIR BIODEGRADATION STUDIES [PDF] (2015)

On 2023-05-07 by Fred

Here is another picture of the same insulation in the Tuolumne County house not zoomed in as much. This house was built in 1975 in Tuolumne County, California.

Ok, I zoomed in with a triple stack magnifying glass and got this picture. Does this help identify it? Again, 1975 home in a rural Northern California town.

On 2023-05-07 by InspectApedia Editor - what is this chopped, blown fibrous insulation

@Fred,

Thanks for a "stump the chump (me)" photo. I can see why you'd ask, as that chopped, blown fibrous insulation doesn't exactly match our examples.

Most likely it's chopped fiberglass insulation or less-likely, blown mineral wool.

Take a look at (and post a sharp photo of) the insulation through the strongest magnifying glass you've got at hand and we might see the presence of resin binders used in fiberglass or of tiny spheres characteristic of mineral wool or slag wool.

On 2023-05-07 by Fred

I'm trying to figure out what kind of blown in insulation is in my attic space to make sure it is safe. The house was built in 1975 in Tuolumne County, California

On 2022-10-16 by InspectApedia (Editor) - concrete between floors in a single family residence is unusual

@Davis,

Please keep in mind that I have no information whatsoever about your building such as age, location, type of construction, etc. so I'm inspecting and trying to answer while peering at a photo, not totally sharp at that, as though through the eye of a needle.

What I can see LOOKS like concrete. It could be something else.

You wouldn't expect to find concrete between floors in a single family residence but might indeed in a high-rise building.

POKE or TOUCH it - to see if it's hard, and look for yourself for concrete that does indeed contain bits of stone.

On 2022-10-16 by Davis

@InspectApedia (Editor), awesome, thank you for your quick response! Is concrete common in between floors? This hole is on the ceiling, the pipe is coming from a bathroom in the second floor.

On 2022-10-16 by InspectApedia (Editor)

@Davis,

no, it looks like concrete

On 2022-10-16 by Davis

Hi, I have an open hole in my kitchen ceiling from some plumbing work. This is an old house built in 1920 but was renovated years ago. Does this look like asbestos insulation to you?

On 2022-09-25 by InspectApedia (Editor) - cellulose insulation is made of shredded newspaper

@Bob,

That's cellulose insulation -

Yep - you can make out those bits of news-print - common in insulation made of shredded newspaper

On 2022-09-25 by Bob

@InspectApedia (Editor),

That is a color photo. I think the upload makes it a littler more lofi. Here’s another image. I can see some paper with print in it. Asbestos wouldn’t be mixed in this correct ?

The thing that’s puzzling me is the jute insulation combined with it, but newer joists. It’s in between the ceiling and subfloor .

More photos

...

On 2022-09-25 by InspectApedia (Editor) - bits of newsprint indicate cellulose insulation

@Bob,

Is this a black and white photo? Scale ? I'm not sure what we're seeing; I *think* I see what may be bits of newsprint (circled on our copy of your photo) - if so then it's cellulose insulation.

If you can't find those key insulation indicators (like the images above on this page), I suggest comparing the insulation with those shown at

INSULATION IDENTIFICATION GUIDE - topic home

https://inspectapedia.com/insulation/Insulation-Identification-Guide.php

Let me know what you think.

On 2022-09-25 by Bob

Hello. I had a plaster ceiling falling down in our bedroom. Our house was built in the 1920’s. It’s odd because there are nominal joists above the room, with hemp/jute sheets stapled to them. Above that is some sort of blown in or loose insulation .

There was a brand new air conditioning/ heating system installed throughout the entire house in 2020 before we bought it. I’m trying to identify this insulation. Which came crashing down with the ceiling…

Question: identify this U.K. cellulose + fibre insulation - asbestos?

I'm concerned about this loft insulation - that it may be potentially dangerous (asbestos) and was looking for advice.

I've attached a couple of pictures to this email in the hope you could give me your opinion. I appreciate you can only tell so much from a picture which is understandable but also perfectly happy if you want to share this on the site if it helps other people out. Or I could try again?

Im from the UK and my house is old. Very old (1888). I have loft insulation that is also old and was disturbed a couple of years ago when we had work done in the attic.

The team at the time doing the work didn't seem worried about it. They did seem young and inexperienced however.

Anyway we had someone take a look in the loft a couple of days ago and told me that I had what looked like vermiculite potentially asbestos containing insulation. Which of course worries me greatly. Access to the loft is via a hatch in a cupboard in my young sons bedroom.

What you will see from the pictures is the disturbed insulation. It is loose fill and where it has broken up the colour is almost pale yellow. I can see what looks like pieces of old newspaper in it, not vermiculite hard pebbles although I haven't looked very close up.

Ive zoomed in on one of the pictures where you can clearly see print on old paper. I'm hoping this is cellulose but I suppose it could also be mixed with something else.

Ill be getting this tested to be sure but just wondered what you thought?

Moderator reply:

Your photos show cellulose insulation - chopped newsprint. Look closely and you can even read some of it.

