Wednesday, January 21, 2009

Metal Roof Repair: Why the leaky roof?

The first, and often the most difficult, step in metal roof repair is to diagnose the problem correctly. Possibilities include:

1. Corrosion

A metal roof is simply a steel deck with a coating on top (galvanized, Kynar, etc) to act as the roofing material. As the coating ages it develops the need for repairs. The chemistry of rust is actually quite complicated and the source can be galvanic, pitting, atmospheric, crevice, or a number of other types.

2. Poor workmanship (Improper design, construction, or maintenance)

Faulty skylights, HVAC units not flashed in correctly, gutters absent or improperly installed, leaky window casings are all more common sources of leaks than corrosion early in the roof’s life.

3. Severe Weather

High winds and heavy snow can overload a roof, causing damage that must be repaired immediately. An inspection should take place as soon as possible after a severe weather event.

4. Wear and Tear

Traffic on a roof, without a correctly designed and installed walkway, will prematurely wear most roofing materials. Coupled with corrosion this can also lead to structural failure.

5. Structural Failure, Building Movement

If the building owner waits too long to make repairs, the iron in the steel panels will start to corrode, leading to panel buckling. In time, the purlins and trusses that support the roof may also corrode. Buildings often settle with time and while this may not be a catastrophic event, coupled with normal material expansion and contraction this can lead to structural failure of the roof.