Flat Roof Construction Layers

The felts are reinforced with either glass fiber mats or organic mats ply sheets and when joined with the bitumen form a durable roofing membrane.

Flat roof construction layers.

It is a waterproofing layer made of regular felt stacked above the solid decking board and then completely covered by the shingles or other roofing materials. Flat roofs are hard to replace. Four plies denotes a four layer flat roof membrane system. 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.

For that reason cold flat roof construction needs to keep in mind the need for unblocked airflow. This only applies to flat roofs over habitable parts of your home so it excludes garages sheds some porches and most door canopies. Hot tar and gravel. Pvc roofs are especially strong and durable featuring a minimum breaking point of 300 pounds per inch.

The membrane roof is the latest roofing technology and is also the roof of choice in commercial construction. On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing. Since 2005 if you replace 25 or more of your roof covering felt then you need to ensure that the entire flat roof has enough insulation to satisfy current building regulations. For many years it was acceptable to put even the third layer.

Asphalt shingles typically can have one more layer added over the top two roofs total. This could mean flat roofs may not raise the same red flags they used to. Some observers suggest it s harder to replace a flat roof than a traditional pitched shingle roof because of the labor required to remove its layers especially on older flat roofs. There are several methods and materials for the design of the exterior surface of a warm or cold flat roof.

Roof covering typically of flat and rectangular shapes and made of various materials such as slate wood flagstone plastic metal and composite materials. The 3 most common materials used for flat roof construction. All three types of flat roofing cost 250 to 350 per square 100 square feet but prices vary according to region and size of the roof. The number of plies on a roof implies the number of layers i e.

Flat roofs usually come with a 10 to 20 year warranty but can last 25 years if you build the roofs right and maintain them using commonsense rules. Built up roof bur the traditional hot tar and gravel. But now flat roofs often are constructed with fewer layers because of improved waterproofing technology. 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.