Fiberboard insulating sheathing used on or in building ceilings & walls:

This article describes and provides photographs that aid in identifying fiberboard or cellulose board or wood-product insulating board sheathing materials used on building walls and ceilings, such as Homasote, Celotex, Insulite, and Masonite products.

We also answer the question about whether or not these products are likely to contain asbestos.

Fiberboard Ceiling & Wall Sheathing on Building Interiors

Fiberboard wall and ceiling panels were widely used as an interior wall covering in both raw form (brown material in our photo) in attics and basements and more-often in a finished form in the living area where a coating or painted surface gave a more-finished appearance.

Finished surface fiberboard panels are shown at the top of this page and in other examples in the article that follows.

[Click to enlarge any image]

Often we find, or used to find, fiberboard wall and ceilings in homes built in the 1920's to 1940's and without other building insulation (in the original construction).

With a few rare exceptions, fiberboard panels used on building interior walls and ceilings are a soft, 1/2" thick or thicker board made of wood - it's a cellulose product.

Fiberboard sheathing or interior fiberboard ceiling and wall panels do not contain asbestos except in the case of cross-contamination where both asbestos-containing and non-asbestos products may have been manufactured at the same site.

Fiberboard ceiling tiles were also widely used in the 1940's and 1950's, using an embossed wood or other pattern, such as the Nu-Wood product line illustrated

at SHEATHING, FIBERBOARD ASBESTOS CONTENT

The ceiling panels shown just below were used as both an insulating panel and a finished-surface below a flat roof in a home constructed in 1960 in Two Harbors, Minnesota.

Reader question: does this brown fibrous ceiling material contain asbestos? (Netherlands)

...

We just bought a wooden house which is built in 1948 and we came across to a material in the living room ceiling.

We are located in the Netherlands. We don't know what it is. Previous owners had a hole where they had a ceiling light hanging. We found the material in this hole. Seems like it is big tiles. Please see the pictures. - Anonymous by private email, 2/11/2017

Reply: probably not

'm not 100% certain from your photos seen so far, but to me that material looks like a wood product that we call hardboard or "masonite" - search InspectApedia.com

for MASONITE HARDBOARD if the material you are seeing is hard, or if it's soft - that is if you can push a pencil into it, it's probably a wood product or cellulose product fiberboard.

Typically hardboard used on interiors is 1/4" thick or thinner while softer fiberboard sheathing used on ceilings and walls may be 1/2" or thicker and often is covered with a finish coating and perhaps decorative groovings in more-sophisticated products.

Reader follow-up

Just to clarify where this material is hanging please see the pdf attached. I did a simple illustration to explain better. So the white ceiling you see on the picture is actually just plywood

The material I am suspicious of is just above that plywood or indeed just masonite.

There is a gap in between. 3rd and 4th images are just the tile of that suspicious material which came off. I am not sure if this is clear. I also touched this yellowish material and it is a little soft. What do you think?

Reply:

If the material is soft it's most-likely a wood product or cellulose insulating board - very similar to Masonite hardboard but thicker, softer, lighter. It was widely used as an insulating sheathing board on walls and ceilings.

We illustrate this product also

at SHEATHING, FIBERBOARD

Note that I can't quite make out your photo: very yellow, fibrous material in panels may also be fiberglass insulating panels or ceiling tiles, though your other ceiling-interior photo above shows more-characteristic brown, patterned wood or cellulose board product.

Keep in mind that even if a ceiling panel contained asbestos, if the panel is covered, un-damaged, not releasing debris into the occupied space it's not much of a concern and the recommended course of action is to leave it alone.

Reader follow-up: tests found this cellulose or wood product as not asbestos.

I thought I'd give you an update on this. Last week we had a specialist checking the whole house for possible asbestos and indeed he said this is not asbestos. It is just a wood product for insulation.

