Slope Of Membrane Roof

Technically we are talking about low slope roofs that have a slope less than or equal to 3 12.

Slope of membrane roof.

This means for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit. Roof coating and membranes serve a vital purpose for buildings and enclosures with flat roofs. When it comes to low slope roof membranes there are differences you should be aware of. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.

Modified bitumen membrane roofs shall have a design slope of not less than one fourth unit vertical in 12 units horizontal 2 percent slope for drainage. Epdm roof membrane can be secured in a number of ways. Modified bitumen roof coverings shall comply with cgsb 37 gp 56m astm d6162 astm d6163 astm d6164. Formation of ponds on flat roofs is detrimental to the longevity and effectiveness of the roof.

Membranes and coatings are designed to create a strong seal to prevent leak when water begins to build. So the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally. Thermoplastic single ply membrane roofs must have a design roof slope of 1 4 12 or greater 2 slope. Some tpo membrane assemblies also have relatively low maximum roof slope limitations.

For example some epdm membrane assemblies have maximum roof slope limitations as low as 1 2 12. This system can be used for a large number of projects including home expansions cabins garages annexes carports sheds and workshops. When we say flat roof we don t mean perfectly flat which is undesirable since water still needs to be shed to roof drains. Minimum slope for a membrane roof.

If a roof increases in height by four inches for every foot of horizontal run it is considered to have a 4 in 12 pitch or just a 4 pitch talk in terms of pitches and you will always be understood in the roofing universe. Sprayed polyurethane foam roofing minimum roof slope roof pitch r905 14 1. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. Pvc membrane assemblies generally have higher maximum roof slope limitations.

These membranes are particularly effective for roofs with a very low slope between 1 8 12 1 and 4 12 33. As a building owner it can be helpful for you to understand the characteristics of the roof membranes on your building. For this type of roof shingles and other traditional coatings are less durable and less aesthetic. It is imperative that the right slope for the flat roof be adopted to avoid all these potential problems.