How to Cover Asbestos Siding on a Home Safely
Adding top layers won’t make asbestos go away, but it can make it slightly less dangerous
- Hammer
- Nail gun
- Utility knife
- Tape measure
- Saw for cutting the siding
- New siding
- Any required permits
- Waterproof sheeting
- Foam board
- Nails
Covering asbestos siding takes roughly half the time as removing the original siding, but it might not be the best idea. For the majority of homeowners, it is better—and safer—to pay a pro to remove and replace the asbestos siding. After you receive the all-clear, then put up new siding. There are some instances, however, when you may just want to add siding on top of old siding that contains asbestos.
Note: Before performing any of these steps, and throughout the entirety of this project, you will need to wear the proper safety equipment. This includes a mask and goggles at all times, as well as a disposable full suit, rubber boots, and disposable gloves.
Covering Asbestos Siding: How to Do It Safely
Safety is the most important consideration when covering asbestos siding. Taking the proper precautions and adequately preparing the area will help keep you safe. You’ll also want to inspect the siding thoroughly before beginning work.
Prep the Area
You cannot treat asbestos like a normal building material, so you must prepare the area beforehand. Other than removing all items close to the wall and making sure all your windows are shut and sealed, you will need to make sure there are no fans that would pull any disturbed asbestos fibers into the house or ventilation system. You usually would powerwash a wall before doing work, but in this case it is not advised.
Check the Existing Siding
Asbestos siding is usually quite brittle, especially if it has been exposed to harsh elements over time, which most siding has. You should go around the house making sure that no tiles are brittle or falling apart before starting this project. An easy way to check for brittle tiles is to tap them lightly with a screwdriver or hammer. If a large majority of the tiles crack and disintegrate, you may have to remove the asbestos siding entirely.
Install Foam Board
Photo: Lex20 / iStock / Getty Images Plus / Getty ImagesA foam board layer will be the first layer that goes on top of the existing siding. It is put in place mostly for insulation, but also to lessen the amount of noise you hear in the house. These foam boards come in large sheets and can be laid over existing siding as long as it is uniform. Foam board is generally installed with nails, and it is much faster and more precise to use a nail gun than hammer in nails by hand.
If the existing siding is in good shape but not uniform, you may want to consider adding a layer of furring strips at this stage, as well as after the moisture barrier. These strips simply make it easier to attach the foam board to the existing asbestos siding.
Add Moisture Barrier
Once your foam board is installed, you need to add a moisture barrier to protect the foam and the siding behind it. A moisture barrier also doubles as an asbestos barrier, helping to seal in any fibers that became airborne while installing the foam board or checking the siding.
Install Furring Strips
Furring strips are long, thin strips of wood used to create a flat surface on which to hang things like drywall, foam boards, or siding. They also exist to create a gap in between the moisture barrier and the outer protective layer. This allows for better insulation and moisture control. Installing furring strips between a foam board and existing siding is often optional (it may depend on local rules), but installing furring strips between the moisture barrier and the new siding is a requirement.
Install New Siding
Photo: Venerala / iStock / Getty Images Plus / Getty ImagesWhichever siding you choose is up to you, but probably the most common siding put on top of asbestos is vinyl. Vinyl is low-cost, easy to install, and resistant to the elements. It provides a decent seal that helps protect against asbestos leaking out, but it is never going to be as good as removing the asbestos entirely.
DIY vs. Hiring a Pro to Cover Asbestos Siding
The above steps sound straightforward, but this project takes many hours and you are dealing with a dangerous material. Hiring a pro is always going to be the right move when there are health risks involved. Expect to pay between $75 and $200 an hour to hire a local professional asbestos removal company.
Encapsulation, which means completely sealing in the asbestos with an adhesive, is an alternative to removal. This process uses a powerful sealant to bind asbestos fibers so they cannot be released into the air. This method is only suitable in some situations and must always be performed by a professional.
Frequently Asked Questions
Asbestos siding is harmful as it can produce fibers that, once inhaled into your respiratory system, may cause mesothelioma, other lung cancers, and a dangerous scarring of the lung tissue called asbestosis. You can contain the siding within a series of barriers, but it is our recommendation that you hire a professional to remove any asbestos in your house. Its presence can permanently alter your health and the value of your property by as much as 10% or more.
Asbestos has not been used to manufacture new siding since the early 1980s. So, while asbestos is not currently used to make new siding, it can still be present in the siding of homes built before the 1980s. The best way to know if your siding has any type of asbestos is to have a professional test it.
Scraping off asbestos siding is extremely dangerous. When asbestos is inert, it does not pose a risk, but once disturbed, the fibers enter the air that you breathe and can cause irreparable damage. Professionals may scrape it off, but they will have more protective equipment and specialized tools that most homeowners do not have on hand.
You are not really supposed to seal asbestos with paint, but in theory it could work—the caveat being that this is extremely dangerous and should be avoided at all costs. The only real way to seal asbestos is with the professional application of an encapsulating material like epoxy. Due to the negative effect asbestos can have on your home, however, it is usually the best course of action to accept a costly fix and remove the material entirely.
if you install new siding on top of old asbestos siding, you may keep the fibers trapped, but it would not necessarily be considered encapsulation. To do so properly requires a professional, who uses a certain type of sealant that needs to be spread over the asbestos in a number of layers in order to trap all the fibers. Although you may be able to buy this sealant yourself, it is highly advised that, once you find asbestos, you call a pro immediately.
