Roof Recover

So what is a roof recover?

To do a roof “recover”, also called a “lay over” or “overlay”, is to put a new layer of roofing over an old layer of roofing.  One of the few benefits of a roof recover is that you will not have to pay the dump fees, tear off labor or the cost of underlayment or labor for installation of underlayment/felt.  But the benefits really end there. Tearing off the old roof and starting new is what we recommend in most cases because the benefits far outweigh any potential negatives (cost). With a new roof from scratch you will never have to worry about having your new layer of roofing removed because the old roof curled up under the new.  We have learned from experience that is what can happen which is the main reason we advise against a recover.  Recovers also add more weight to the framing of the roof.

We will do a roof recover in certain cases however so here is some more info about them.

Building codes currently allow up to three layers of roofing to be applied to your home. The best type of roof for a roof recover are three tab shingle roofs because they lay flat and are less likely to cause bumps in the new roofing.  They can be over layered with architectural style shingles and in many cases as a result look every bit as attractive as if you had paid to tear off the roof.  Only a roofer or building inspector peaking underneath your shingles will be able to tell in many cases.  A recover over one layer of three tab can result in a long lasting leak free roofing system. The roof decking under your roof must also be solid.  Always get an expert opinion or two and make sure that building up a second or third layer of roofing will not cause the water run off to shoot over the top of the gutter system in a heavy rain.

Tear-Offs

Does my roof need to be torn off?

In most cases we will recommend a tear-off and new roof from scratch instead of doing a roof overlay.  In rare cases where a new roof is installed over your existing roof (a recover) always make sure they properly ventilate your attic. In almost all cases, continuous soffit and ridge vents will provide maximum cross ventilation and that is important to prevent condensation, mold and moisture problems in your attic.

If any of the following are true a complete tear-off of the existing roof system(s) should be considered:

  • Too many layers – If a roof has more than one layer of roofing, the roof should be torn off. In most cases this is a code requirement. Codes rarely permit more than two layers of roofing. To determine this, all you need to do is contact your local building inspections department.
  • Bad decking – If spongy areas are noticed when walking on a roof, or if you see sags between the rafters or trusses, there’s a chance that some of the roof deck may be deteriorating or be damaged. Deterioration can be attributed to dry rot or de-lamination of the plies in the plywood due to glue failure. Dry rot is wood rot caused by certain types of fungi and if it isn’t taken care of, it can spread. If there is suspicion of bad decking, then a full tear off should seriously be considered.
  • Ice dams – Ice dams can be a big problem. In areas where there the average January temperature can be below 30° F, and no ice and water protection membrane is present on a roof, then a full tear off should be considered. Twenty year old buildings with no ice and water protection and no prior problems, can suddenly experience thousands of dollars in damage when a freak cold front hits.
  • Incompatible shingles – If a heavy weight architectural style shingle is used to cover a light weight strip shingle such as 3-tabs, then the roof will look good. However, if a light weight shingle is used to cover a heavy weight shingle, the light weight shingles have a tendency to show all the bumps and ridges (called telegraphing) and won’t look good.
  • Existing roof is in poor condition -If the existing roof is in really poor shape, such as tabs being severely curled or if the rows are crooked, then a complete tear off and replacement should be strongly considered.

Tear-offs usually result in a longer life span – There is no known documented research, but most roofing professionals agree that with an overlay, the average lifespan of the shingles will be shortened by about 10%-20%. Another reason we recommend a tear-off and new roof from scratch.

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