Homasote® fiber board company & product information:

Here we give a brief history of the Homasote® company and we describe its products. We also discuss hHow to recognize/identify Homasote® insulating fiberboard building sheathing products used as exterior wall sheathing and as interior wall & ceiling surfaces.

This article series describes and provides photographs that aid in identifying various insulating board sheathing materials used on building walls and roofs, such as Homasote, Celotex, Insulite, and Masonite, Upsonboard, Nu-Wood and other insulating board sheathing products.

Homasote®, Fiberboard & Insulating Sheathing Board Products

Homasote® Brand Boards & Panels: Composition & Identification

At FIBERBOARD SHEATHING IDENTIFICATION we explain that Low-density fiberboard panels and products trace their origin in the U.S. to Azel Storrs Lyman's 1858 patent for separating the fiber of wood and for the manufacture of paper and other purposes. (Jester 2014).

The Agasote Millboard Co. (Trenton N.J.) was formed in 1909, and as Jester notes, by 1916 that company was producing the widely-known Homasote brand fiberboard that probably has been a century-long thorn in the side of Celotex, Insulite Nu-Wood, and Masonite.

By 1910 in the U.S. the manufacturer of fiberboard made these products available to builders and homeowners for use as a sheathing product that was used on wall exteriors, wall and ceiling interiors, and even as roof sheathing.

In my personal experience and OPINION, and despite its description as quite weather resistant, general use of low-density fiberboard roof sheathing was a bad idea.

Image above: Homasote® 440 Sound Barrier panel fiberboard illustrated on sale at a Menards Lumber & Building Supply store.

[Click to enlarge any image]

Recycled Paper Comprises Homasote® Panels & Products

Definition of Homasote®:

Homasote® brand wallboard and panels used for building sheathing and historically for walls and ceilings as well as underlayments are a cellulose-based product made from re-cycled paper using water to form a slurry that under pressure is formed into panels to which small amounts of additives are given before the product is cut to desired size.

While we generally describe Homasote® as well as other fiberboard panels as a "cellulose" or "wood fiber" product, currently Homasote's products are actually produced principally from recycled or "post-consumer" paper and newspaper.

Interestingly, cardboard is separated from the paper waste stream and re-sold since according to the company the long fibers in cardboard are not compatible with Homsote® production.

Homasote's paper input is pulped and mixed with hot water to produce a gray slurry that provides the characteristic color of the final Homasote® board product line. The gray results from ink content of the recycled newsprint used in production.

Small amounts of a wax emulsion and a biocide are added to the paper slurry before that raw material is formed into forming molds that squeeze out water before the boards are dried and cut to final size.

The company informs us that Homasote® board is weather-resistant, structural, insulating, and has 2-3 x the strength of "typical light density wood fiberboards". - Retrieved & excerpted 2017/11/08, original source: http://www.homasote.com/about

Does Homasote contain asbestos?

No, no one would not expect this product to contain asbestos and the company affirms that in comments at their own website (8 Nov 2017 see citation links below).

But some other fiberboard brand products, even though made of cellulose, may contain asbestos due to cross-contamination.

That fiberboard asbestos concern is described

at SHEATHING, FIBERBOARD ASBESTOS CONTENT

Homasote® Identification: check color & texture & cross section

Despite widespread use of the word Homasote® to describe brown fibrous and soft board panels, actually Homasote is gray or in my OPINION gray-tan in color, as it's produced from post-consumer paper.

However once installed the product may have been painted or covered-over so an inspector cannot assume that she will always find the gray color without some digging into the structure.

The Homasote picture shown here is from a discontinued product previously sold at Lowes stores.

According to Homasote®,

[Homasote brand fiberboard products in] cross section would not show layers of fiber since our products, unlike other fiberboards, are not layered.

With aging our products normally have a yellowish brown tint otherwise they are gray.