Also see SHEATHING, FIBERBOARD ASBESTOS CONTENT

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2023-03-19 by InspectApedia Editor - fiberboard panels used as insulation and roof base

@Elise,

Sure, at least I'm willing to GUESS:

From the 1960's it was popular to use a thick wood- or plant-fiber based panel, often 3" thick or more, that doubled as both an insulating panel and a surface to which a roof could be applied.

(This reader's questions and photos were originally posted at

ROOF INSTALL, INSPECT, & REPAIR)

On 2023-03-19 by Elise

Can someone tell me what kind of sheathing system this is? Appears to be panels with a fiber-like material. Building was constructed around 1970 or so but unknown if this is original to the building.

...

On 2021-11-09 by (mod) - what is the right way to identify or classify fiberboard products?

John Marker,

I apologize for the bad link in my earlier response.

Your post under the name John Marker is, curiously, identical in the link it offers, to a post found at our

article UNIDENTIFIED FIBERBOARD PRODUCTS posted under the name Bob Rutledge. Unfortunately duplicate posts by various pseudonyms do not reflect well on their author.

Nevertheless we provide a researched answer to your comment:

Here we seem to have tripped over a bit of confusion about identifying fiberboard sheathing products.

1. What is the Type of fiberboard ?

There is the 1st question of type of fiber board such as HDF, MDF, and LDF three different densities or hardness has of otherwise a similar material. Your question suggests these as the right way to identify hardboard.

See DEFINITIONS, ENGINEERED WOOD HDF LDF LVL MDF MDO OSB where we describe the differences between HDF, LDF, MDF, etc.

Also see SIDING HARDBOARD IDENTIFICATION & CLAIMS where we describe different hardboard brands, product failures, warranties

But by "identify hardboard" (or MDF or LDF) many readers are asking something else. They want to identify the brand or product or they want to know the constituents of the product and they want to know if it contains asbestos.

2. What is the Brand or manufacturer of fiberboard ?

Separate from the fiberboard type question is that of identifying the specific brand of fiber board.

At FIBERBOARD SHEATHING IDENTIFICATION you will find a complete list of fiberboard manufacturers, past and present, along with visual clues that can help identify specific brands.

3. What is the Asbestos content in fiberboard ?

Separate from the questions above is whether or not any fiberboard sheathing or siding, basically a plant product, contains asbestos: to which the answer is generally no with rare exceptions principally from cross-contamination.

At SHEATHING, FIBERBOARD ASBESTOS CONTENT you will find an answer to that question along with explanation and citation of expert sources.

Also see HARDBOARD Masonite™-like INGREDIENTS

The articles in this series address all of those questions.

Using our reply to your identical post under the name Bob Ruteledge

at UNIDENTIFIED FIBERBOARD PRODUCTS we continue:

@Bob Ruteledge,

Thank you for the question on asbestos in fiberboard and for the reference you cited.

Your reference to Kollmann's article does not address your asbestos question.

In the Recommended Articles above you will see a thorough exposition of the various types of fiberboard, such as HDF, MDF, LDF, and the properties of each;

In the article on this page, by "identification of fiberboard" we refer not to the type but rather to its brand or manufacturer, though fiberboard type can be one of the data points in that determination.

Your Kollman citation is described by the following article in Principles of Wood Science & Technology:

• Kollmann, Franz FP, Edward W. Kuenzi, and Alfred J. Stamm. FIBERBOARD [PDF] In Principles of Wood Science and Technology, pp. 551-672. Springer, Berlin, Heidelberg, 1975. - retrieved 2022/03/18 original source: https://link.springer.com/chapter/10.1007/978-3-642-87931-9_6
  
  Abstract
  There are various types of fiberboard1, and unfortunately the terminology is not yet internationally standardized. Neverthelesss, one fundamental definition generally is recognized (FAO, 1958/1959, p. 4):
  
  “Fiberboard is a board generic term encompassing sheet materials of widely varying densities manufactured from refined or partially refined wood fibres or other vegetable fibres. Bonding agents and other materials may be incorporated in the manufacture of the board to increase strength, resistance to moisture, fire or decay or to improve some other property.” In the technical sense the ISO-definition is more precise:
  
  “Sheet material generally exceeding 1.5 mm in thickness, manufactured from ligno-cellulosic fibers with the primary bond from the felting of the fibers and their inherent adhesive properties. Bonding materials and/or additives may be added”.
  
