Second Roof Layer

Use 1 5 or 1 75 inch roofing nails.

Second roof layer.

A second layer of shingles only complicates the job when a roofer is trying to fix a leak. Flashing around roof penetrations and sidewalls can be compromised. Add a layer of shingles over the newly repaired area before you install your second layer of shingles. This provides added protection against ice dams.

How to shingle over existing shingles and how to shingle a roof how to install roof shingles shingle layout lines h. 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. Place the top of each starter shingle firmly against the bottom of the shingle immediately above it and even with the eaves then nail it into place. On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing.

The second layer of shingles will trap heat which can result in the decomposition of both roof layers. 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 step is important because it brings the underlying surface back to a level height consistent with the rest of the roof plane.

That helps your final layer of shingles look flat with a proper installation. Roofing second layer of shingles roofing. The standard practice was that you could install a new layer of singles directly over the old layer during a re roof. Adding a second layer could compromise the structure of your roof.

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. 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. Another issue is that when you add in the second layer it can add extra weight to your roof. Install the second layer.

Asphalt shingles typically can have one more layer added over the top two roofs total. For many years it was acceptable to put even the third layer. That second layer of shingles won t last as long. Most people would limit this practice to a total of two layers of shingles.

Steep sloped roof products such as tile slate metal and shakes only allow one layer. The savings you re going to see may be in the range of a modest 25. That in itself eats away at the savings. The second layer is also more difficult to install properly compared to new shingles.