Asbestos containing acoustic ceiling tilesCatalog of Celotex® Insulating & Sheathing products that contain asbestos or that are asbestos-free

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Asbestos-containing products made by the Celotex corporation.

The following list names and comments on building products such as ceiling tiles and many other Celotex® brand building products & articles listed by some sources as believed to contain asbestos.

This article series assists building buyers, owners or inspectors who need to identify asbestos materials (or probable-asbestos) in buildings by simple visual inspection. We provide photographs and descriptive text of asbestos insulation and other asbestos-containing products to permit identification of definite, probable, or possible asbestos materials in buildings.

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Alphabetical list of Celotex™ insulating & other building products believed to contain or not contain asbestos

Asbestos containing acoustic ceiling tiles

[Click to enlarge any image]
  • Acoustical Systems & Sound Control Systems [1]
    • Acoustical ceiling panels. Notes: Asbestos fibers were used in some acoustic asbestos ceiling tiles, often amphibole asbestos such as amosite, crocidolite, anthrophylite, tremolite, and actinolite, with amosite among the most commonly-found. Modern ceiling products do not contain asbestos.
    • Insulating panels.
    • Celotex Brand ceiling tiles - [Suspended ceiling tiles of the 2'x2' or 2'x4' dimension, and manufactured by Armstrong, Celotex, Conwed, LoTone, and USG and made before the late 1970's are listed by several attorney-sponsored "mesothelioma websites" as often containing asbestos to add fire-resistance. On that basis, if the age of your ceiling is in that range it would be prudent to treat it as PACM.[9] Confirmation of asbestos content use & dates pending - Ed.]

Celo-Siding Celotex siding board (C) InspectApedia op cit 1943

  • Cane fiber products [Cane products were not an asbestos-containing product, though some may have been manufactured at facilities where asbestos was present - Ed.] Citation [2] at REFERENCES
    • Celotex sheathing [See Cemesto below]
    • Celotex insulating lath (board) [this is probably a cellulose fiber insulating board; separately a gypsum based rock-lath was also produced]
    • Celotex interior finish
    • Celo-Siding [a cellulose fiber insulating board product]

Celotex gypsum board interior wall system in 1943 (C) InspectApedia original source Architectural Record 1943 p. 16

  • Celo-Rok Gypsum products - gypsum based sheathing boards used on walls & roofs both as finished surface produccts and as a base for plaster application. [some gypsum-based drywall as well as drywall compound may contain asbestos]: Citation [2] at REFERENCES
    • Celo-Rok anchor lath,
    • Celo-Rock wallboards,
    • Celo-Rok plasters

Celotex asbestos board (C) InspectApedia op cit 1943

  • Insulating building panels or "fiberboards - [Fiberboard is generally a wood-fiber productd
    See FIBERBOARD SHEATHING, Celotex Homasote & Other , but someproducts listed here include fiber-cement materials, probably due to confusion among attorneys who have erroneously lumped these materials together - Ed. ] Also
    • Celotex Cemesta products [2] - properly spelled Celotex Cemesto - see the Cemesto advertisement below. At least some Cemesto sheathing boards incorporated a layer of cement-asbestos board for both exterior and interior finish purposes. See the Cemesto advertisement and properties illustrated below.
    • Thermo-board
    • Carey Flex Board
    • Carey Millboard

Cemesto building panels from Celotex (C) InspectApedia op cit 1943

  • Carey Asbestos Mine Celotex Products: Other Building insulation products including products directly associated with the Celotex-owned Carey Asbestos mine in Canada and containing asbestos include the following:
    • Carey 7-M Asbestos Shorts
    • Carey Block Insulation
    • Carey Cemesto board [appears in some citations as"Carey Cenesto board"]
    • Carey firefoil board & panels
    • Careyflex board
    • Careytemp masonry block insulation and blocks
    • Carey Industral A/C boards
    • Carey Insulating Cement
    • Carey Marine Panels
    • Carey Stone corrugated sheets used for roofing & siding
    • Carestone roofing & siding, Careystone wall sheathing & baffles
    • Carey Thermalite
    • CareyTemp insulating cement
    • Carey MW-50 Insulating Cement
    • Celobric insulating brick siding & Celobric "buff blend textured"
    • Vitricel asbestos sheets
  • Building plumbing products

