As opposed to old built up felt roofing with joins new single ply waterproof membranes are now most commonly used.
Flat roof felt thickness.
Of course how many rolls you need will depend on the size of the roof so ensure you measure correctly.
There are two types of flat roof.
As the single ply roofing association spra points out this type of flat roofing is strong durable completely sealed and usually lasts at least 25 30 years.
The flat roof is torch on bitumen with torch on flashing this roof has been patched repaired previously torch on felt roofs have an approximate life span of 10 12 years merely as a covering.
Roofing felt s thickness is not a measurement of its depth because it is thin similar to heavy paper.
A built up roof bur sometimes called a tar and gravel roof is a tried and true style of flat roof.
Insulating a flat roof with recticel powerdeck u recticel s powerdeck u offers 0 024 u value for thicknesses 120mm or more so it s a great thermal insulator as well as a strong and stable board for structural integrity.
Cold roofs and warm roofs.
Roofing felt s thickness is actually measured in pounds per square with one square equaling 100 feet of roofing material.
Of course flat roofs are not flat but have a very slight roof pitch of between 1 4 to 1 2 per foot.
Just enough slope to drain water but also flat enough to be a problem if not constructed properly.
It s available in rolls that are 8m long and 1m wide with a thickness of 4 2mm mineral or 3 8mm sand.
Anderson tecnatorch sbs torch on mineral felt capsheet is used as the final layer of the felt roofing process.
Ikopro solvent free water proofer is an easy to use bitumen based emulsion for roofs.
The most commonly used felts are 15 and 30 with weights of 8 and 20 pounds per 100 square feet respectively.
However over the last few decades new and advanced materials have been developed.
Here alternating layers of roofing felt usually fiberglass and hot applied asphalt are combined to create a long lasting roof system.
We would recommend a different covering such as grp fibre glass.
A classic flat roof is either almost completely level or has a very slight pitch of 3 in 12 inches or less.