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Applying stucco over asbestos shingle...

Richard_Dutro's picture

Anyone have any experience or suggestions on using stucco over top of existing siding that is asbestos?

(post #171378, reply #5 of 10)

Thanks for your input. Here's the whole picture. House built in 1928, pine siding on the framing covered by asbestos shingles. Removing the two requires a bunch of labor (not to mention the disposal of the shingles) I've tried a test area with lath attached to the exterior with sheetrock screws. Used a bonding agent, and applied stucco over the lath. Semed to adhere rather well to the asbestos shingles. Encapsulating the asbestos, although not friable, is not a bad idea with my neighbors houses located about 20 feet to either side. Asbestos has gotten a somewhat bad rep among the smoking society, but is still a great fire barrier(but really ugly as siding). I was looking for historical data on expansion problems and the resultant "shedding" of the stucco layer. Full disclosure of the asbestos to future owners would be required of course. In this application, it might actually be an asset. Again thanks for your reply.

(post #171378, reply #9 of 10)

Anyone have any experience or suggestions on using stucco over top of existing siding that is asbestos?

(post #171378, reply #1 of 10)

Hi Richard,

The best and only advice is to remove the asbestos and then reside.

Having asbestos hidden under stucco will lower the value of the investment. Current laws, in many jurisdictions, demand that new buyers be informed of any hazardous materials inside the house or building.

In installing any stucco system, the sub-layer is very important to the quality of the installation.


(post #171378, reply #2 of 10)

Abating the asbestos could be more costly then the decline in value from disclosing its presence. Check with your local codes: asbestos is something you do NOT want to mess with: it should be done by a licensed abatement company.

(post #171378, reply #3 of 10)

It is my understanding the the form of asbestos in these siding shingles is a non-friable (sp) type. I believe this means that when they are broken, there isn't the airborn particles flying around. I have probably torn off asbestos siding on about 50 - 60 houses over the years and have never been questioned by any building inspector, debris removal company, or anyone else who might have concerns, except for a few homeowners. A few of them have been curious about the asbestos thing, but they end up being happy that it's no big deal.

As to putting stucco over asbestos, or any other type of siding, Gabe's last sentence says it all.

FWIW Red dog

(post #171378, reply #4 of 10)

Richard, Here in Oregon transite shingles (cement/asbestos) can typically be removed by non-liscensed people even on commercial buildings. Contractors have to get a permit and abate the materials according to guidlines. Believe it or not this is one area where the government can actually help you by providing information on the correct procedures. Try your Departmant of Enviroment or perhaps OSHA.

It would not be permitted to stucco over transite if mechanical fastners were driven through the shingles. Basically you can't cut it, break it, drill it, etc. because this is what releases the asbestos. Removal is one shingle at a time by nipping the heads off the nails or pulling the nails in a way that does not break the shingles. Shingles are then carefully repacked into poly lined boxes for disposal. Disposal will vary per area.

joe d

(post #171378, reply #6 of 10)

My first three years as a carpenter I spent a great deal of time 'installing' asbestos insulation. I crawled about in crawl spaces and attic spaces barely big enough to fit through, and manuevered a hose, to blow the insulation where it was needed.

I never wore a mask. I breathed, (deeply), the fibers of asbestos over and over again. Due to sinus problems, I am a 'mouth breather', so I certainly inhaled a good deal of unfiltered asbestos.

I have never had a problem with asbestos fibers in my lungs.

I do not dispute the potential for harm, but I have a problem with the way that asbestos is treated as imminent death by people today.

I have also removed miles of cement/asbestos board from the exteriors of houses, using none of the precautions everyone reccomends. Still no problem...

Caveat : the following is my opinion alone, and not that of Taunton or any other entity... Not only that, but I freely admit this could possibly be the stupidest advice I have ever given. LOL

Just wear a good respirator and gloves, break the crap off the house, stuff it in doubled garbage bags, put those in a cardboard box, and dispose of it properly. Then do your stucco. Although I suspect that after the asbestos siding problem is gone you may be more prone to use some other siding solution.

(post #171378, reply #7 of 10)

Hello Rich,

I personally have not done this, but I have seen it done many times.....guys who attach wood furring strips to the house siding and then vinyl siding overtop of this. They first install the fanfold insulation over the asbestos shingle using roofing nails. Then they attach the wood furring on top of the fanfold by drilling holes through the furring and shingles and using long screws to attach to the subframing. Once these strips are in place, they install the vinyl in a normal fashion. The furring is installed vertically.

No one in my area has ever questioned this, though I'm not really sure this would be approved.

As far as the stucco being only as good as its substrate, as long as the metal lath is attached firmly to your house, the stucco will adhere just fine. The metal lath is really what holds and bonds the stucco. Wood framed houses are stuccoed all the time with the use of metal lath. Tar paper is first installed onto the plywood walls, and then the metal lath is installed to the plywood. The stucco doesn't bond to the wood, nor does it have to. It bonds to the lath. If the lath is secured with a non-corrosive fastener, your OK.

I don't know if any of this would or would not be approved "officially" in your area, but yes it should work just fine.

Perhaps you should consult with your local building inspector.


(post #171378, reply #8 of 10)


NONE of that would be approved "officicially."

A good laugh,


(post #171378, reply #10 of 10)

Try going to they use grail coat as an approved encapsulation product for asbestos. This is probably the least invasive approach... for what it's worth