Can New Shingles Be Installed Over Old Shingles?

A second layer of shingles can be installed over a roof that is in relatively good condition. However, covering damage is likely to result in more problems. Structural considerations may also prohibit the addition of a second layer of roofing materials. Here are several important factors that could determine whether re-roofing is the right option.

Current Roofing Condition
If the current roofing on a structure only has minor issues that can be repaired, re-roofing can be a cost-effective solution. Roofers should check the following components:

Shingle condition
Deck and underlayment feel
Surface flatness

A good candidate for re-roofing will not show signs of curling, dips, gaps or humps. If any portion of the current roofing feels soft or spongy, repairs will be necessary prior to applying a second layer of shingles. Installing new roofing over damaged materials or layering on different types of roofing materials can cause major problems.

Structural Strength
A square, or 100 square feet, of installed roofing materials weighs 350-450 pounds. Adding a second layer of shingles will double the weight. If a structure cannot safely support this amount of weight factoring in a margin of safety for winter weather, a tear-off and replacement may be necessary.

Plans To Sell
Property owners who are planning a sale within a few years may want to consult experts about re-roofing. Home inspectors often report roofs that have two layers, and many building codes limit the number of layers of roofing. The quality of the work may offset this consideration, but buyers will anticipate a two-layer tear-off and replacement in the future.

Re-roofing with another layer of shingles can significantly reduce the labor cost of roof replacement. A tear-off may be necessary if major damage is present that cannot be repaired prior to being covered. Determine the best approach to roofing any structure by consulting licensed professionals in Edmond, OK.

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