Fiberboard insulating sheathing identification guide:

In this article series we provide fiberboard product names and we describe the components, properties, and applications of various fiberboard, hardboard, and insulating board or sound deadening board products. We also answer questions such as do Celotex or Homasote or other fiberboard and insulating board products contain asbestos? fiberboard water resistance, fiberboard recycling.

Fiberboard Sheathing Identification FAQs

These questions and answers about identifying fiberboard sheathing were posted originally

at FIBERBOARD SHEATHING IDENTIFICATION - home - so be sure to review that article too.

On 2023-06-25 by Jeff Leonas - ok to install new windows atop black fiberboard ?

I am replacing three 4`x 8` horizontal double slider windows. When I removed the exterior window trim I saw that the old nailing flange window was installed over what I call black fiber board. It is that stuff you can break apart very easily.

I remember back in the day they would put plywood on the corners and this stuff in between. Can I install my new nail fin windows over this stuff and still have a tight sealing window?

Reply by InspectApedia Publisher - Can I install my new nail fin windows over this stuff and still have a tight sealing window?

@Jeff Leonas,

Yes you can provided

- that there is wood framing behind the fiber board and in the location that can catch the nail for the window nailing flanges.

- that the fiber board is in sufficiently good condition that it provides a uniform smooth surface. That is if sections of it are missing you may need to fill it in.

It sounds like you are installing your new windows into the rough opening and that the old windows have been completely removed.

In that case the best installation would be to provide housewrap on the siding around the window and to carry the house wrap up over the opening at the zoo at around the opening at the sides and top before installing the window into the opening.

Depending on your situation you may want to also take a look at the peel and stick window flashings discussed at this website.

Post a photo of your window opening and we can comment with more confidence and we may see something else worthy of note.

On 2023-06-11 by JOHN B - Match fiberboard sheathing thickness on a 1960s home

A 1960's bungalo. The sheathing is 3/4" fiberboard....under each course of 18" cedar shingle is a course of 5/16" thick 15-1/2" H fiberboard.

To trim the window there is really not a viable 5/16" thick substitute replacement. These days the minimum thickness available is 1/2".

On 2023-06-11 by InspectApedia Publisher - how to make a viable 5/16" thick substitute window trim replacement

Thanks for the question and photo. I gave this some thought and looked for 5/16" board products that might work to keep the repaired/replaced shingle siding at the same thickness as the original wall.

Those underlayment courses behind each shingle course that were originally fiberboard - a plant-fiber product, are indeed hard to find in most countries (where is your building?).

But you might be fine with any open-celled foam board product instead. An example is this polyether open celled stick-on foam board shown below, sold in 5/16" thickness at Blendor https://www.blenddoorusa.com/

Alternative 5/16" shimming/backing products might be found at Grainger who provides an EPDM Strip: Std, 1 in x 10 ft, 5/16 in Thick, Black, Closed Cell, 1-Sided Adhesive, Smooth

I also looked at rolls of foil faced foam insulation such as US Energy Reflective Foam Core Insulation (5/16 thick)
weatherization Kit Roll 16"x25' Meets All Fire Codes - that may also work but is a bit softer.

Key is to make the flashing around that new window perfect and perhaps to add some housewrap to be sure that any water brought out by the flashing is directed to the outside of the shingle courses below.

Here's the roll form of insulating sheet in 5/16" thickness - I am less sure about this because the foil forms a vapor barrier on the "wrong" side of the wall, though perhaps that's less of a concern where its use is very limited in total area.

On 2023-05-23 by Matt Quattlebaum - 3" thick insulating roof panels on old home in Georgia: contain asbestos?

Hello, I inspected the roof of this nursing home yesterday in Elberton, GA and found this almost 3 inch thick roof panel.

I am hoping to identify the specific product so I can advise on the best way to approach a new roof. I also need to determine if this product contains asbestos.

I have attached a picture.
Thanks!

I found out that the building was built in 1965. The roof side of this panel is covered by tar and gravel, and then a layer of foam insulation.

On 2023-05-30 by InspectApedia Publisher - 3" thick insulating roof panels from old buildings are usually a plant-based or wood-based fiberboard product

@Matt Quattlebaum,

Clues such as age of building and location (which you've given) can help answer some of your questions. And if you could see the back of the panels to look for any markings or colors, that would also be helpful in trying to identify the specific brand.

In our article

FIBERBOARD SHEATHING

you can see our example of a home in northern Minnesota (built in 1960) that used a similar 2 1/2" or 3" thick fiberboard roof sheathing that also formed the interior ceiling.

We also discuss some possible repair options in that same article.

As far as your asbestos question, the building age may help. If built after 1986, asbestos would not be a concern.

Read more about

ASBESTOS IN FIBERBOARD BUILDING SHEATHING & INSULATING BOARD

Usually those 3" thick insulating roof panels from old buildings are a plant-based or wood-based fiberboard product, though you'll appreciate that from a photo alone, without a specific manufacturer brand and product ID, one cannot be certain that the insulating board is asbestos-free without a lab test.

at FIBERBOARD CEILING & WALL COVERINGS

you'll see photos of a similar 3-inch thick fiberboard (non-asbestos) flat roof insulating panel that also formed the interior ceiling of a home.

On 2023-02-01 by Bill - Was asbestos used in houses in 1963?

