Carpet Padding Asbestos, Mold, Odors, IAQ


Modern carpet padding materials
Antique carpet padding & underlayment
Identify & Cure These Carpet Worries

Does Carpet Padding Contain Asbestos?

Some readers ask if carpet padding is likely to be an asbestos hazard in buildings, as we discuss and illustrate here.

Example: "Does asbestos flooring or carpeting underlayment resemble foam? Is it a paper like product?" - reader question from D.G.

Answer: 

Bottom line: residential carpet padding does not contain asbestos. With rare exceptions cited below, we have not found reports of foam carpet padding deliberately made of asbestos nor paper.

However asphalt impregnated felt sometimes used as carpet underlay or underlayment may contain asbestos if it was manufactured before your country banned or stopped that usage. (Overbury 1925 et als).

Details:

Some carpet padding looks like and may actually use forms of spongy foam products - that's not an asbestos material.

Other carpet padding may use natural fibers such as jute or may be felt.

But as you phrased it, "Asbestos flooring underlayment or carpet underlayment" No, that is not a residential carpeting product.

Watch out: Some other flooring products used for an underlay or as a backer an asphalt impregnated felt ("paper") that may, depending on when and where it was manufactured, contain asbestos, as did some flooring adhesive mastics.

Felt underlay or underlayment is not, in my OPINON actual carpet padding but it may indeed be found beneath carpeting in some buildings. (UK HSE 2012).

Case Report of Asbestos-Contaminated Carpet Padding in Australia

Watch out: in older homes in Australia, carpet padding may have been produced by recycled bags used by James Hardie corporation to transport asbestos fibers, creating an unexpected potential asbestos hazard in those homes.

Also in Australia, both driveways and garage floors of some homes built in the 1970's may have contained asbestos waste from James Hardie.^[1]

There were however many other that used asbestos paper such as HVAC duct wrap and asbestos backing on sheet flooring.

Please keep in mind that no one can assure by email that your property has no asbestos present.

If the property age or other conditions raise an asbestos concern, you should have a professional inspection and tests performed before demolishing or disturbing any asbestos-suspect material.

See our articles on asbestos products in buildings including

ASBESTOS IDENTIFICATION IN BUILDINGS

ASPHALT ROOF MATERIAL ASBESTOS

and see

CARPET DUST IDENTIFICATION

Details about Asbestos in Australian Carpet Padding

An exception of asbestos-contaminated carpet padding has been reported in Australia, creating a public stir, but a subsequent investigation by Jim Dodd, Director of Environmental Health, reported that the possibility of asbestos fibres being in carpet underlay was very low. [1][2][3][4]

People most at risk were those working in the bag recycling industry^[4] when hessian (burlap or jute) bags used to transport asbestos material were recycled. Western Australians concerned about possible asbestos in their carpet underlay should first identify the type of carpet padding used: for example if it is a foam product it was not made from recycled bags.

Quoting from ASBESTOS in CARPET UNDERLAY [PDF] (2009), from the Western Australia DOH,

There is a slight possibility that some older hair felt-style underlay manufactured and installed prior to the early 1970s may have incorporated material sourced from hessian bags that were used to transport raw asbestos from mine sites to processing plants.

... believed to have been installed prior to 1970 ... in Perth homes. ... Of the 12 homes tested, one has proved positive for asbestos. ... Of the 12 homes tested, one has proved positive for asbestos.

It has been ascertained that the carpet and underlay in the affected home was installed in the early 1950’s. Further testing of underlay, carpet and dust from rooms in the home in which the affected underlay was situated indicates that the asbestos fibres remained within the underlay.

It therefore appears that the risk of fibres becoming airborne and presenting a health risk is very low provided the carpet and underlay remain undisturbed.

The DOH offered this good advice for removing old carpeting and carpet padding or underlay:

... it is advisable to wear a Class P1 or P2 disposable facemask (available at most hardware outlets) and disposable overalls if you are intending to remove old carpet with hair felt underlay (pre 1970).

This will provide protection against inhaling dust and other allergens as well as any asbestos fibres in the unlikely event they are present.

The carpet and underlay should be carefully, removed to minimise release of dust and particulates. It is advisable to lightly wet down the underside of the carpet and underlay prior to and during removal. This will help to suppress dust.

Owners concerned about possible asbestos in their fiber-based carpet underlay should contact an accredited asbestos testing laboratory.

List of Carpet Padding Materials

Normally carpet padding is constructed of man made or natural fibers, rubber, or urethane foam products.

Unlike the backer on some resilient flooring products or sheet flooring, carpet padding would not normally contain asbestos.

Carpet padding materials are typically felt carpet padding (photos above), foam carpet padding (photos below), or synthetic fabric bonded to a foam underlayment.

Fiber carpet cushions or pads

Fiber type carpet padding (above) may be made from natural fibers (such as jute, felt, or even horsehair), synthetic fibers (acrylic fibers, nylon fibers, polyesters, propylene fibers), or recycled textile fibers that may be a mix of natural and synthetic materials.