  Excerpt:
  
  The origin of wood fiberboard goes back to Japan where as early as in the 6th century B. C. heavy papers were used for the construction of walls for small houses. In Europe a patent was granted to the British inventor Clay in 1772 for the application of "papier mache" (Neu88er, 1957) not only for use in dwellings, furniture, doors, but also for carriages.
  
  The idea of using the new material for big stiff building elements was evident. Since the middle of the 19th century, the proposals for use of fiberboards have greatly increased. More than 200 patents were issued in this field between 1858 and 1928 (Rossmann, 1928), more than 600 patents until1957 (Neusser, 1957).
  
  In spite of these early developments the actual fiberboard industry started near the beginning of the 20th century in England and in the U.S.A. The development up to 1926 was rather sporadic and without a remarkable increase in capacity.

Note in that author's own abstract the phrase "ligno-cellulosic fibers " - that means plant-based fibers.

"Lignocellulosic fiber is a scientific name that refers to natural fiber, because all plant fibers are constructed by few constituents (cellulose, hemicelluloses, and lignin). Most of plant fibers contain 50%–70% of cellulose ..." - sciencedirect.com 2021/11/07

Also see

• Kollmann, Franz FP, Edward W. Kuenzi, and Alfred J. Stamm. Principles of wood science and technology: II wood based materials. Springer Science & Business Media, 2012.

Asbestos is a mineral, not a plant.

Asbestos is indeed un-common in any fiberboard products but there are exceptions, such as by rare but known cross-contamination, as we describe at

SHEATHING, FIBERBOARD ASBESTOS CONTENT

You will want to read that article.

On 2021-11-08 by john marker [pseudonym] - the best factor for classifying fiberboard is the density

AUTHOR: john marker (no email)

COMMENT: Perhaps, the best factor for classifying fiberboard is the density. This is internationally recognized. There is a rather simple difference between pressed and
not pressed sheets hut the range of qualities is wide and there is an overlapping.

Another point which should be taken into consideration is the fact that wood fibers are blended occasionally with mineral fibers (such as asbestos), plastics and with other chemical additives. Some half-hard fiberboard contain no less than 20% of thermoplastic bonding agents.

[Poster's promotional link to an article by Kollman et als is deleted but cited in our reply above - Ed. ]

So does this mean that an old fiberboard ceiling or wall from 50s or 60s could have asbestos added in it?

On 2021-11-02 by Inspectapedia Com Moderator (mod)

@Susie smith,

Got it.

Indeed some white or gray-colored MDF or other board products contained asbestos. You'll want to treat yours as "PACM" - presumed asbestos containing material - until you've tested a sample.

On 2021-11-02 by Susie smith

@inspectapedia.com.moderator, These board products are visibly different in colour (whitish gray throughout) than cellulose-based or plant-fibre-based fiberboard products (tan or brown in colour
This is what I'm talking about as you are referring me to this link about this type of fiberboard as mine was brownish color.i saw no white other than the paint and it was in a mobile home for ceilings

On 2021-11-02 by inspectapedia.com.moderator (mod)

@Susie smith,

No, those are not our words.

I recommend that you look at the suggested articles above.

On 2021-11-02 by Susie smith

@inspectapedia.com.moderator, so I'm other words if its not white or looks like the cement kind it should not have asbestos as the board in the link looks more like drywall

On 2021-11-02 by inspectapedia.com.moderator (mod)

@Susie smith,

Usually not but possibly; see

LOW DENSITY FIBERBOARD ASBESTOS PRODUCTS - Watch out: occasionally LDF contains high levels of asbestos

On 2021-11-02 by Susie smith

Asbestos, plaster of Paris, clay, turpentine, paraffin wax, or other materials were added to some mixes to improve fire resistance and produce other desirable qualities such as stiffness, hardness, smooth surfaces, increased strength, or durability

So does this mean that old 50s and 60s ceiling made out of the fiberboard type stuff could have asbestos added?

