If you re going to add a roof on top of an old one it s a good idea to remove any loose shingles and apply a new layer of 30 pound roofing felt before laying the new shingles.
New roof on old roof.
If your existing roof is fairly old there s a good chance the shingles are damaged.
When old shingles are torn off new roofing paper starter shingles ridge vent and moisture barrier are installed.
Shingle edges are curled or shingle tabs are cupped.
That s also why building codes commonly limit re roofing to no more than two layers.
The one we re putting on the old farmhouse is pennsylvania blue black and it s meant to last at least a hundred years.
Cost of a new roof.
Your roof is at least 20 years old.
Ranch homes for example are much easier to roof than tudor or victorian styles.
Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option.
Find a pre screened local roofing contractor.
Replacing an asphalt roof with new shingles will cost between 5 400 and 9 000 or an average of 7 211 for a 2 000 square foot home not including old roof removal.
Bed the end of each shingle in a 2 in wide ribbon of roofing cement placed 4 in.
The complexity of the roof.
The roof of a typical two story 2 000 square foot house with a gable roof will consist of less than 1 500 square feet of roofing area or about fifteen squares.
Bald spots where granules are missing.
Up from the valley center.
The actual cost will vary depending on whether it is a composite asphalt shingle roof or a fiber cement concrete composite shingle installation.
Shingle the addition roof letting the new shingles fold through the valley center and onto the old roof deck by at least 1 ft.
Installing new roof shingles over old effectively doubles the weight of the roofing so you have to make sure your roof structure can handle the extra load.
7 potential signs that your roof may need to be replaced.
Your house will probably be worth less.
A slate roof is a humbling thing.
A properly installed layover roof can look and function as well.
Shingles that are raised or misshapen make it hard to lay a smooth flat layer of new shingles on top.
The more peaks valleys skylights and other obstacles the roof has the higher the installation cost will be.
A layer of old deteriorating shingles can make your new roof look bad.
While many shingles today are produced for durability many factors can accelerate the aging of shingles.