In all cases, unsanded Homasote Products all have very visible patterns on the face and back side surfaces. As far as I can tell, none of the samples shown [at UNIDENTIFIED FIBERBOARD PRODUCTS] have our mold patterns.

Each fiber is coated with a wax emulsion thus making the panel weather resistant.

In a vertical application, should the panel get wet, the water will wick out the bottom as long as it’s installed properly and elevated off the bottom surface. In a horizontal application it will react like plywood and the water should not de allowed to pond on it especially after it stops raining.

Where structural shear strength is needed by using the company's recommended ring-shanked nails in a specified nailing pattern.

 

Homasote® Products & Homasote Company Information

As of November 2017 the following are excerpted from product information provided by the Homasote Company at the address given below.

• [1] Homasote® Company, 932 Lower Ferry Road, West Trenton, NJ 08628-0240 Tel: 800-257-9491 Ext 1332, or from outside the U.S. call 609-883-3300. Website: http://www.homasote.com/ , Email: Sales@homasote.com.
  
  Thanks to Homasote CEO Warren Flicker for technical review and comment on this article.
• Homasote® 440 SoundBarrier® floor, wall, ceiling sound insulation. Retrieved 2017/11/08, original source: http://www.homasote.com/products/440-soundbarrier
  Excerpt:
  
  440 SoundBarrier® is a special-density, structural board made from 100 percent environmental Homasote® cellulose fiber, a homogeneous composition manufactured with uniformly distributed protection against termites, rot and fungi and resistance to moisture. It also insulates, with twice the R-value of wood. Made with FSC® certified material.
• 4-Way® Floor Deck - a structural, noise-deadening subfloor and insulating, carpet underlayment made from multiple plies of Homasote® structural building board permanently bonded under extreme pressure with a water-resistant glue, trimmed to size and shaped with tongue-and-groove to form floor decking panels.
  
  4-Way is used as a structural sub-flooring in low-rise condominium and apartment developments, motels, nursing homes, professional buildings and private homes, especially where noise control is a prime consideration.
• Burlap panels - heavyweight jute fabric laminated to a nominal 1/2" structural Homasote® fiberboard, used in both residential and commercial construction as a finished paneling in its natural state or can be painted
• ComfortBase® - resilient board that cushions hard concrete, Molded, 98% recycled post-consumer paper, cellulose fiber structural panel available only in a 4’ x 4’ panel with kerfing on the underside.
• DesignWall Interior panels - sound deading wall panels, Guilford of Maine® FR 701 fabric laminated to ½" N.C.F.R.® structural Homasote
• Easy-Ply Roof Deck - structural, load-bearing decking in residential and non-residential buildings, Molded, recycled post-consumer paper, cellulose fiber structural panel made from 3 layers of 440 structural board with white vinyl flitter interior finish. Also available without vinyl flitter finish.
• Homasote EASYPLY® ROOF DECK PANELS [PDF] HOMASOTE COMPANY, 932 Lower Ferry Road, West Trenton, New Jersey 08628, Phone: (800) 257-9491 www.homasote.com, For Technical Support call Ext. 1332 or e-mail techhelp@homasote.com
• Firestall® Roof Deck - nailable Class "A" fire rated structural roof decking, made of multiple plies of Homasote structural board and a face ply of UL-listed N.C.F.R.®
  
  Homasote.® Firestall Roof Deck is composed of two materials. The interior facing ply is composed of one layer of Class A, N.C.F.R. Homasote and the exterior facing is composed of one or more plies; depending on overall thickness, of 440 Homasote structural board. It is supplied in a 2’ x 8’ panel size with the tongue and groove on the 8’ edge
• Homasote FIRESTALL ROOF DECK PANELS [PDF] Op. Cit. retrieved 2019/02/05 original source http://www.homasote.com/assets/files/installation/firestallroofdeck.pdf
• Homex® 300 - a Molded, recycled post-consumer paper with wax binder, cellulose fiber structural joint filler, does double duty as light duty forming material for walkways, patios pool aprons and driveways and as an expansion joint where masonry or concrete walls meet outside aprons, walks, patios or steps.
  
