Reroofing Asphalt Shingles Roof

Most asphalt shingles should last without leaking for 15 to 20 years. Some last longer – even 25 or 30 years. After about 15 years, however, you might start checking for signs of wear. But don’t jump the gun. There is no advantage in re roofing a house ahead of time – before the shingles have started to deteriorate and years before they are ready to spring a leak.

Reroofing consists of applying new shingles over the existing roofing material. This is less expensive and easier than a tear-off job, which requires that the old roofing be stripped off and hauled away.

Tear-Off or Reroof?

The first step in determining whether or not to reroof is to check the rake of the roof to find out how many roofing layers there are. (The drip edge sometimes is applied before reroofing and may hide evidence of previous layers). Once you determine the number of layers, check local roofing codes for the maximum number of roofing layers allowed – the figure will be different depending on the type of roofing and pitch of the roof. For asphalt shingles, codes usually allow the original plus two layers of reroofing.

All rotten boards under the old roofing must be replaced, Go to the attic and examine any suspicious...