Residential Flat Roof Detail

Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof.

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. Having a manual for warm flat roof construction with details and a summary of rules to follow helps. Of course flat roofs are not flat but have a very slight roof pitch of between 1 4 to 1 2 per foot. Yet for historic modern style buildings like this old house s cambridge tv project flat roofs are at the core of the architecture meant to reflect the broad horizontal lines of the natural landscape.

The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls. Some observers suggest it s harder to replace a flat roof than a traditional pitched shingle roof because of the labor required to remove its layers especially on older flat roofs. Of course you don t need to live in a modern house to deal with a flat roof. A roof is considered to be flat when it is of a slope of 1 5 o to the horizontal.

Although flat roofs are cheaper to build than pitched roofs they have a shorter life span. A flat roof usually consists of the following. Most modern residential homes have relatively steep pitches. Pvc membranes are easy to maintain and repair.

Wind uplift is a primary concern when installing a retrofit single ply roof system rsprs over a structural metal panel roof. This could mean flat roofs may not raise the same red flags they used to. However in many u s. Cities with older housing stock think federal hill in baltimore or alexandria virginia s old town the roofs are often flat or have very low slopes.

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. A typical flat roof repair costs at least 350 400 and involves locating sources of leaks and patching the seams or holes. Flat roofs are hard to replace. Astm e 1592 physical testing was performed on three test roof assemblies in order to determine the wind uplift resistance of an rsprs installed over existing structural metal panel roof systems fastened directly into purlins.

However depending on the severity of the damage and the type of material installed repairing a flat roof can cost as much as 600 800. Flat roofs make replacing a roof a challenge. Waterproof membrane to prevent water penetrating the structure and interior of the. Just enough slope to drain water but also flat enough to be a problem if not constructed properly.

That will help you remember certain factors and details to build the best possible flat roof. But now flat roofs often are constructed with fewer layers because of improved waterproofing technology. Flat roof construction for residential. Flat roof systems are a bit of an outlier.