But I also see some fibrous material whose identity is uncertain: that may be fine chopped newsprint that was very macerated, or it might be more fibrous, like mineral fibre if such was mixed into your insulation.

I'd like to see a sharp closeup of the insulation in your center photo of the three - that looks almost as if it's a mix of cellulose and mineral fibre.

I really can't say what is that loose powdery gray stuff in some of your photos. How much of that is there, and where did that material come from? A remnant from something else?

Reader follow-up:

The grey stuff is dust and small chunks of old cement maybe when the roof was redone. It is a very old building.

I have taken more pictures of the insulation it's self as I have taken some out for testing to be sure. I've taken a look at mineral wool and you are right, it does look similar but here in the pictures you will see the insulation more clearly. There is definitely paper visible, again With print on the page.

If you could take one last look at that it would be great.

Moderator reply:

That fibrous nature plus newsprint says we're back to thinking you have mineral fiber insulation with some cellulose insulation mixed in.
That's not a product I've seen.

This doesn't add up for me.

Possibly your cellulose insulation was shredded by an unfamiliar process;

your photos are not quite clear when I try to zoom in for an unambiguous look.

But cellulose (chopped newsprint - paper) insulation and also mineral wool insulation do not normally contain asbestos.

Check your insulation against the photos at

CELLULOSE LOOSE FILL INSULATION

and at

MINERAL WOOL - ROCK WOOL INSULATION

and also see

MINERAL WOOL / "Rock Wool" COMPOSITION

In my clip from one of your photos [above], we see what surely is newsprint but also some rather fibrous material. Any forensic or microscopic lab could take a closer look and identify the material.

Also please send me a sample... [address deleted] and when I'm back at our forensic lab I'll take a look.

About donating to InspectApedia.com, thanks but it'll be sufficient donation if you agree to my use of your photos and excerpts of our correspondence - default is to keep you anonymous unless you ask otherwise. If nevertheless you [or other readers] still want to make a financial contribution to InspectApedia.com, please instead identify your nearest shelter for battered women and send them a check.

On 2019-12-13 by (mod) - Does or did Pal-o-pac insulation contain asbestos?

Thank you for the question, Lawrence, Pal-O-Pac isn't an insulation with which I'm familiar.

[Click to enlarge any image]

The current Pal-o-Pak insulation trademark registration, as provided by https://trademarks.justia.com/ tells us that the insulation is a fire-retardant-treated cellulose (that's a paper product, not asbestos).

On 2019-12-13 by Lawrence McGourty

Does or did Pal-o-pac insulation contain asbestos?

On 2019-07-19 - by (mod) -

Gm

Thanks for the question.

I have not come across any references that claimed that there was asbestos used in or mixed with cellulose insulation cellulose is a paper or wood product. If there were asbestos it would be by cross-contamination from some other source.

On 2019-07-19 by G. Mickelson

Curious, has blown insulation ever contained asbestos? Home built in 1979. Is there a year from which asbestos was no longer used in building materials?

On 2017-05-27 by Steve

We had a home inspector for a prospective buyer identify mold in the attic.

I visually saw moderate mold growth on ceiling plywood. A mold mitigation company we called came out and said mold was in the cellulose insulation and that was its food source.

The attic had some exposure to water but nothing serious due to a water leak in the roof. It was replaced about 3 years ago, no problems since. I have read that this type of insulation is resistant to mold.

I now suspect they want to up sell their services to include replacement of insulation. Is this a common issue? how can I test to see if there really is mold in this blow in insulation?

On 2017-05-10 - by (mod) -

No, cellulose loose fill insulation is made of paper treated with a fire retardant

On 2017-05-10 by jeffrey webb

We want to know if cellulose loose fill contains asbestos?

On 2016-12-11 - by (mod) -

I think I don't understand your question. My cellulose insulation is not used to test indoor air quality.

If you are asking about testing indoor air for high levels of dust from building insulation, an acclaimed hygienist or other indoor environmental expert would probably collect air samples and dust samples and certainly if they were doing a proper job would first conduct a thorough visual inspection of a building for probable sources of problem dust.

On 2016-12-11 by Anonymous

How to test the air quality using cellulose insulation

On 2020-10-25 by (mod) - how to recognize cellulose building insulation

Probably all cellulose - when I click to enlarge your photos the resolution isn't very sharp so I can but guess.

Please see https://inspectapedia.com/insulation/Cellulose_Insulation.php for details

On 2020-10-25 by MJ

Thanks for the previous reply, Dan. Would I be presumptuous to assert that these are also chopped cellulose insulation? Same room just in a different area. Image 1and 2

...

On 2020-10-25 - by (mod) -

Your third photo is chopped cellulose insulation

On 2020-10-25 by MJ

Third photo of attic floor insulation

MJ said:

1930s home. Had a ceiling fan box replaced through the attic floor. Handyman raised concerns about the type of floor insulation. Can anyone identify this? Thanks.

Here's another angle

...

On 2017-09-18 by mod - fear of cellulose insulation - will cellulose building insulation burn?

Charles

Cellulose, a paper based insulating product, is treated with fire-retardant chemicals and, provided you buy a reputable, certified cellulose insulation product, ought to be fine to install.

