Can You Attach A Roof To An Existing Roof?

A roof is an important part of keeping the water out. Hiring a quality roofer is important to make sure you don’t have any leaks down the road. Sometimes attaching a roof to an exciting roof is a reasonable option.

Honestly, you may be looking at your roof and wonder if you can lay down new roof shingles over the old?

Fortunately, the answer is yes. It’s a common practice to add new roof shingles over old ones. Yet, now that we know, we need to consider a few of the reasons why you might want to do this. Then we will review a lot more reasons why this may not be a good idea. However, before we jump in, one thing should be made clear: adding new roofing over old (sometimes this is referred to as a “re-roof”) is possible only with asphalt shingles (also known as “composition shingles”). You can on re-roof with wood or slate, for example, and you should not mix materials. For example, don’t lay asphalt shingles over cedar. Plus, your current roof must be in reasonable condition. Otherwise, it may lead to expensive repairs down the road. 

Why re-roof?

It might seem like an obvious benefit by having multiple layers of shingles on your roof. However, it doesn’t automatically make your roof more waterproof. It can actually cause its own set of issues. So then, why would you want to add new roof shingles over your old shingles? The answer is straightforward:  convenience and cost. If you keep the old shingles on, you skip the loud, messy, labor-intense removal step, known as the tearoff, and you’ll save a bit of money on the roof job.

As mentioned the benefits of re-roofing have its caveats. It’s clearly easier and cheaper to just to leave your old shingles, however, there’s some special preparation involved with a re-roof job (namely removing vents, ridge caps, and misshapen shingles, among other things) and you still have to replace or add new flashing, which is often tricky over old roofing. Eliminating the tearoff could save $1,000+ on a new roof, but in truth you are only kicking the cost can down the road. When it’s time to replace your roof again, you will have no choice but to start fresh because two layers is the maximum allowed in most places. That means you’ll have to pay extra for the two-layer tear-off and disposal.

Why Not Add New Roof Shingles Over Old?

As we noted above, the potential cons of re-roofing can outweigh the potential pros, but it is all dependent on your specific situation. The reasons not reroof, and also some factors or things to check out if you’re really considering adding new roof shingles over old ones, Shingles can add weight on your roof, reroofing can impact new shingle warranties, if something happens under the shingles, it’s harder to get to the issue location.

Talk with roofing specialist to determine the best course of action.