Roof Poding Deflection Check

Hvac units without condensate drain lines could be the culprit.

Roof poding deflection check.

You can also perform preventative maintenance to ensure that the membrane stands the test of time. Structural design for ponding of rainwater on roof structures f. 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. The level roof surface is utilized for air handling units gas vents skylights and other mechanical equipment.

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. My tennessee home was started in may 2012 and the roof was put on in late june. Always inspect thoroughly before making a repair. Without sufficient stiffness deflection of the roof may cause successive ponding and deflection until the accumulated weight could conceivably cause failure.

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. If the beam is stiff enough then ponding can be minimized. An inspector will know how much ponding is acceptable on a flat roof. Pierce cautions that before roof repairs are hastily made the source of the ponding water should be investigated.

The aisc specification provides formulas by which the stiffness of a roof system may be checked. A flat roof serves as a superstructure from which to attach joists and suspend piping hvac ductwork and lighting systems from. A flat roof for commercial businesses make a lot of sense for a host of reasons. The shingles or sheathing on the homes roof is lifting deflecting causing ripples in the roof.

The builder was made aware of this issue and had the roofer who framed the house and installed. 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. Check drains to make sure they are free of dirt silt and debris. In roof systems that are essentially flat provisions must be made to support ponding water.

Asce 7 10 2015 ibc attributes ponding water to the deflection of relative flat roofs and identifies a susceptible bay for ponding as a roof slope less than 1 4 in 12. 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. 5 15 ponding on roofs. Ponding is a progressive event.