The most commonly used felts are 15 and 30 with weights of 8 and 20 pounds per 100 square feet respectively.
Flat roof felt thickness.
The best weight for roofing felt is the 30 pound product because it provides thicker and stronger footing for roofers that does not tear out especially on steep roofs where footing is critical.
Of course how many rolls you need will depend on the size of the roof so ensure you measure correctly.
We would recommend a different covering such as grp fibre glass.
However over the last few decades new and advanced materials have been developed.
A classic flat roof is either almost completely level or has a very slight pitch of 3 in 12 inches or less.
Of course flat roofs are not flat but have a very slight roof pitch of between 1 4 to 1 2 per foot.
Roofing felt s thickness is actually measured in pounds per square with one square equaling 100 feet of roofing material.
There are two types of flat roof.
It s available in rolls that are 8m long and 1m wide with a thickness of 4 2mm mineral or 3 8mm sand.
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.
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.
Most flat roofs are typically not as long lasting or durable as sloped ones because the latter shed snow and rain a lot quicker.
Just enough slope to drain water but also flat enough to be a problem if not constructed properly.
The product can be used as a waterproofing coating on asphalt fibre cement sheeting concrete and bituminous roofing membranes.
A built up roof bur sometimes called a tar and gravel roof is a tried and true style of flat roof.
Ikopro solvent free water proofer is an easy to use bitumen based emulsion for roofs.
Roofing felt s thickness is not a measurement of its depth because it is thin similar to heavy paper.
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.