Layers of bitumen felt are heat welded onto each other to form an impenetrable barrier.
Flat roof felt layers.
Steep sloped roof products such as tile slate metal and shakes only allow one layer.
Built up roofs are installed using several layers of a special type of roofing felt that has been asphalt impregnated and embedded in bitumen applied with a hot mop.
For many years it was acceptable to put even the third layer.
The 3 layer felt roof system is also versatile when it comes to appearance.
In short any roof covering that can make a flat roof waterproof in one layer unlike roofing felt with its 3 layer system for instance.
On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing.
Plies are the layers of felts fabrics and mats that make up roofs.
1 built up torchon felt system.
Always stand on a firm section of the roof and wear long pants long sleeves and safety glasses.
Cover the edges of the roof with strips of felt before laying out the final layer.
Apply another layer of adhesive to the top for maximum waterproofing.
Laying the first nailed layer of underlay felt.
Remove the plies of the flat roof by thrusting into them with a spade.
Laying down felt on a flat roof is an easy and effective way to improve the strength and durability of an outdoor structure like a garage or shed.
If you are thinking about refelting a roof or replacing a layer of felt take care that you use the appropriate type of roof felt and adhesive.
This type of flat roofing felt has been in use for decades and is still used today.
This can include epdm rubber and fibreglass talked about above but commonly especially in the trade and in this article it refers to pvc tpo tpe and pib.
Each of the three layers is laid in a half lap system so any joint in the roof is as far away as possible from another joint.
You will follow the same process as in step 2 for the last layer.
Laying the top bonded layer of top sheet felt.
Laying the second bonded layer of underlay felt.
You can cover the surface of the felt with gravel for added strength.
Asphalt shingles typically can have one more layer added over the top two roofs total.
Fitted using a blowtorch the 3 layer felt roof system benefits from being more stable than the older methods.
Bituminous felt is a form of waterproof sheeting that is used to cover flat roofs or as an underlay beneath slate or tile roofing.
A third layer of felt needs to be placed.
This layer is not bonded to the decking so that the decking can move without damaging the felt roof.
The substance itself is made from bitumen which comes from the distillation of crude oil that has been either mixed with sand or crushed limestone.
Here is a video showing how the felt is installed on the flat roof.
Installing any gutter drips.
