One Layer Roof

However installing new flashings including special drip edge flashings made for reroofing will ensure a tight seal and a long life.

One layer roof.

That comes out to a total of an additional 7 350 lbs. 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. This provides added protection against ice dams. I have a 1949 1600 sf under roof with 8 12 pitches valleys and hips 2 6 rafters on 16 on center sheathed with 3 4 center matched lumber going over at least 1 layer of 3 tab shingles a partial tear took off the old tabs and left a nice wavy surface in pretty good shape.

And that is using a 30 year dimensional shingle. We explain when double coverage of felt underlayment is recommended and we describe how to figure out if your roofer installed a single layer or double coverage layer or maybe no layer of felt under the roof shingles. Yes if you have one layer on your roof your home will more than likely hold it and you will never know the difference. Most building codes allow this but is it a good idea.

On the flip side removing the original roof shingle layer drives up the replacement cost so the decision is an economic one. Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option a properly installed layover roof can look and function as well. Roofing felt underlayment layers. Chances are your roof structure was designed for a dead load of one layer of shingles plus extra for snow and a safety margin.

In other words an easy simple roof. First of all multiple layers of shingles simply means layering a new asphalt shingle roof on top of the old one rather than stripping the roof completely to expose the sheathing and replacing it with new shingles. As a result you ll typically lose one quarter to one third of the roof life. 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.

Having an old layer of roof shingles under your new layer accelerates that process as the original layer holds a lot of heat. That is for the standard walkable ranch or manufactured home. Here are the pros and cons. Pros to overlaying a shingle roof.

Double layer or double coverage roofing underlayment are defined here.