Add a new layer of shingles which means that there is no tearing off of the old roof.
Roofing over existing flat roof.
Flat roofs have three main options for their coatings.
Multiple layers of shingles can make it difficult or impossible for the nails to penetrate.
These new roofs can be either low sloped less than 2 12 functional roofs or high pitched greater than 2 12 architectural roofs depending on the expectations of the building owner.
Bur consists of many layers.
The condition of the existing roof is critical.
Built up roofing bur was the most common type of flat roof before modified bitumen and membrane roofing were developed.
It is an acceptable practice to install a new roof over an existing roof membrane system provided that the roof deck is structurally sound and has been properly prepared to support the added load.
The roof should be in sound.
If your current roof is in good condition or you re really short on time it might be your best option.
On the other hand a full replacement not only leaves you with a better looking higher quality roof it also protects the value of your home and could save you money in the long run.
A bottom layer or two of insulation board multiple intermediate layers of tar or asphalt alternated with layers of roofing felt and a top layer of gravel.
The fully adhered membrane wrapped down over the cut back roof deck to tie into the wall water control layer and air control layer photograph 11.
Roofing over an existing roof isn t necessarily the wrong choice.
One of the keys to over roofing is to tie the air control layer of the roof assembly to the air control layer of the wall assembly.
Silicone acrylic and aluminum coatings.
It is the process where roofers install a new roof over your existing one i e.
Roofing over an existing roof is also called reroofing or an overlay.
Coatings are great flat roof replacement options because they can be directly applied to the roofing surface.
How to install a roof over an existing roof determine the feasibility.
Inspect the condition of your current roof.
Mcelroy metal s retrofit roofing systems consist of adding sub structural components to the existing flat roof to build a slope into the structure and provide a platform to install new metal roofing panels.
These coatings are liquid applied directly onto the roof surface and then cure once in place.