On 2021-09-28 by inspectapedia.com.moderator (mod)

@Julie,

The use of asbestos in building and other products was never restricted by product dimensions, weight, or other such parameters.

On 2021-09-28 by Julie

When you say ceiling tiles,are you meaning any size ceiling board,panel,sheet or just the smaller square type?

On 2021-08-25 by inspectapedia.com.moderator (mod)

@Julie,

Some paints contained asbestos, as reinforcing fibers or fillers, particularly paints intended for heat or fire resistance or some used as waterproofing coatings such as foundation paints.

The practical hazard from ALL of these materials comes when they are disturbed.

See CEILING PAINT TEXTURED ASBESTOS

Also, Julie you could really help me out here - by trying some of your questions in the on-page search box that searches this website.

That will let me know - through you - if we are actually missing information you need, or if we need to make it easier to find or to read, and it'll let me otherwise concentrate on research.

Largely provoked by your discussion I spent a good part of today adding some new material you might like at

LOW DENSITY FIBERBOARD ASBESTOS PRODUCTS - Watch out: some LDF contains high levels of asbestos

https://inspectapedia.com/structure/Fiberboard-Sheathing-Asbestos.php#LDFAsbestos

When you read this be sure you notice how easily you can distinguish this asbestos product from other plant-based low density fiberboards.

On 2021-08-25 by julie (no email)

Re-posting lost comment

AUTHOR: julie (no email)

COMMENT: @inspectapedia.com.moderator, ok that is more easily understood and what about paints down the years as if people repainted the fiberboard ceiling,could the paints contain asbestos?

On 2021-08-25 by inspectapedia.com.moderator (mod) - is there a meaningful risk of asbestos in fiberboard ceilings ?

@julie,

Yes you make a fair point, taken from our own data; however before getting too worried about your fiberboard ceiling - if that's what we even have in this case - you'd need to identify your ceiling as Celotex; It's not highly likely: mostly you'll find that product used as exterior building sheathing, and it looks quite different, often black or very dark, and not easily painted.

Start by making sure we know what your ceiling is.

See

FIBERBOARD SHEATHING IDENTIFICATION

then see

CELOTEX HISTORY & PRODUCTS

On 2021-08-24 by julie - possible asbestos in some Celotex products

@inspectapedia.com.moderator,

Asbestos was used in some Celotex products and/or may appear in some Celotex products such as cellulose-based insulating board depending on when and where the product was manufactured.

On that basis, if the age of a Celotex™ ceiling is in that range it would be prudent to treat it as PACM.[9] Confirmation of asbestos content use & dates pending - Ed.]
so i wonder about this,if mine was this brand fiber board

On 2021-08-24 by inspectapedia.com.moderator (mod)

@julie,

For most circumstances there's not an asbestos worry: fiberboard is a cellulose or plant-based product. It is not an asbestos product. There was some concern for cross-contamination by asbestos for some product runs at certain manufacturers;

See details at FIBERBOARD SHEATHING INGREDIENTS

a quick search of InspectApedia.com using the on-page search box for "asbestos in fiberboard"
finds

SHEATHING, FIBERBOARD ASBESTOS CONTENT

In that article, in discussing the claim by some unidentified folks that some Celotex fiberboard contained asbestos, we report:

There was some question, not substantiated by any research I could find, that because some wood fiber board products may have been made at the same site where asbestos-containing materials had been used, that there may have been some cross contamination; that theory has not been supported by research articles that I've found nor by lab tests yet provided to us.

We continue to research that question and if you have found ANY authoritative source with actual information, please let me know and give me the reference for our review.