Bonded Synthetic Fabric & Foam Carpet Padding

Our photos below illustrate a durable carpet cushion that combines a dense synethetic fabric with a urethane foam cushion.

While this material is sold for use under wall-to-wall carpeting, we also use this padding cut to size for placement under area rugs where we want a firm walking surface and an anti-slip property to prevent the rug from moving.

Bonded Urethane Foam "Rebond" Carpet Padding

The carpet padding photographs below show a bonded urethane foam product also referred to as "rebond" because it is made of chopped or shredded foam that has been re-bonded together to form a sheet.

Above you can also see the bonded coated backing of the carpeting itself - the white-coated carpet bottom at the right side of the photo.

Our second rebond padding photo (below) shows us exposing the subfloor below the padding in an area where the homeowner had already made carpet and padding cuts to inspect for water leakage.

Here you can see that the rebond carpet padding is also reinforced with synthetic fibers.

Because some rebond, especially made in the U.S. before 1985, may contain butylated hydroxytoluene (BHT), this padding type can cause yellowing of olefin and some nylon carpets and is not recommended below those products.

Two other foam carpet padding materials are prime urethane foam and mechanically-frothed urethane foam.

Rubber carpet padding materials are typically seen in one of two forms: waffled sponge rubber and a more firm flat sponge rubber. Flat sponge rubber is used below commercial and berber carpets.

Antique & Historic Carpet Underlayment, Lining, Padding

Wanamaker's Sanitary Carpet Lining

In older homes and some historic properties where very old carpeting remains, you may find paper-based Sanitary Carpet Lining that was sold by The Wanamaker Store (photographs below).

We are uncertain of the composition of this material, but you are highly unlikely to encounter it except in an antique building. Wanamakers, a Philadelphia PA store, began 1880, selling carpets and carpet liners in 1880.^[2]

Note: The John Wanamaker Store in King of Prussia, PA. has been cited by some asbestos-exposure and mesothelioma websites as a source of asbestos exposure to workers. We have not [yet] located a description of how that exposure occurred or what products were involved.

Moldy or Smelly Carpeting & Carpet Padding Odors

If you trace a moldy odor or smell to the carpeting or its padding beneath, chances are that it is or was moldy.

Wet carpeting and carpet padding can become moldy in just 48 hours or so, depending on building temperatures and extent of water intrusion so it's difficult to salvage wet wall to wall carpets or carpet padding even if only part of the carpet got wet.

Watch out: Carpeting that has been wet usually is removed along with its carpet padding and disposed of, though we have found a few cases in which carpet that was reported to have been wet was dry, un-stained, and clean at the time of our inspection.

There are other reasons to remove padding below moldy or wet carpets, particularly the need to inspect the floor and floor-wall trim for signs of water, mold, damage and to permit additional cleaning.

It's generally the case that a soaked carpet will also leave water marks on the subfloor below. But if water has entered the building wall cavities further investigation is warranted, lest we leave a mold reservoir in building walls.

Watch out: don't try to fix moldy, smelly or previously-wet carpet padding by spraying with a disinfectant or sanitizer nor by using an ozone generator. Those treatments are not reliable and in some cases can make mattes worse.

Details are at CARPET OZONE MOLD / ODOR TREATMENT WARNINGS

If your carpets look clean and you don't know of any history of wet carpeting, and so if you're not sure if a mold or other odor is coming from the carpet or carpet padding or from somewhere else,

see SMELL PATCH TEST to FIND ODOR SOURCE

Carpets or Carpet Padding & VOCs or MVOCs

As we discuss at CARPET MOLD / ODOR TESTS, mold may be visible on the surface of carpeting or mold may be hidden in carpeting or in the padding or carpet cushion below.

Carpets may not actually be mold contaminated but can smell moldy if the carpeting or padding have absorbed Mold-related volatile organic compounds or MVOCs. In this case we suspected that the visible carpet mold was the "tip of an iceberg" of hidden mold below.

More about dealing with wet or moldy carpeting is in articles listed at

• CARPET STAIN DIAGNOSIS - home
• CARPETING & INDOOR AIR QUALITY - home

Research on Asbestos in Carpet or Carpet Underlayment

• [1] "James Hardie's Mesothelioma and Asbestos Legacy Continues, 2009", web search 03/01/2011, www.survivingmesothelioma.com
• [2] "The Business Biography of John Wanamaker Founder and Builder, America's Merchant Pioneer from 1861 to 1922", web search 03/02/2011, original source: http://www.archive.org/stream/businessbiograph011556mbp/businessbiograph011556mbp_djvu.txt
• [3]"Western Australia Health Department Warns on Asbestos in Carpet Pad", Perth Now, Australian Broadcasting Company, 24 March 2006
• [4]"Old Carpet Underlay Unlikely Asbestos Risk", 11 July 2006, see http://www.health.wa.gov.au
• ASBESTOS in CARPET UNDERLAY [PDF] (2009) Department of Health, Government of Western Australia, Rev. 3 December 2009, web search 03/03/2011, original source: http://www.public.health.wa.gov.au/cproot/2463/2/Carpet%20Underlay%20Update_2_.pdf
  Excerpt:
  
  In response to the original concerns in 2006, the Department of Health’s (DOH) Environmental Health Directorate (EHD) had several samples of carpet underlay tested to try and obtain actual evidence of asbestos fibres in underlay of homes.
  
