Laying New Roof Over Asbestos

First the siding installation process itself nailing into the existing boards or tiles is enough to disturb the existing material and create a dangerous condition.

Laying new roof over asbestos.

Once again thickness can be a consideration as is the amount of maintenance that natural stone requires such as sealing and cleaning with stone cleaners. The first stage is to fix a framework to hold the metal sheets in place directly to the purlins underneath the asbestos cement roof sheets. If you are using an epoxy based thin set mortar and are willing to seal the tiles after installation natural stone tiles such as marble or granite can also be used over asbestos. Some people attempt to solve the problem of deteriorating asbestos siding by installing vinyl siding over top of it.

All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof. This is a cost effective approach with an aesthetically pleasing and watertight result. The problem with coating old asbestos sheets is that the surface is likely to be a bit soft and friable due to age and so the coating does not stick for a long time its generally a temporary repair for a couple of years or so it is possible to replace just your sheets and lap the new sheets to the adjacent roofs. My guess is that the asbestos is broken up enough at this point that if the metal panels are removed the asbestos will need to be removed as well.

This means the new roof cannot get enough stability on top of the old one a common risk of over cladding. However many asbestos roofs are built with concrete portals meaning the roof is supported by a small number of concrete arches. I do suggest a layer of underlayment over the asbestos so that when you fasten into the asbestos you do not create any airborne fibers. When overcladding an asbestos cement roof it will also be necessary in most cases to include a layer of insulation to meet current day building regulations.

However the ability to install over old asbestos roofing requires that several factors be met and it sounds like your roof has not done this. Asbestos over cladding in some cases asbestos containing materials need not be removed and can instead be over clad. This practice is not recommended for a number of reasons. Next most of the modular shingle shake tile style products can be installed over asbestos.

This is especially true when it comes to asbestos cement roof coverings. If the job is done correctly with the new layer of shingles laid flat over the existing shingles the old roof cushions the new one and serves as a secondary barrier should wind or water ever break through the new shingles.