  Composition: Molded, recycled post-consumer paper, cellulose fiber structural panel made from 440 Homasote structural board.
• Ice Deck® O.T. - moisture-resistant structural panel that can be placed directly over indoor ice for temporary conversion of an ice rink for other activities.
• N.C.F.R. Homasote® - ... structural building board and substrate for interior or exterior application, offering constant insulation against air, moisture and noise penetration. It is a UL fire-rated structural building board and UL recognized component in floor protectors and wall shields.
  
  Fire Rated N.C.F.R. Homasote is made with 55% recycled, all wood fiber material completely impregnated with fire retardant chemical ingredients, treated for protection against termites, rot, fungus, and moisture absorption, and compressed into high-density, structural exterior building board. Made with FSC® certified material.
• Nova Cork panels - Natural sustainable cork veneer over 440 Homasote panel; a molded, recycled post-consumer paper, cellulose fiber structural panel.
• PINnacle™ Tackboards - finely sanded, soft-textured, formaldehyde-free tackboard for interior and protected exterior use. Composition: FSC® certified material, 00% recycled wood fiber, Formaldehyde and asbestos free

Homasote® Company History & Contact Information

The Homasote Company, originally named the Agasote Millboard Company, was founded in the U.S. (Trenton, New Jesey) in 1909 by Eugene H. Outerbridge as an "offshoot" of the Bermuda Trading Company.

The Homasote Company's original product was sanded millboard panels used to form the lining and sides of railroad carriages, later used for Vehisote, applied as automobile tops installed on Ford, Buick and other vehicles. In World War I Homasote® panels were used to construct field hospitals and military hospitals.

By 1909 Agasote Millboard's Trenton New Jersey factory began operation producing fiberboard.

In 1916 Agasote Millboard introduced their now world-famous Homasote sheathing board manufactured from recycled "re-pulped" newspaper.

In 1925 the company's board products were promoted as building and insulation materials. Older readers including the author [DF] will recall finding Homasote®or Thermasote® panels on walls and ceilings in homes and other buildings.

Starting in 1939, Homasote® was among companies providing modular constructed homes, making the company one of the early modular suppliers. The company's history page notes that their first modular home project in Valajo California put up 977 houses in 73 working days. Modern modular home construction is discussed at MODULAR HOME CONSTRUCTION.

That experience and product development was no doubt behind the use of Homasote's Precision Built System of Construction to put up 5000 miliatary homes in the Norfolk Naval Shipyard in Portsmouth VA (seen by this author).

The following is excerpted from the company's About-Us web page at http://www.homasote.com/about on 2017/11/08

... Homasote Company is the oldest manufacturer of building products made from recycled materials in the U.S., and the only manufacturer of its kind in the Americas. Our 600,000 square-foot factory complex [is in ] in New Jersey, ... Each production day we recycle (and keep out of landfills) up to 100 tons of recycled cellulose fiber.

• Contact Homasote Company, 932 Lower Ferry Road, West Trenton, NJ 08628-0240 USA, Website: http://www.homasote.com/ Email: sales@homasote.com

Asbestos Content in Gypsum-core Homasote exterior sheathing (gypsum board) product from 1940s.

Was there a Homasote product used in the early 1940s on the exterior of houses that looks like sheet rock? How long does this last for?

If it is still on the house, could it contain asbestos and/or contain mold due to lack of sunlight?

Was there "code" at some point that would have forced individuals who were to replace vinyl siding on the house over these boards to replace with proper products after a certain date? Thank you, K.B.C.

Reply: Properties of Homasote® type fiberboard compared with gypsum-based exterior wall & roof sheathing boards

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem with sheathing, leaks, and mold or asbestos sources in buildings - the concerns you expressed. That said, here are some things to consider:

Homasote® fiberboard sheathing is a wood fiber product, not a gypsum or plasterboard product. However there were indeed gypsum-based sheathing board products used on buildings both as wall sheathing (under siding and over studs) as well as roof sheathing.