  The intention was to obtain samples of underlay that had been installed before 1970, but ideally, ‘original’ underlay.
  
  Although only a relatively small number of samples were able to be obtained, all were found to be free of asbestos.
• Asbestos in Carpet Underlay, Frequently Asked Questions, , Department of Health, Government of Western Australia, Rev. 3 December 2009, web search 03/03/2011, original source:
  http://www.public.health.wa.gov.au/cproot/2462/2/Carpet%20Underlay%20FAQ%20Update%20_2_.pdf
• Carpet fibers and padding, Kathryn A. Hairle, [may be unavailable], University of Wisconsin Cooperative Extension, 1975
• Handbook of Fiber Finishing Technology, Philip E. Slade, 1997, [Quoting Amazon.com]
  
  Gathering hard-to-obtain data from different fiber and fabric manufacturers and suppliers into a single, convenient volume, this practical handbook supplies detailed information on hundreds of textile finish components;including their structural formulae, physical properties, CAS numbers, and effects on various fibers.
  
  Promoting a deeper understanding of finish technology, the Handbook of Fiber Finish Technology covers the fundamentals of fiber finish science, such as theories of friction laboratory testing of formulations from preliminary component evaluation to analyses for material characterization the influence of wetting, emulsification, and finish distribution on coatings soil- and stain-resistant chemicals and their applications in carpet protection the degradation of chemicals in the environment, including methods for predicting waste degeneration and more!
  
  Complemented with bibliographic citations and nearly 500 tables, equations, and drawings, this expertly written handbook is invaluable for polymer, fiber, and textile chemists, scientists, and engineers; physical, surface, and colloid chemists; textile and fiber manufacturers; and graduate-level students in these disciplines.
• Overbury, Frederick C. "Process of making roofing felt or like material." U.S. Patent 1,558,495, issued October 27, 1925.
  
  Abstract excerpts
  
  What I claim is The herein described method of producing-a flexible composite sheet of fibrous material, consisting in bringing into face contact two layers of wet pulpy felted fiber and asbestos fiber, causing the said fibers of said layers to interlock, and then drying the sheet thus formed.
  
• Rug and carpet fibers: Selection and Care, Shirley M. Niemeyer
• Rugs and Carpets - Padding, Patsy Keller, [may be unavailable],
• Rug pulled out from recycling: carpet padding recycling is taking a big hit ...(polybrominated diphenyl ethers presence, Ed Thornhill, Construction & Demolition Recycling (Magazine/Journal), 2005
• Tufted Carpet: Textile Fibers, Dyes, Finishes, and Processes, Von Moody, Howard L. Haber, [Quoting from Amazon]
  
  This book combines Von Moody's original work and research in the carpet industry with the well respected 1986 textile source book, Textile Fibers, Dyes, Finishes, and Processes: A Concise Guide, by Howard L. Needles to produce a unique practical guide on all aspects of the preparation, manufacture, and performance of carpet.
  
  It addresses the structure and properties of fiber, carpet construction, coatings, dyes, finishes, performance, and recycling, among other topics. This volume is an indispensable reference for all practitioners in the carpet industry.
• U.K. Council, Balranald Shire. Asbestos Policy [PDF] (2018).
  
  Excerpt: Asbestos can be found in carpet underlay p. 32
• U.K. HSE, Books, H. S. E. ASBESTEOS, THE SURVEY GUIDE [PDF] (2012). ISBN 978 0 7176 6502 0 U.K. Health & Safety Executive, HSE, - retrieved 2024/08/01, copy on file as Asbestos-Surveys-HSE-2012.pdf - This is a free-to-download, web-friendly version of HSG264 (Second edition, published 2012). This version has been adapted for online use from HSE’s current printed version. You can buy the book at www.hsebooks.co.uk. ISBN 978 0 7176 6502 0 Price £17.50
  
  Excerpt:
  Flooring products 15 Polyvinyl chloride (PVC or vinyl) tiles were manufactured with added asbestos to meet a British Standard and often contain a few per cent (5–7%) of very fine chrysotile. Black and brown thermoplastic tiles containing larger amounts and often visible clumps of chrysotile were also produced.
  
  Sheet floor coverings were sometimes backed with a thin layer of chrysotile paper (eg ‘Novilon’, a vinyl flooring, which was more common in Europe).
  
  Some underfelts for carpets and linoleum were also manufactured containing asbestos.
  
  The mastics which were used to bond the floor covering to the surface could also contain asbestos. Some hardwearing composite floors (eg magnesium oxychloride) also contain about 2% of mineral fibres which could be asbestos.