Was asbestos used in houses in 1963?

3-02-01 by InspectApedia Editor (mod)

@Bill,

Yes, it was and in a number of products - from various types of flooring to ceiling tiles to siding and roofing, just to name a very few.

The years of asbestos use may vary by product but asbestos in flooring in the U.S. was discontinued after 1986.

This list of asbestos containing products is extensive, even if incomplete, and will give you some idea of the extent of use in asbestos in residential as well as commercial products.

MASTER LIST OF ASBESTOS PRODUCTS
https://inspectapedia.com/hazmat/Asbestos_Products.php

Question: what are these 3 inch thick x 2 ft x 8 ft fiber panels on the church roof?

2020/04/07 Michael Pryor said:

I have a old church chapel that we are roofing. It has vaulted ceiling with beams and has a 3 inch 2ft x 8ft type of fiber panel.

Any ideas on hat it is? Also the roof is shingle and nailed to it but it pulls right out easy. What's the best fix for this?

[Click to enlarge any image]

Reply: - fiberboard nal base on a roof

Michael

That looks like a fiberboard nail base use on roofs.

Before I pontificate about "fixing" something, please give me more details about just what problems you are seeing.

Is the nail base disintegrated or badly water damaged?

Is it basically intact?

Are you taking care not to step through the surface, especially in any areas that have been wet?

What are the country and city where this is located, and what is the age of the chapel?

Fiberboard roof substrate insulating panels are still manufactured and sold, but usually in much thinner 1/2" x 4 ft. x 8 ft. panels, such as this roof fiberboard panel currently available at Menards Building Suppliers in the U.S. [shown below].

This fiberboard roof substrate panel has an R-value of 1.3 and is moisture-resistant. This is not a structural panel.

On 2022-01-03 by john angel - what is the ceiling material in a 1950s mobile home?

im trying to figure out a ceiling material. im remoldeling a old mobile home from the late 50s and the ceiling needs repaired in two rooms and i cant determine what the material is.

i know its not small tiles,drop ceiling or vinyl covered.its not drywall,sheetrock,plaster,plywood and has a smoothe painted surface and large panels of some type.

would you have any idea to what i might be working with and i have only a laptop no way to get a picture.thanks

On 2022-01-03 by Inspectapedia Com Moderator

@john angel,

See if you can get a view of the edge of the material such as at a light fixture

On 2022-01-03 by john angel

@Inspectapedia Com Moderator, yes the edge of the ceiling looks brown,like a dark brownish

On 2022-01-03 by Inspectapedia Com Moderator

@john angel,

So indeed it may be one of the products on this page

 

On 2022-01-01 by Jeff Harrison - will fiberboard ceiling material burn?

Will old fiberboard used on ceilings from around the 60s burn completely up in a bonfire?

On 2022-01-02 by Inspectapedia Com Moderator

@Jeff Harrison,

Good question.

Our best information is at FIBERBOARD SHEATHING FIRE RATINGS

You'll see that some fiberboard products may have been treated for fire resistance so may not ignite readily but we warn about the combustibility of these materials and quote fire officials' opinions that they can contribute to building fires.

On 2021-07-21 by David - where to buy 2 3/8" thick roof decking fiberboard?

I am trying to source 2 3/8" thick fiber roofing decking that has a finished side which appears to be a white vinyl sheeting like wallpaper. It is in an A frame home located in SE Pennsylvania built in 1976.

On 2021-07-21 by inspectapedia.com.moderator

@David,

We have examples of such products including thick fiberboard roof decking that also forms the interior ceiling finish in a northern Minnesota home from the 1960s - similar to what you describe

Illustrated and described at FIBERBOARD CEILING & WALL COVERINGS

https://inspectapedia.com/interiors/Fiberboard-Ceilings-Walls.php

In these cases the thick fiber roof decking is serving multiple functions:

• fiberboard roof deck
• fiberboard insulation
• interior ceiling finish
  

In the FAQs for that page and this one you'll see other readers approaches to replacing sections of ceilings or roofs where these products were used

On 2020-10-18 by John - identify this insulating board from fragments?

Hi, here is another image of the board. Thank you

On 2020-10-18 by danjoefriedman (mod)

John:

I see in your photo what looks like

- wood fiber material (cellulose fibers) brown, coarse, in the photo bottom

- gray fibers that may be a wood or paper product combined with what look like small flecks of white - is that styrofoam or hard plaster? - faced with a black, apparently sticky coating characteristic of water-resistant coatings used on many fiberboard products

You'd need a lab analysis to be sure of the makeup of these materials

On 2020-10-18 by John

Thanks again Dan. There were two types of boards. Just wanted to make sure the one in question is the one that is white and has a lot small white pebbles/sand like stuff. Best.

On 2020-10-18 by danjoefriedman

John

Trying to zoom in the photos are both a bit blurry so I am not sure what fibres we are seeing. Most likely they are either a mineral fibre or a cellulose or plant fibre.

 

On 2016-08-28 by Savannah - 1920s wallpaper or "wall covering" on plaster contains asbestos?

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 2016-08-28 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: 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)
• 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 2016-01-24 by Woody - Old Celotex lath fiberboard - contained asbestos?

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

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.

...

Continue reading at FIBERBOARD SHEATHING IDENTIFICATION KEY - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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• SHEATHING, EXTERIOR PRODUCT INDEX

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