Celotex gypsum roof panels (C) InspectAPedia 1943 op cit

History of the Celotex Corporation: Background on Celotex & Asbestos

Celotex product description from 1943, Architectural Record October 1943 p. 16 -

  • 1921: Celotex Corporation Founded in the U.S. with Celotex Company of Great Britain established in the same decade. Importer of bagasse fibergoard used to make a variety of wood-cellulose-based insulating sheathing products.
  • 1938: Celotex assumes control of Certain Teed building products
  • 1943: Celotex wood fiber board and gypsum board products saw increasing use in construction due to the scarcity of building materials during WWII. At Left: advertisement for various Celotex sheathing board products as appearing in Architectural Record, October 1943, p. 16.
  • 1944: in proxy fight R.W. Liazars takes control of CertainTeed from Celotex.
  • 1964: Celotex purchased by Jim Walter & reincorporated as Celotex Corporation of America.
  • 1970: The Celotex Corporation of America introduced an isocyanurate foam ceiling tile [11] (not an asbestos-containing product). By this year, asbestos was widely used as fireproofing in roofs, floors, ceilings.[28]
  • 1986: Celotex-owned Carey Canada Inc., asbestos mine closed.
  • 1989: U.S. Jury award to Marion George in lawsuit concerning her husband who worked as an asbestos insulation contractor/distributor
  • 1990: Celotex bankruptcy filing, 12 October 1990
  • 1996: Celotex Corporation reorganized, 9 December 1996
  • 1997: Celotex Corporation reorganized
  • 1998: Celotex trust fund created ($1.246 million). Claims against Celotex and its asbestos mining subsidiary Carey Canada for asbestos exposure and mesothelioma claims.
  • 1999: US EPA Asbestos Materials Bans: Clarification. This document makes clear that EPA has no existing bans on asbestos-containing products other than items listed in this document: ACM ceiling tiles were not banned. Note: however because of public resistance to purchase or use of ACM products, many manufacturers discontinued of asbestos in various products, particularly after 1976. Check the individual product MSDS for confirmation of its content. - Ed. In this year Great Britain banned the sale or re-use of white asbestos. [26]
  • 2000: BPB PLC of the U.K. purchased the Celotex ceiling and wallboard operations
  • 2000: CertainTeed acquired Celotex Roofing.
  • 2012: Celotex Corporation continues operations in the U.K. selling foam board (polyisocyanurate foam) insulation.
  • See ASBESTOS MATERIAL REGULATIONS for a history of asbestos bans, regulations, laws

While an expert lab test using polarized light microscopy may be needed to identify the specific type of asbestos fiber, or to identify the presence of asbestos in air or dust samples, many asbestos-containing building products not only are obvious and easy to recognize, but since there were not other look-alike products that were not asbestos, a visual identification of this material can be virtually a certainty in many cases.

See ASBESTOS FIREPROOFING SPRAY-On Coatings for photos of dangerous tremolite asbestos ceiling panels and photos of spray-on asbestos fireproofing coatings.


and see ASBESTOS DUCTS, HVAC a field identification guide to visual detection of asbestos in and on heating and cooling system ducts and flue vents.

Also see Micro-Photographs of Dust from the World Trade Center collapse following the 9/1

What is Celotex Insulating Lumber? Did it contain asbestos?

Celotex insulating lumber Reader question: I have a home built in 1940 that used a brown fiber board called "Celotex Insulating Lumber" looks like is was designed to be used as sheathing and lath. Made in either Chicago on Louisiana. Anyone familiar with this? Or know if it contained asbestos? - Dan Theisen 1/30/12


Dan, Celotex, a Chicago company, has been a producer of a wide variety of insulating sheathing boards for a long time and the company continues to produce modern insulating board products as well.

Our illustration (left) shows Celotex insulating lumber on the exterior of a Lebanon PA home. This insulating board is a wood-fiber product (actually made of bagasse fibers obtained from sugar cane, that is, cellulose) that we document in detail at SHEATHING, FIBERBOARD.

Asbestos was not among the product's ingredients. Only if such products were produced at a manufacturing facility that also produced asbestos-containing products might there have been a risk of cross-contamination that could result in the detection of asbestos in the cellulose-based materials.

Reader Question: asbestos in Celotex Gypsum Board (drywall) 4X8 panels?

Celotex tapered edge drywall gypsum board (C) InspectAPedia5/21/2014 Jesse said:

I am buying a house that has unused Celotex Gypsum Board (drywall) 4X8 panels in the basement... the owner has offered to leave them for me to use when I finish the basement, but I don't know if they contain asbestos and can't find an answer online.


Jesse if you refer to celo.rock gypsum panels, some of those may indeed contain asbestos. Use the CONTACT link found at the bottom of any InspectApedia web page to send me sharp photos of both sides and an edge of the product and of any stampings or markings and I can comment further.

On receipt of photo (above) This looks like a quite recent tapered edge product. If so it would not be expected to contain asbestos. Do you know when it was bought?

Reader follow-up:

The gentleman I'm buying it from says it is 10-15 years old... so '99-'04 would be my best guess. The house was built in '9.. so definitely bought after then.


sounds fine

Reader Question: Does this 1968-era Celo-Rok® Gypsum board contain asbestos?

