Generally felt underlay roof works by combining two or three layers of material together to make an impenetrable barrier that is then coated with a waterproof finishing material to further protect the felt.
Flat roof how many layers of felt.
A third layer of felt needs to be placed.
Roofing felt is one of the oldest available options and advances made in the past decade or so have begun to move more towards the torch on approach.
Paint a thin layer of adhesive over the first felt layer.
However in almost all areas it is not acceptable to install more than two layers of roofing on any commercial building.
On 4 12 or greater slopes the balance of the roof shall be one layer of 15 felt.
The key to weatherproofing your flat roof is adding a total of 3 layers.
It must be installed the full length of all valleys.
Align this layer with the bottom of the roof.
Overlay a second layer of felt 2 to 3 inches and fasten it through the overlay so it secures the top of the felt underneath.
These thick layers of roofing felt are installed by heating the back of the felt with a butane torch and then carefully applying it to the roof.
You will be placing the second layer of felt over this.
On roof slopes of 2 12 to 4 12 the remainder of the roof shall be two layers of 15 felt applied in shingle fashion or 1 layer of ice dam protection.
Felt roofing is a very common material used on flat roofs such as garages garden sheds and on extensions.
For many years it was acceptable to put even the third layer.
This will help the two layers adhere to each other.
Add the second layer.
A layer of roof felt is laid down and hot asphalt is mopped overtop repeat for two to four layers called plies repair involves reapplication of original materials and or roofing cement to fix cracks or leaks.
Installing the roofing felt does take care but can go very quickly.
These applications are ideal for flat roofs or protective surfaces under roof level decks.
There needs to be an overlap in the felt to help increase the water tight quality.
Why use a felt underlay roof.
Thus you will repeat the earlier steps.
On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing.
Before adding the second layer though spread a thin layer of adhesive on the first layer using your trowel.
You wan walk over the roof to remove any air bubbles that may form.
Some roofing felts are actually glued down.