Starting at the top of this article HOMASOTE HISTORY & PRODUCTS you will read that the ingredients of Homasote® panels are principally recycled newspaper with a small amount of a wax and a biocide.

Having inspected quite a few buildings that used this material, my OPINION is that it has proven surprisingly durable so long as it was kept dry.

Wet panel board or gypsum board material of any brand can become soft, and also one might find mold growth on the paper backing of the gypsum board.

To identify Homasote you can also see IDENTIFY Homasote® Brand Fiberboard

We also describe these two different product types in more detail:

SHEATHING, GYPSUM BOARD and

FIBERBOARD SHEATHING - Sheathing Celotex Homasote & Other (this article)

Also see FRAMING MATERIALS, AGE, TYPES where we describe the history of building framing and sheathing materials.

Some Gypsum board and plaster board products indeed contain asbestos as does some joint compound

Watch out: Indeed some gypsum--based drywall products did contain asbestos into the 1980's. I have not, however, tested nor seen test results specifically for exterior wall sheathing using that material.

I suggest sending a small sample, a square inch would be plenty, to a certified asbestos testing lab - the cost should be $10 - $50. U.S. Do let me know what you find as the results will be helpful to other readers.

Even when gypsum board or plaster board did not itself contain asbestos, some joint compounds did contain that material right up into the 1980's.

But used as an exterior sheathing, at the buildings I've seen, there was no top coating of joint compound and tape on this type of sheathing board (as there would be on drywall used for interior wall coverings).

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Recent questions & answers about how to identify the brand or manufacturer of fiberboard sheathing products used inside or outside of buildings

Question: How do you repair the peeling of outside layer of homesote?

2020/04/14 Alex said:

How do you repair the peeling of outside layer of homesote? Mine is white and was used under my decks.

The outer layer is peeling on some, how do I cost efficiently repair them?

Reply: repair damage to Homasote fiberboard insulating sheathing where it is exposed outdoors

Alex,

Thank you for a helpful question:

How do we repair damage to Homasote fiberboard insulating sheathing where it is exposed outdoors?

I have read other reports on DIY repair of exposed Homasote fiberboard as well as having done some repair and removal and replacement myself.

My OPINION is that while you can blob on an exterior sealant and trowel it flat, nothing will make a lasting repair on a soft fiberboard insulating board that was not intended to be left exposed to the weather and that is soft and so - exposed.

About the best we can do is to dry, stabilize, seal the material and protect it from the weather

1. Dry out the damaged Homasote: wait until the damaged homasote board is completely dry before proceeding.
2. Paint the surface of the Homasote board with an alkyd primer/sealer in the area of damage and immediate surrounding area or all Homasote surfaces that are exposed to weather - this will stabilize the material and reduce further loss of Homasote board fibers
3. Fill small holes or penetrations with an exterior-rated sealant or caulk.
   
   While the bond between such sealants and fiberboard is generally poor - due to either a wax or asphalt coating on the board or in areas of damage, due to having to bond to soft, loose fibers - having painted the damaged surface will give a better bonding surface
   
   Watch out: I do not recommend using Dash Patch™ nor joint compound to repair Homasote where it's exposed outdoors. Indoors those products can work, as you'll read in a our repair article I'll cite below.
4. Large holes or severely-damaged Homasote board should be cut out and replaced, outdoors use a weather-resitant material
5. Protect the Homasote board from weather exposure

See complete details at

FIBERBOARD PANEL REPAIR

 

On 2016-08-28 by (mod) - asbestos used in wall papers & coverings

Watch out, Savannah. In addition to possible asbestos in some old wall coverings, some old wallpapers, particularly ones with green in the pattern, contained arsenic.