Celotex Celo-Rok gypsum board (C) InspectApedia SQ Celotex Celo-Rok gypsum board (C) InspectApedia SQ

I was so happy to locate your site. We are remodeling our inherited mom's house and have a whole lot of drywall to replace. We really need to find out if it contains asbestos. I think I located the name of it on your site but it says 'May contain asbestos'. I have attached a couple of pictures in hopes that you could help identify and determine for us.

The drywall is Celotex Celo-Rok® gypsum board.

Thank you so much for any help you can provide. - Anon [by private email] 19 Sept 2015


Celo-Rok Catalog cover 1947 (C) InspectApediaAside from product labeling and visual appearance, it would be most helpful if we knew the age of the home and age of the wallboard or about when it was installed.

Certainly Celo-Rok products from the 1940's were advertised as containing asbestos in some of that product line. However your photographs, the paper taping edging on the drywall panels, and the blue ink numeric stamp all look to me like much more modern products than those from the 1940's.

Celotex Celo-Rok® gypsum products were widely sold in the 1940's. However from my reading of the advertised properties of Celotex products (from 1943) it is clear that the company did not explicitly name asbestos as an ingredient in all of its sheathing products.

In addition to the 1943 Celotex advertisement cited in this article, I note that an advertisement for books on asbestos cites and quotes a 1947 Celo-Rok product catalog produced by the Celotex Corporation [shown at left] that refers to "Wood or Asbestos Shingles" (the latter would have properly been called asbestos-cement shingles) as a roof covering beneath which a Celotex Celo-Rok roofing panel might be applied.

The use of the word "asbestos" in referring to roof shingles is perhaps a source of confusion about asbetos as an ingredient in Celo-Rok®.

Similarly, "How You Can Build Better Homes at Lower Cost", from the same era cites:

Important contributions to "Economy Home" construction are the new types of patented fasteners specially developed for
applying wood or asbestos shingles directly to Celotex Insulating Sheathing.
One section of Glen Oaks Village in Bellerose, Long Island, N.Y., built by Gross-Morton of Jamaic or L. I., N. Y. There are 3800 apartments in this huge, beautiful garden-type development. Celotex insulating Sheathing used throughout. C. A. Hemphill Associates, Evanston, Illinois, used Celotex Insulating Sheathing on these fine homes in Forest Glen subdivision, Winnetka, III. - retrieved 21 Sept 2015 original source: /HowYouCanBuildBetter HomesAtLowerCost/HowYouCanBuildBetterHomesAtLowerCost_djvu.txt

In the 1940's Celotex produced and marketed "Celo-Rok Anchor Lath" as a substitute for traditional wood lath in wall plastering applications. The company produced a "cane-board" lath product as well.

These texts do not cite asbestos in the sheathing or lath product itself.

I suspect that your gypsum wallboard does not contain asbestos, though I do not know that for a fact. My reasoning is that at least into the 1960's the use of asbestos in building products was considered a positive feature as it added both strength and fire resistance. It was common for a manufacturer to include asbestos and its properties in product literature and in product advertisements.

Bottom line: to know for certain if your specific Celo-Rok wallboard contains asbestos you'd need to send a sample to a certified asbestos testing lab.

As it's quite inexpensive, and as it could make a significant difference in the cost in an extensive renovation work where all drywall is being removed, I would have a lab test performed to confirm the presence or absence of asbestos in your 1960's vintage Celo-Roc. That's because:

  1. We have not found unequivocal data clearly stating the presence or absence of asbestos in interior gypsum board produced with the Celo-Roc brand
  2. If you found asbestos in a dust-creating material that was going to be removed during extensive demolition and that couldn't be removed with practically no debris and dust production, an asbestos-dust-containment job will be much more costly than straightforward demo of asbestos-free drywall.

If you take that action (about $50. U.S.) you can send me the bill and in any case I ask that you keep us informed of a test result as what you learn will help other readers.

