Asbestos Cement Siding: How to Identify It and Risks

Short answer: Asbestos cement siding is a hard, brittle shingle or panel made of cement with asbestos fibers mixed in, common on houses built through the 1970s. State health agencies say intact siding is generally not a hazard; the risk comes from breaking, cutting, drilling or sanding it, so any work on it should start with an accredited asbestos professional.

Check a specific house: asbestos cement siding or roofing is rated medium for homes built before 1981. Open the House Age Decoder with 1955 loaded →

What asbestos cement siding is

Asbestos cement siding (sometimes sold under trade names such as Transite, or described as “slate” siding) is made by binding asbestos fibers in cement. The fibers made the shingles strong, light for their size, fire-resistant and resistant to rot and insects. That made the product popular for exterior walls, and the same material was used for roofing shingles and trim.

EPA lists roofing and siding shingles among the household products that may contain asbestos. A consumer booklet from CPSC, EPA and the American Lung Association is more direct: some roofing and siding shingles are made of asbestos cement.

Which homes might have it

There is no clean federal cut-off year for siding. EPA’s broad 1989 asbestos ban, which would have phased out many asbestos products, was largely overturned by a federal appeals court in 1991. What did survive was a ban on new asbestos uses that began after August 25, 1989, and on a handful of specific paper and felt products.

In practice, use faded well before that. The Minnesota Department of Health notes that asbestos use in roofing and siding materials has declined rapidly since the early 1980s.

Year built	How likely	Notes
Before 1981	Possible (medium)	The main era of asbestos cement siding and roofing shingles.
1981 to 1989	Low	Use was declining; existing stock may have been installed.
1990 and later	Unlikely	Look at what the siding actually is; newer fiber-cement products look similar but are a different material.

Remember that siding is often replaced or covered. A 1950s house may now have vinyl over the original shingles, and the old layer can still be underneath.

How to recognize it

You can often spot the type of siding by sight. Whether it contains asbestos takes a lab test.

Feel: hard and rigid, like thin cement or stone, not flexible like vinyl or soft like wood.
Shape: flat shingles or panels installed in overlapping rows, sometimes with an embossed texture on the face.
Edges: brittle; chipped corners and cracks are common on older pieces.
Finish: usually painted, often in white, gray, green or pastel tones; weathered pieces can look chalky.
Under other siding: look at the edges of window trim, utility openings and the bottom course for an older layer behind vinyl or aluminum.

The Minnesota Department of Health suggests checking for markings, packaging or the manufacturer’s name, or having a certified inspector sample the material. If you do not test, it says to assume the material contains asbestos and treat it that way.

Modern fiber-cement siding can look almost identical. The build year, the age of the siding and any paperwork from the last re-siding job help, but they do not replace a test.

When it is a risk

The asbestos in this siding is locked into the cement. North Carolina’s health department explains that intact asbestos cement siding keeps the fibers bound and poses no hazard, but breaking or disturbing it can release fibers. Minnesota’s guidance agrees that simply having asbestos siding on your home does not pose a health risk, and adds that heat, water, weathering and aging can make the material more crumbly over time.

Work that can disturb it includes:

Cutting openings for new windows, doors, vents or electrical boxes.
Drilling to mount satellite dishes, lights, house numbers or awnings.
Nailing new siding over damaged or brittle shingles.
Sanding or scraping before painting.
Aggressive cleaning that abrades the surface. Ask a professional before power-washing old siding.
Demolition, additions or storm damage that breaks shingles.

Minnesota’s advice is to avoid breaking, sanding, cutting, drilling and sawing the material. North Carolina says the same: do not cut, sand, saw or abrade it.

Options owners usually consider

State agencies describe a few paths. North Carolina lists leaving it in place and keeping it painted, enclosing it with aluminum or vinyl siding, or hiring an asbestos professional to remove it. Minnesota notes that damaged material should be repaired carefully and can sometimes be covered with new materials, subject to local building codes, and it strongly recommends a licensed asbestos contractor for removal.

State rules differ. Connecticut, for example, publishes its own homeowner fact sheet with requirements that do not match Minnesota’s. Before deciding, contact your state environmental or health agency and ask what applies to a house like yours.

This guide does not give instructions for sampling, repairing or removing asbestos siding. Those are jobs for accredited or licensed asbestos professionals working under your state’s rules. See our Disclaimer.

Questions to ask

The home inspector

Is the siding or roofing a cement-type shingle, and does it look original?
Are any shingles cracked, broken, missing or chalky?
Is there an older layer of siding under the current one?
Should I bring in an accredited asbestos inspector before buying, given my plans?

The seller

What is the siding made of, and when was it installed?
Has it ever been tested for asbestos? Is there a lab report?
Has any of it been removed, covered or repaired, and who did the work?

Your insurance company

How would you handle a claim if a storm damages siding that contains asbestos?
Are there exclusions or limits for pollutants or hazardous materials?
Does the age or material of the siding affect my premium or eligibility?

Your contractor

Will your work cut, drill or nail through the existing siding?
Who will evaluate the siding before work starts, and are they accredited for asbestos in this state?

What to do if you have it

Leave intact siding alone and keep it in good condition.
Do not cut, drill, sand or break it while you sort out a plan.
Get it tested by an accredited professional before any project that would disturb it.
Use separate firms to test and to do any work. EPA recommends this to avoid a conflict of interest.
Check state and local rules before any repair, covering or removal project.

Common misunderstandings

“It’s asbestos, so it has to come off.” Agencies say intact siding is generally not a hazard. Removal is a choice, not an automatic requirement.
“Painting it is the same as sanding it.” Painting intact siding is different from sanding or scraping it. Ask a professional about preparation before repainting old siding.
“New fiber cement and old asbestos siding are the same thing.” They can look alike but are different materials. Test when in doubt.
“Vinyl over the top made the problem go away.” The old layer is still there, and future work can still disturb it.

Quick answers

Is asbestos siding dangerous to live with?

Not when it is intact and left alone, according to the state agencies cited here. The risk comes from breaking or cutting it.

Can I tell by looking?

You can recognize cement-type shingles, but only a lab test tells you whether they contain asbestos.

Does it need to be disclosed when I sell?

Disclosure rules are set by states and vary. Ask your real estate agent or attorney what applies where you live.

Before-you-buy checklist

Identify what the siding and roofing are made of and whether they look original.
Ask the seller for any test results or records of past siding work.
If you plan additions, new windows or re-siding, get an accredited asbestos inspection before closing.
Ask your insurer how storm damage to asbestos siding would be handled.
Check the era’s other materials with the House Age Decoder.

Asbestos Cement Siding: How to Recognize It and What to Do