Roofing Over Existing Shingles

Why installing new shingles over old shingles can be good.

Roofing over existing shingles.

Roof over shingle over has its place there are always factors to take into consideration before starting a project. When roofing over your existing shingles can be a good idea. Leak around a dormer which the homeowner never knew about long term effects of shingling over shingles. Some roofers install a layer of waterproof shingle underlayment wsu over the existing shingles at the eave end as would be done for a roof laid on bare sheathing.

If the job is done correctly with the new layer of shingles laid flat over the existing shingles the old roof cushions the new one and serves as a secondary barrier should wind or water ever break through the new shingles. In a shingle over if some of the decking has buckled and warped over the years it likely isn t going to be noticed and fixed. Many arizona homeowners with shingle roofs do decide to roof over their existing shingles because. Let s start with the good.

When you should tear off your roof and start from scratch instead. Here is a video on how we lay a second layer of asphalt shingles over existing asphalt shingles. It is the process where roofers install a new roof over your existing one i e. However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life.

Re roofers have tricks to lay new roof shingles over old so that the same step ups between courses are maintained but if any old shingles are cupped curled or otherwise misshapen those defects will telegraph through to the new layer. Roofing over an existing roof is also called reroofing or an overlay. All shingle manufacturers honor the warranty whether their products are used for a reroof or a new roof. Plus the hours of labor go down and less equipment is used which lowers the cost even more.

Roofing over existing shingles on a roof with a 4 12 pitch can easily cost 1 000 less than tearing off and replacing an entire roof. This can lead to increased rot mold and decrease the structural integrity of your home. This provides added protection against ice dams. Add a new layer of shingles which means that the old roof will not be removed teared off.

The starter course or strip is rip cut so it butts up against the third courseof the existing shingles. Its front edge is even with the front edge of the drip edge. Hope you like it.