Then you should also read.

Watch out: And your final reading assignment for today - until another - most-welcome - question is

OTHER PEOPLE's MONEY

Where you'll read our opinion that if you press someone for an absolute guarantee in a world where that's not reasonable, it's going to cost you money - money that you would probably not spend if you were familiar with the topic.

On 2021-08-24 by julie - so can you guarantee there is zero chance of asbestos being mixed into my ceiling material?

@inspectapedia.com.moderator,
so if a ceiling was made of a fiberboard or wood product in the 50s then there would be no chance of asbestos being mixed in it as some things ill read says it was mixed in some fiberboard

On 2021-08-24 by inspectapedia.com.moderator (mod)

@julie,

No I don't think I said that and I surely don't think that.

On 2021-08-24 by julie

@inspectapedia.com.moderator,
so basically what your saying is its never been found in whole sheet or large panels of a ceiling other than drywall material or the square tiles. i dont believe they even put drywall in mobile homes in the 50s.

mine appeared to be something other than drywall or small tiles and mine wasnt long skinny panels either,more like a large panel of some sort.im thinking more toward the fiberboard but i have read where asbestos was sometimes added to fiber boards.

thats where im getting confused

On 2021-08-23 by inspectapedia.com.moderator (mod)

@julie,

I really would like to be more helpful but from just your text I have no idea what we are looking at. If your ceilings are made from a wood product fiberboard they would not contain asbestos. If your ceilings are plastic they would not contain asbestos.

At this point we don't know what's on your ceilings; and if it's fiberboard we don't know which product.

If your ceilings are made from drywall or some ceiling tiles any of which were manufactured in the US before 1986 then it's possible that they contain asbestos.

On 2021-08-23 by julie

no it appeared to be some wood or board material,we had a leak and removed it and it didnt appear to be white like drywall or sheetrock material. So im wondering if it was known for asbestos to be in large ceiling panels or boards of whatever mobile home manufacturers installed those days

On 2021-08-22 0 by samie - asbestos in a 1950s mobile home ceiling ?

would asbestos be in a 1950s mobile home ceiling.the ceiling is not tiles,it is a panel or board material maybe fiber board

On 2021-05-29 by (mod)

@julie,

Possibly if someone put drywall or gypsum board on the ceiling.

On 2021-05-29 by julie

would asbestos be in a 1950s mobile home ceiling,not small tiles but appears to be some board material?

On 2020-05-03 - by (mod) -

I don't recommend trying to soften ceiling tiles in order to make it easier to nail them.

The problem is that the tile will simply disintegrate and fall apart. However you do need to use a nail that is sufficiently fine or small in diameter and yet long enough to shoot through the tile. Usually people use a stapler.

On 2020-05-03 by Ganiyu Akintayo

I need help on how to soften ceiling board. I bought Kalsi Nigerite 4ft x 4ft size some large PC's about 3 years but some leftovers to be used now. But when nail is used to tack the edges,it breaking? It's too hard. What can I do? I need to use them for some ceiling cover in my extra rooms

On 2019-10-28 - by (mod) - asbestos in foam fiber ceiling panels?

Unfortunately I don't think we can tell a brand or product name from a smooth White fiberboard ceiling panel. What is the concern in the roofers case?

If it's asbestos you can address the question either by having a sample tested or by noting the edge of the house or ceiling, or by making sure that the materials going to be undisturbed in the first place. If it's something else we'll have to hear the specifics.

The ceiling panel photo that you copied from our website is a very thick fiberboard panel that was used to form both a flat roof deck as well as the interior finished surface in a 1960s home constructed in northern Minnesota.

On 2019-10-28 by Tyler

Hello, I have a foam/ fiber type ceiling that is in the attached photo. Do you have an idea to the brand or style. I am getting the roof replaced and the roofer is nervous.