Please see details at CELLULOSE INSULATION FIRE RESISTANCE

Watch out: however, some caution is justified according to the opinion of writers in at least some sources. Example:

When cellulose insulation burns in an attic space or within a wall, it typically burns from the bottom up, and it burns at such low temperatures that even the best thermal imaging camera (TIC) may not pick up the traces of heat. ... The tell-tale sign of a fire burning within cellulose is the smell of burning paper.
...

Cellulose is a very tricky material when it comes to firefighting. Its low combustibility is extremely beneficial to homeowners, but creates multiple challenges for firefighters.

Understanding how this material works and knowing what to look for when fighting fire in a structure that contains cellulose insulation will ensure your safety as well as the continued safety of the homeowner.
Firefighternation.com https://www.firefighternation.com/2011/11/28/fire-cellulose-insulation/#gref - Nov 28, 2011

On 2017-09-18 by Charles

I am looking to install a bathroom fan/light in the ceiling.

My ceiling is 2x4 construction with a layer of AVB and blown cellulose above it (which is in my attic). Is it ok to install? Is this a fire hazard? I was thinking of installing addition framing above the 2x4's for clearance and also looking for the smallest depth for a fan.

Cellulose just scares me with it being so flammable. Is it ok for it to be in contact with

This Q&A were posted originally at BATHROOM VENT DUCT TERMINATION

Question: using cellulose insulation below grade

(June 8, 2015) Greg said:
Is it ok to install blown in cellulose insulation below grade?

Reply: watch out for insulation that should not get wet

If you've got air and moisture barriers properly placed AND if you are confident that you do not have water leaks into the wall system you should be OK.

I would not install any open-celled water-absorbing insulation material below grade if it is in a location where it can get wet. You'd lose R-value, invite mold contamination, rot, or other problems, and generally you'll be unhappy when those problems occur.

A closed-cell foam, properly fire-protected, is a safer bet.

On 2013-03-21 - by (mod) -

Raza,

Cellulose insulation is treated with a fire retardant and does not support combustion. In addition there are U.S. & Canadian and U.K. standards for its treatment and testing for fire resistance.

In the links at the end of this article click on

Cellulose Insulation Fire Resistance - separate article on fire retardant test results on cellulose building insulation

to read details.

On 2013-03-21 by Raza.

Is the insulation panel made by fibrous (paper industry waste/sludge) material can be fire hazard? and also please let me know how can we check the fire resistant of that material?

On 2012-07-29 - by (mod) -

D

Cellulose building insulation is a wood product - usually made from ground newsprint treated with a fire retardant.

On 2012-07-21 by D

Does Green Fiber Cellulose insulation contain any aesbestos? or for that matter does any insulation today??

On 2012-06-28 - by (mod) -

Bob we welcome hearing reader opinions but it's important to recognize when they're just that - opinion. Or as Demming said, "in god we trust, everyone else ... bring data". There is no data that I've been able to find that supports your assertions.

Our own field and lab experience indicate that the fire retardants in cellulose seem to have the surprising side benefit of resisting mold growth and insect infestation.

And fiberglass is ... well ... glass, with resin binders. Glass has been found from the Egyptian tombs - it does not break down much on its own. But I'd agree that fiberglass insulation can become mechanically damaged - say by being walked-on - resulting in an increase in airborne dust and debris.

On 2012-06-27 by bob

cellulose insulation is one of the poorest insulator's on the market. It is dusty during and for ever after installation. It does settle because it moves with air currents. It will not seal holes or cracks and if it does get wet it soaks water and packs down; loosing what little insulation value it had.

Insulation is all about trapped air. Cellulose does not trap air, it will slow air down due to it being an obsticle until you dust the last of it off your floors and furniture.

This wet pack cellulose, the stuff that is sprayed on, takes for ever to dry and the adhesive breaks down with time and temp change, adding to the dust you breath. It may be that mold was not found on the cellulose but it will not inhibit mold growth in its cavity.

Don't be cheap and waste your money or your health. there are far better insulations than cellulose or fiber glass to be found.

and while i'm at it, rodents and bugs love cellulose and fiber glass to nest in. Fiber glass breaks down over time also and it dust into your living space and you breath that in.

...

Continue reading at CELLULOSE INSULATION FIRE RESISTANCE or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ASBESTOS FIREPROOFING SPRAY-On Coatings
• BALSAM WOOL vs CELLULOSE INSULATION
• BLOWN-IN INSULATION
• CELLULOSE LOOSE FILL INSULATION - home
• CELLULOSE INSULATION PROS & CONS
• CELLULOSE INSULATION FIRE RESISTANCE
• CELLULOSE INSULATION UNDER the MICROSCOPE
• INSULATION IDENTIFICATION GUIDE - topic home
• INSULATION LOCATION - WHERE TO PUT IT
• INSULATION R-VALUES & PROPERTIES for an extensive table describing the properties of different insulating materials used in buildings.
• WOOD FIBRE INSULATING PANELS

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CELLULOSE LOOSE FILL INSULATION at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING INSULATION

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