Roof Poding Deflection Check

We moved into the house march 2013.

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. The shingles or sheathing on the homes roof is lifting deflecting causing ripples in the roof. 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. If the beam is stiff enough then ponding can be minimized.

In roof systems that are essentially flat provisions must be made to support ponding water. My tennessee home was started in may 2012 and the roof was put on in late june. You can also perform preventative maintenance to ensure that the membrane stands the test of time. Check drains to make sure they are free of dirt silt and debris.

An inspector will know how much ponding is acceptable on a flat roof. Structural failure due to long term effects of ponding water. Ponding is a progressive event. 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. 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. 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. This was noticed for the first time a couple of months after the singles were installed.

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. 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. Hvac units without condensate drain lines could be the culprit.

Structural design for ponding of rainwater on roof structures f. Pierce cautions that before roof repairs are hastily made the source of the ponding water should be investigated. The level roof surface is utilized for air handling units gas vents skylights and other mechanical equipment. The aisc specification provides formulas by which the stiffness of a roof system may be checked.