Asbestos in homes

We get a lot of questions from home buyers about asbestos. Will we identify the presence of asbestos? Can we test for asbestos? Does this or that material contain asbestos? And so on. During one of our recent monthly home inspector meetings for the ASHI Heartland chapter we had an industrial hygienist from Legend Technical Services, my go-to company for asbestos testing, come out to teach a class on asbestos and asbestos testing. At the end of the class, our teacher concluded with something that I'm going to share right at the beginning of this blog post: If a material is not made from wood or metal, it might contain asbestos.

That might be a slight exaggeration, but only slight. After going through the list of products in the class, the only way that I would feel comfortable telling someone that a product does not contain asbestos would be if it was made from wood or metal. Asbestos has been used to create over 3,000 building products. Three Thousand. Even lab testing isn't always enough to confirm that a product doesn't contain asbestos; check out my recent blog post on vermiculite insulation. I can't possibly cover everything, but here's a list of products that always or almost always contain asbestos, and are usually quite easy to identify.

Cement-asbestos siding  It looks like a cross between cedar-shake siding and newer fiber-cement siding. It's fairly brittle stuff, and most houses with this type of siding will have a few damaged or cracked pieces.

damaged cement asbestos siding 2

Damaged cement asbestos siding

Transite asbestos furnace flues  I blogged about these a couple of years ago, and I put together a big compilation of photos in that post: Transite Asbestos Flues.

Transite Asbestos Flue, Minneapolis home built in 1954 (#1)

They're typically bad news because they have a tendency to flake apart and collapse, which can create a serious safety hazard.

Transite asbestos in-floor ductwork  Usually when people refer to "transite heat", they mean there is ductwork installed below the basement slab for air to travel through. The most common product is PVC, but transite-asbestos ductwork was also used for this. It's very easy to tell the difference; just pop off a floor register cover to take a look at a cut edge.

Transite Asbestos heat close-up

Transite Asbestos heat

Transite asbestos is whitish and has a cementitious look to it.

And yes, cementitious is a word. It means exactly what you think it means.

Boiler pipe and water pipe insulation that has a cloth look on the outside and a cardboard look on the ends

When it looks like the stuff shown below, it could easily become airborne.

Friable asbestos on boiler pipes

This next photo shows insulation that isn't in great condition, but isn't nearly as bad as the stuff above.

Cold water piping wrapped with possible asbestos material

This next photo shows asbestos insulation that's in good condition. It's even labeled. Isn't that convenient?

Asbestos boiler pipes

Some people like to put warning labels on this material. Probably not a bad idea.

Asbestos insulation on pipe wrap

Insulation on old boilers and gravity furnaces  The boiler and gravity furnace shown below are both covered in insulation known to contain asbestos.

Old Boiler

Gravity Furnace

White fibrous insulation on furnace ductwork  Most of the insulation on this ductwork has been removed, but there is still a little left.  This material is known to contain asbestos.

Fibrous insulation on ductwork

9" x 9" floor tiles and the adhesive used to keep them in place  It's typically safe to assume that 9" x 9" floor tiles contain asbestos, and that 12" x 12" don't, but that's only an assumption.  There are no guarantees.

Bonafide Vinyl Asbestos Tile

Vermiculite insulation  Again, see my recent blog post on this topic: vermiculite insulation.

Vermiculite Insulation

Those are the products that are commonly known to contain asbestos, but the list of product that might contain asbestos goes on forever. Here's a small part of that list, used primarily in buildings before 1980:

  • Linoleum floor covering
  • Sprayed-on insulation, typically found on ceilings or beams for fire or sound control
  • Ceiling tiles
  • Wall and ceiling plaster and texturing
  • Drywall, taping compound, drywall mud, and ceiling texture (popcorn ceilings)
  • Fire blankets, curtains, doors
  • Roofing
  • Spackling
  • Caulking and putties
  • Electrical panel housings
  • Sink undercoatings
  • Ceramic tile
  • Thinset / mortar
  • Grout
  • Flooring adhesive

What to do about asbestos

If you're buying an old home, it's probably safe to assume that you're buying a home contains some products that have asbestos in them. In most cases, it's not a big deal. Asbestos doesn't do any harm as long as it remains intact and nobody breathes in the asbestos fibers. Follow the advice from the EPA and the CPSC: if asbestos-containing materials are in good shape, leave them alone. The one exception to this might be vermiculite insulation, simply because there is money available to help homeowners with the costs of vermiculite insulation removal, and because the asbestos fibers in vermiculite can be released into the air just by looking at them wrong.

Oh, and for the record, my company does not test for asbestos. When a client wants asbestos testing performed, we refer the above-mentioned company, Legend Technical Services. Home inspection standards of practice specifically exclude the identification of environmental hazards, such as asbestos. Nevertheless, most home inspectors that I know will point out the stuff shown in my photos above, because these materials are fairly easy to identify and all of these materials are very likely to contain asbestos.

For a list of asbestos abatement contractors in Minnesota, click the following link: MN Asbestos Contractors and Consultants.

Author: Reuben SaltzmanStructure Tech Home Inspections


Written By

Reuben is a second-generation home inspector with a passion for his work. He grew up remodeling homes and learning about carpentry since he was old enough to hold a hammer. Reuben grew up thinking he was going to be a school teacher because he enjoyed teaching others so much. In a sense, that’s a lot of what home inspections are about, so Reuben truly does what he loves. Sharlene has worked with Structure Tech since 2000 and Reuben has been contributing to her blog since 2008.

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