Residential Flat Roof Detail

Traditional homes often have sections of flat roof over shed dormers above porches and garages and on balconies.

Residential flat roof detail.

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. Roofs tend to be either pitched or flat and typically in residential construction timber is the most common material used. Cad details document name pdf dwg download all cad construction details 37 1 mb 3 4 mb mc01 identification of roof areas 694 kb 167 kb mc01a single layer underlayment 678 kb 302 kb mc01b double layer underlayment 711 kb 322 kb mc02 vent pipe flashing 626 kb 349 kb mc03 valley. From there the flat roof system you choose will determine the materials you apply.

Of course flat roofs are not flat but have a very slight roof pitch of between 1 4 to 1 2 per foot. It must provide adequate protection against the elements keeping the buildings structure and interior dry. Underneath the basics flat roofs are usually constructed with a ceiling nailed to joists which support a deck usually wood in residential construction a vapor barrier insulation and a roof board. Most often used in commercial and industrial applications this flat roof system contains layers of waterproof membrane such as a treated fiberglass basemat tar and gravel to seal the flat roof surface.

A classic flat roof is either almost completely level or has a very slight pitch of 3 in 12 inches or less. Most flat roofs are typically not as long lasting or durable as sloped ones because the latter shed snow and rain a lot quicker. In the warm flat roof construction there is insulation packed into every possible space where air can flow. But flat roofs take a pounding from harsh weather which is why they rarely last as long as a good sloped roof.

And their horizontal lines abound in the west and in urban areas. The major difference between the warm flat roof and the cold flat roof has to do with the air flow between the roofing timbers known as joists that help to hold up the roof. Just enough slope to drain water but also flat enough to be a problem if not constructed properly. Introduction to flat roof details the roof is a key element of the building structure providing protection from the elements and has a vital role in reducing heat loss from the building.

A roof is defined in bs 6229 as a flat roof if it has a pitch of 10 degrees or less. A flat roof must be strong durable and stable throughout its lifetime.