Thank you

Tyler

On 2019-04-12 - by (mod) -

Sorry, no Roger. It would be helpful to know the age of the material or at least the building; that way we can probably find the most-likely candidate producing firms. I think we're looking at a pre-fab insulated ceiling panel / roof decking in a flat or low slope building. Right?

We have a companion article to this page - at FIBERBOARD SHEATHING IDENTIFICATION

If I can find the panel in your photo I'll add that information here and there .

Perhaps other readers will recognize the panels.

On 2019-04-11 by Roger Hankey

Do you recall the name of this soffit panel or manufacturer
IMAGE LOST by older version of Clark Van Oyen’s Comments Box code - now fixed. Please re-post the image if you can. Sorry. Mod.

On 2018-06-26 - by (mod) -

Steven

I'm sorry but we have to reply with some questions.

What panel. What size. What wait. And what's the condition of the fiberboard surface?. Certainly itv's in general, a soft material and I would not trust it to hold something heavy there just adhesive alone .

On 2018-06-26 by Steven

How well adhesive hold a panel to the fiber board

On 2017-08-29 by Anonymous

Will sheetmetal roofing screws hold the roof on, if it they are sunk into the material about 1 1/4 inch depth. Roofer tells me I need to add plywood to the entire roof first, and I say that the roofing deck material already on there is made so it does not require any additional weight/plywood sheets. Thanks.

On 2017-08-29 by stevo

Hi. I have a ceiling exactly like your 3rd pic from the top........2 x 8ft x 2" sheets placed over the beams in my 1950 renovation project house. Some leaking has occurred and I want to replace some of the panels. Do you know what that material is? Who is mfg?

I talked with Homasote and they said they have EasyPly roof deck to substitute.

But, since I am not sure, I am wondering if you know if EasyPly will work, and if so, that I can have a standing seam metal roof to be attached directly to this roofing material like the one in your picture above.

...

Continue reading at LOW DENSITY FIBERBOARD ASBESTOS PRODUCTS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• HARDBOARD Masonite™-like INGREDIENTS
• SHEATHING, FIBERBOARD
  • CANEBOARD PANELS
  • CARDBOARD CORRUGATED FIBERBOARD
  • CELOTEX HISTORY & PRODUCTS
  • DEFINITION of FIBERBOARD SHEATHING
  • HISTORY of FIBERBOARD INSULATING SHEATHING
  • HOMASOTE HISTORY & PRODUCTS
  • SYNONYMS for FIBERBOARD SHEATHING
  • FIBERBOARD CEILING & WALL COVERINGS
  • FIBERBOARD MANUFACTURERS & BRAND NAMES
  • FIBERBOARD PANEL REPAIR
  • FIBERBOARD PLASTER BASE SYSTEMS
  • FIBERBOARD ROOF SHEATHING
  • FIBERBOARD SHEATHED WALL BRACING
  • FIBERBOARD SHEATHING ASBESTOS CONTENT
  • FIBERBOARD SHEATHING INGREDIENTS
  • FIBERBOARD SHEATHING FIRE RATINGS
  • FIBERBOARD SHEATHING IDENTIFICATION
  • FIBERBOARD SHEATHING INSECT DAMAGE
  • FIBERBOARD SHEATHING MOLD CONTAMINATION
  • FIBERBOARD SHEATHING MSDS
  • FIBERBOARD ROOFING & FIBER-WOOD ROOFING
  • FIBERBOARD PROTECT from WATER
  • FIBERBOARD SOUND INSULATION
  • LOW DENSITY FIBERBOARD ASBESTOS PRODUCTS - Watch out: some LDF contains high levels of asbestos
  • SHEATHING FIBERBOARD CONSTRUCTION
  • SIDING HARDBOARD IDENTIFICATION & CLAIMS
  • SUNDEALA BOARD COMPOSITION & HISTORY
• SHEATHING, EXTERIOR PRODUCT INDEX

Suggested citation for this web page

FIBERBOARD CEILING & WALL COVERINGS 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 INTERIORS

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