Flat Roof Sagging

Even the highest quality materials don t last forever though.

Flat roof sagging.

Foundation problems with the house. Less common causes of a sagging roof poor quality roofing material and faulty installation can cause a roof to slump. Excess weight along the roof can occur from snowfalls. Damage to the roof s surface permits an entryway for water and the subsequent weakening and sagging of the rooftop.

The most important step when fixing dips in a flat roof is to determine the cause of the problem. Sagging or low spots in a flat roof may be due to undersized or weakened roof joists or problems with the buildup layers beneath the exposed roofing. The roofing structure should be in good condition to allow adequate water runoff from the shingles. Water damage from rain and snow can lead to a sagging roof.

So what happens with those elements is that you get more sagging and delamination of the roof sheathing. When the roof framing is assembled two ceiling rafters are often joined together to create a longer span. Low quality materials are more prone to water and weather damage and generally deteriorate faster. Grab a flashlight and head up to your attic to inspect your roof rafters and decking specifically those where your roof is sagging.

Fixing a truss or rafter. Weakened sheathing rotting joists and sagging insulation are some possible causes. Also inspect the metal or plywood gusset plates used where your wood meets on a truss look for damage that includes cracks rot breaks and any other impairment. If structural damage or decomposition is to blame it may be best to tear out the section of roofing and repair the problem before filling the hole.

Most people without any construction experience know that a roof should be flat and not wavy or sagging. Why roofs sag as mentioned roofs sag because there s too much weight or load for the existing structure. A wavy or sagging roof can be the result of one of several issues. The other thing that causes this type of sag is an excessively long roof rafter without proper bracing and in old house that s not so unusual.