Roof Poding Deflection Check

The aisc specification provides formulas by which the stiffness of a roof system may be checked.

Roof poding deflection check.

Without sufficient stiffness deflection of the roof may cause successive ponding and deflection until the accumulated weight could conceivably cause failure. In roof systems that are essentially flat provisions must be made to support ponding water. A flat roof serves as a superstructure from which to attach joists and suspend piping hvac ductwork and lighting systems from. The builder was made aware of this issue and had the roofer who framed the house and installed.

Asce 7 10 further clarifies roof surfaces with a slope of at least 1 4 inch per foot 1 19º towards points of free drainage need not be considered a susceptible bay. If the beam is stiff enough then ponding can be minimized. Always inspect thoroughly before making a repair. Fijneman eindhoven university of technology the netherlands faculty of architecture building and planning department for structural design and construction technology sdct ponding of rainwater is a special load case that can lead to roof collapse.

Pierce cautions that before roof repairs are hastily made the source of the ponding water should be investigated. My tennessee home was started in may 2012 and the roof was put on in late june. Structural design for ponding of rainwater on roof structures f. The more water on the roof the more deflection you get which means that even more water can be retained which leads to more deflection etc.

We moved into the house march 2013. The level roof surface is utilized for air handling units gas vents skylights and other mechanical equipment. An inspector will know how much ponding is acceptable on a flat roof. When there is the possibility of water ponding which may cause excessive loads and additional progressive deflection each component of the roof system including decking purlins beams girders or other principal structural supports should be designed accordingly.

5 15 ponding on roofs. This was noticed for the first time a couple of months after the singles were installed. You can also perform preventative maintenance to ensure that the membrane stands the test of time. The shingles or sheathing on the homes roof is lifting deflecting causing ripples in the roof.

Check drains to make sure they are free of dirt silt and debris. A flat roof for commercial businesses make a lot of sense for a host of reasons. Structural failure due to long term effects of ponding water. Bring in a roofing contractor to perform an inspection once or twice a year to ensure that the membrane is holding up and not worn or damaged in areas.