At ASBESTOS LIST of PRODUCTS we include what's probably the most-extensive list you'll find for asbestos-containing products found in or around homes.

There I haven't listed "asbestos containing wallpaper" but such products might have existed, particularly where an insulating or strengthening fiber was wanted or where fire resistance was a concern.
Keep in mind that asbestos may be present in some plaster and gypsum products found beneath wallpaper too.

Research citing asbestos use in films and papers used on walls:

• Breiner, R. "Asbestos-plastic film laminates." U.S. Patent 3,770,569, issued November 6, 1973.
• Gerek, Gene, and Rowland S. Hartzell. "Asbestos-foam laminates." U.S. Patent 3,522,140, issued July 28, 1970.
• Newman, Arnold H. "Insulated wallpaper." U.S. Patent 4,039,709, issued August 2, 1977.
• Prain, Willis A., "Wallpaper steamers." U.S. Patent 3,158,139, issued November 24, 1964. (asbestos used in this device not directly in wallpaper)
• [5] "Roof Shingle Tear-Off Procedure for Homasote Products", PDF document, Homasote Co., 932 Lower Ferry Road, West Trenton, New Jersey 08628-024, U.S.A. 800-257-9491 website: at www.homasote.com
• SJJ, Langford AL, and Textiles Pearson. "Wallpaper (1827) n. Paper, or paperlike material, usually decorated in colors, which is pasted or otherwise affixed to walls or ceilings of rooms. Wall stress (1) In a filament‐wound pressure." - used atop asbestos cement wallboard
• Werhane, Patricia H., Jenny Mead, Regina Swart, and Mollie Painter-Moreland. "South African Mining and Asbestos-Related Diseases (a)."
  Asbestos mining tailings were mixed with cow dung or mud used to paper or line walls in houses.
• Lewis, Herman. "Cement composition." U.S. Patent 1,595,897, issued August 10, 1926.
  Used asbestos in wall lining products

On 2016-08-28 by Savannah

I live in a 1920s home and noticed the wallpaper detaching from the plaster wall. I started pulling it off put realized it may contain asbestos. Anyone have experience, should I be concerned?

On 2016-01-24 by (mod)

Woody, Fiberboard sheathing is a wood fiber product. You're welcome to use our page bottom CONTACT link to send me photos of your sheathing and of any markings on it.

On 2016-01-24 by Woody

hey.. bought a 1940 house and have found various areas where asbestos has been located and re mediated but thought we had it all out.. found a Celotex board that only has Celeotex Lath.. this is a fiber board and need to find out if this was an asbestos product.. have a pick if that helps

thanks, Woody

Question:

I know per your articles that Celotex interior fiberboard usually does not contain asbestos but the directions on the back of mine talk about spraying it the day before installing it. My question is what might that spray do to the product?

I'm enclosing a picture of my product label. I find no other product marking however and want to be assured that it is not something containing asbestos.
Any thoughts would be appreciated. - Anon. by private email 2015/12/14

Reply:

Thanks for the question and also for the image - it was one I've not seen and it contains helpful details.

In the article above in the Celotex section I've posted your image of the Celotex instruction label discussing wetting the wallboard before use in plastering

OPINION: The spray was intended to boost the adhesion of plaster when this board was used as a substitute for (earlier) wood lath. These products were somewhat water resistant, some including waxes specifically for that purpose.

Wetting wallboard 24 hours before installing it as a plaster base would have increased its moisture content a bit; I doubt it'd have become too soft to apply or the manufacturer wouldn't have advised spraying both sides.

In this context I wouldn't expect other problems (such as mold growth) from this step as the board was to be installed to studs or ceiling joists promptly.

...

Continue reading at a href="../structure/Fiberboard-Sheathing-Identification-Key.php">FIBERBOARD SHEATHING IDENTIFICATION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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• SHEATHING, EXTERIOR PRODUCT INDEX

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HOMASOTE HISTORY & PRODUCTS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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