HVAC Roof Leaks

Most roofs have some sort of roof mounted HVAC equipment, frequently mounted on curbs. Roof mounted HVAC units contribute to leaks if not properly maintained. The two most common problems with HVAC units are improperly piped condensate drains and outright leakage of the units. Improper handling of the condensate can also shorten the life of the roof.

HVAC units typically have a “wet” side and a “dry” side. The wet side is exposed to the sky and readily allows rain water to enter. It is designed to conduct this water out of the unit without leaking into the building. The dry side, on the other hand, is not designed to be wet and if water does enter it can and will get down into the building. Wet sides, however, sometimes do leak into the building and dry sides often get wet (especially when their access doors are not properly secured and come loose.)

When there are repeatedly roof leaks in the vicinity of an HVAC, it’s time to think it’s likely not the roof. RAMCON technicians are trained to differentiate between roof leaks and HVAC leaks and will assist you in identification.

Most curb mounted HVAC units dump their condensation through a pipe on the side of the unit. These outlets require a “P-trap” to be installed to ensure proper operation of the drain. Without a trap it is possible that the condensate drain will not function and the condensate pan will overflow into the building below causing what appears to be a “roof leak”. Often this drain problem is not constant, so the unit drains properly sometimes and sometimes it does not. This makes it difficult to isolate the source of the problem and identify the true source of the perceived “roof leak”.

Once condensate gets out of the unit it is either dumped directly onto the roof or conducted away in piping. At RAMCON, we strongly recommend that it be piped to the roof drainage areas, as we consistently see roof deterioration from the corrosive fluids of the HVAC units. This is especially true of built-up roofing systems, as the consistent presence of these corrosive fluids on the granulated cap sheets and aluminized smooth surfaced roofs accelerates the deterioration of the protective surface and significantly shortens the life of the roof.

See the photograph above. The “staining” shown by the arrow is actually a thinning of the granules because the roof has been continuously wet over prolonged periods of time. The water coming out of the P-trap should be piped all the way to the drain. This roof now needs restorative repairs which would otherwise not be required had the condensate been handled properly. With gravel surfaced roofs condensate handling is less of a problem, however, the gravel tends to hold the condensate and become a breeding ground for plant growth which can harm the roof. These conditions are a major factor here in Florida, where AC units run almost continuously.

RAMCON can assist you in installing these condensation lines and making sure they are secured to the roof properly.