Roof Poding Deflection Check

The shingles or sheathing on the homes roof is lifting deflecting causing ripples in the roof.

Roof poding deflection check.

In roof systems that are essentially flat provisions must be made to support ponding water. This was noticed for the first time a couple of months after the singles were installed. The level roof surface is utilized for air handling units gas vents skylights and other mechanical equipment. 5 15 ponding on roofs.

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

Hvac units without condensate drain lines could be the culprit. An inspector will know how much ponding is acceptable on a flat roof. If the beam is stiff enough then ponding can be minimized. 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.

Pierce cautions that before roof repairs are hastily made the source of the ponding water should be investigated. The builder was made aware of this issue and had the roofer who framed the house and installed. We moved into the house march 2013. Check drains to make sure they are free of dirt silt and debris.

Structural design for ponding of rainwater on roof structures f. 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. 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. Structural failure due to long term effects of ponding water.

A flat roof for commercial businesses make a lot of sense for a host of reasons. Ponding is a progressive event. 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. You can also perform preventative maintenance to ensure that the membrane stands the test of time.