If your home has old-style asbestos-containing slate tiles currently installed on its roof, then you will be pleased to learn that with some special treatment you can install new slate shingle metal roofing right over the top of it. While you may want to remove the asbestos material because of health concerns, the safer thing to do is actually to encapsulate the asbestos under your new roofing materials. To do so in a safe manner, follow each of these time-tested tips:
Tip: Ensure that the Existing Roof is Stable Enough for Encapsulation
In order to be able to install your new slate shingle metal roofing panels over the top of your existing asbestos-containing roof, first, you must verify that the old shingles are stable enough to take the new roof. The best way to do this is to drill some screws into the existing roof and see if the asbestos-containing tiles crack or break apart. If the tiles crack or fall apart, then you will need to have them professionally removed and disposed of in a safe manner.
Tip: Use a Self-Tapping, Self-Drilling Type of Stainless Steel Screws to Attach the Slate Shingle Metal Roofing Panels
When attaching slate shingle metal roofing panels over your existing roof, you need to use self-tapping, self-drilling stainless steel screws. This type of screw is impervious to rusting and the self-drilling and self-tapping aspects help the screws go through the existing roofing tiles in an easier manner. This will reduce cracking and other damage to the existing roof.
Tip: Install Underlayment with the Slate Shingle Metal Roofing Panels to Lessen the Number of Screws Necessary
You need to install sheets of foam underlayment under the new slate shingle metal roofing panels. If you were attaching the underlayment foam directly on the plywood sheeting of your home's roof, then you would install it first before the roofing panels. However, to reduce the number of screws required to attach the new roofing panels, you should install both the foam underlayment and the new roofing panels at the same time.
Tip: Encapsulate the Eaves and Gables Using Specialized Flashing Material
Finally, once you have the new roofing materials attached, then you need to install a special metal flashing material around all of the eaves and gables. This metal flashing wraps around the ends of the old roofing tiles and ensures that any loose asbestos fibers will be encapsulated.