References & Research on Asbestos in Celotex Products

  • Bruce, Daniel C., "Composition of matter." U.S. Patent 1,804,245, issued May 5, 1931. The putty described by this invention was comprised of water, flour, borax and glycerine as well as a hydrocarbon such as gasoline or kerosene or benzene to form a preservative soap emulsion.
    This invention relates to a composition of matter and it is an object of the invention to provide a composition of a soft putty consistency and which is particularly intended 5 to be used as a filler in connection with the application of commercial wall board manufactured from fibres obtained from cane, asbestos, wood, flax, straw, or other absorbitant fibres such as, and including, the wall 1 board now used and manufactured and known as Celotex, Beaver board, Sheetrock, Best-wall, Masonite, Insolite, Gypsolite, Rockboard, Cornell, or Upson wall board, and other boards made from cane, asbestos, wood, flax, straw, or gypsum. Another object of the invention is to provide a composition of this kind which is particularly intended for use in the filling of joints, covering nail heads and coating the surface of wall board, etc. An additional object of the invention is to provide a composition of this kind which is adapted to produce an invisible joint; to take the place of plaster, coating, or paint; and upon the omission of fibrous matter to produce a liquid composition for sizing walls before the application of paint or wall paper. ...
    There is then added one pound of comminuted fibres taken from cane fibre or Celotex wall board fibres obtained from asbestos, wood, straw, or other absorbitant fibres. These fibres are thoroughly mixed with the admixture and kneaded until it forms a putty-like product.
    In order to match the Celotex Wall board in color when cane fibres are used, suitable coloring matter soluble in water may be added to the first named admixture to obtain desired tints although ordinarily the composition when dry, owing to the action of the whiting or powdered chalk, causes the fibres to dry light in colorand thus prevent water stain[s].
  • Celotex, "Cemesto, Five Tested Ways to Meet Today's Building Needs with Minimum Use of Critical Materials", The Celotex Corporation, Chicago, Architectural Record, October 1943 p. 16 [Advertisement] The ad describes several Celotex wallboard and sheathing products including:
    • Celotex Asbestos Board builds walls fast. This new Celotex product is a hard, durable combin ation of portland cement and asbestos fibre, 3/16" or 1/4" thick, available in boards 4' x 8', for fast erection of interior walls and ceilings. Can also be used for exterior finish on temporary or permanent structures.
    • Celotex gypsum interior wall units save studding, save time. These extra-thick gypsum wall board are either 1" or 1 1/2" thick, and building strong, sturdy, good-looking interior parttions in the shortest possible time, with only a simple wood framework. Known as "single wall construction" this method saves much critical lumber.
    • Celotex insulating board sheathing comprised of 1/8" Cement-asbestosboard for exterior and interior finish, a water and vapor proof bituminous adhesive, Celotex Ferox-treated Cane-Fibre Insulation.
    • Cemesto, Cemesto combines strength, insulation, interior and exterior finish, sold in panels from 4' x 4' to 4' x 12'. "Cemesto is a revolutionary building material that comes in panels from 4' x 4' to 4' x 12' to provide a complete fire-retardant wall or roof unit. Thickness ranges from 1 1/8", 1 9/16" to 2". Today, Cemesto with 12 years of research behind it is speeding construction ofmillions of dollars' worth of wartime homes, housing projects, factories, shops and hangars using a minimum of critical material. Can be sued with either wood or steel framing. Saves time, labor, lulmber and nails.
    • Celo-Siding combines siding, sheathing, insulation. This new multiple function insulating siding consists of cane fibre insulation, coated on both sides with moisture-proof asphalt, with a weather surface of crushed mineral granules in colors to provide a permanent exterior finish. It is applied direct to studding. Two thicknesses 7/8" and 5/8".
    • Celotex Gypsum Roof Slabs replace wood roof decks. These new laminated gypsum roo9f deck slabs are offered in 1", 1 1/2" or 2" thicknesses, 2' wide, 8, 9', or 10' long, rigid, strong, light in weight and easy to handle. The big units cover roof areas quickly, saving important time. Roof covering can be applied immediately.
  • Sandberg, Lynn, "Celotex in Upper Michigan", Forestry Division, The Michigan Tech Forester, Forestry Club, Michigan College of Mining and Technology, Houghton MI, Vol XII (1961) pp. 16-17. [No mention of asbestos in this article.]
    For commercial installation, Celotex markets the well known line of Acousti -Celotex acoustical ceiling tile and suspension systems including economical fiberboard tiles, incombustible mineral fiber panels [possibly containing asbestos - ed] and efficient steelbase sound-absorbing tiles. The firm manufactures asphalt shingles, roll roofing and asphalt roofing felts.
    Celotex is also a major manufacturer and supplier of Celo-Rok gypsum wall board, sheathing and plaster; mineral wood insulating blankets and Handi-Pak home insulation; insulating siding; decorative interior hardboard panels and exterior hardboard siding; and indus rial fiberboard for a wide range of other applications such as packaging of delicate or irregularly shaped items and as a component of other products.
  • Tuscaloosa News, 14 June 1944, p. 7, classified ads, Excerpt: " For Sale - Make your own fan, limited lot ... Celotex celling tile board, Celotex insulation board, Celo-rock wall board for walls and celling, plaster, plaster lath. Kern-tone Miracle paint, ... All kinds of building materials. J. Oviatt Bowers Co., Phone 4456 14-3tp"
  • Also see the REFERENCES of this article for more citations


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