Second Roof Layer

For many years it was acceptable to put even the third layer.

Second roof layer.

That in itself eats away at the savings. Steep sloped roof products such as tile slate metal and shakes only allow one layer. Use 1 5 or 1 75 inch roofing nails. The standard practice was that you could install a new layer of singles directly over the old layer during a re roof.

Install the second layer. Doing a second layer right means a lot of prep work goes into the overlay anyway and flashing which remember is the most vulnerable point on your roof is harder to guarantee. How to shingle over existing shingles and how to shingle a roof how to install roof shingles shingle layout lines h. Often there is a problem with the first layer of shingles that was not apparent before the second layer was added.

Add a layer of shingles over the newly repaired area before you install your second layer of shingles. The second layer is also more difficult to install properly compared to new shingles. Roofing second layer of shingles roofing. Plus depending upon the size of your roof you ve added multiple tons of weight which could pose a big problem if there is significant snow accumulation.

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. Flashing around roof penetrations and sidewalls can be compromised. That helps your final layer of shingles look flat with a proper installation. Another issue is that when you add in the second layer it can add extra weight to your roof.

However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life. In fact the extra layer can reduce your roof s lifespan by up to 40. This provides added protection against ice dams. Any more than that and you d have to tear off the old shingles before installing a new layer.

This step is important because it brings the underlying surface back to a level height consistent with the rest of the roof plane. The second layer of shingles will trap heat which can result in the decomposition of both roof layers. Adding a second layer could compromise the structure of your roof. The savings you re going to see may be in the range of a modest 25.

Asphalt shingles typically can have one more layer added over the top two roofs total. That second layer of shingles won t last as long. A second layer of shingles only complicates the job when a roofer is trying to fix a leak. On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing.