Minimum Thickness Of Flat Roof

However over the last few decades new and advanced materials have been developed.

Minimum thickness of flat roof.

Although there are certainly many times and places throughout the history of architecture where flat roofs have been used the flat roof has been intrinsically tied with modern architecture since it emerged from the modernist style in the 1920s. A classic flat roof is either almost completely level or has a very slight pitch of 3 in 12 inches or less. The idea is to provide positive drainage toward roof drains so there is no ponding water 48 hours after a rain storm. A flat polyiso underlayment board often referred to as flat fill is used beneath continuing repeating tapered panels.

Sheathing should be a minimum of 19 32 inch thick. Thickness or rating 1 the thickness or rating of roof sheathing on a flat roof used as a walking deck shall conform to either table 9 23 14 5 a. Most flat roofs are typically not as long lasting or durable as sloped ones because the latter shed snow and rain a lot quicker. 8d ring shank nails should be used instead.

Flat roof drainage up until the early 1920s was still essentially to the outside the perimeter which required a minimal fall in one direction. Out of interest you mentioned furring pieces for slope. Others would treat even steeper pitches as flat roofs. Never attach roof sheathing with staples.

2 the thickness or rating of roof sheathing on a roof not used as a walking deck shall conform to either table 9 23 15 7 a. Influential architects working in the early 1900s such as walter gropius and le corbusier saw ornamentation and traditional styles of architecture as. Tony thanks for that very useful. The definition of a flat roof according to bs 6229 is having a pitch less than 10 o to the horizontal however some in the industry would consider up to 15 o as their definition of a flat roof.

The typical thickness range for sheathing is 3 8 to 3 4 inch. Minimum nominal thickness mm for application. As my flat roof will be enclosed by a parepet with the drainage point being in one corner i knew i would need to build in the drainage slope towards this and thought i would do this using the joists themseleves but furring pieces make much more sense. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads.

The minimum slope for a flat roof is 1 4 per foot or 1 4 12 but some owners or insurance companies require a minimum slope of 1 2 per foot.