Should You Reroof Over Your Old Shingles?

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Shingle Me This: A Roof Blog Roofers have a tough job. They work at heights, carrying heavy shingles and nailing them to the roof's surface. In addition to working hard, roofers are also very knowledgeable. They can recommend the best roofing material to fit your budget and preferences, and they can make repairs, as needed, to ensure your roof continues to keep your home safe. There's a lot to learn about roofing. We are not professionals, but we consider ourselves to be well-informed, and we share the information we know on this website. As you read, you will learn more about roofing as a profession, and you may also pick up some roofing tips you can use on your own home.



A new roof can be a budget breaker, which is why it's good to have options available that may save you a bit of cash. One such option is reroofing. During a standard roof replacement, the contractors must tear off the old roof to the sheathing, and then they must replace the underlayment and the shingles. With a reroof, they leave the old shingles in place and simply install the new shingles over the top — effectively using the old roof as the underlayment. The following can help determine if your home is eligible for a reroof.

Has your roof been previously reroofed?

In general, a roof can only be reroofed once. If you already have two layers of roof on your home, both layers must be torn off and a fully new roof installed. There are a couple of reasons for this. With each additional layer of shingles, the chances for a major roof leak increases. Damage chances also go up, since the upper shingles won't be as well secured to the decking beneath the other layers of shingles. Further, damage that has developed in the sheathing may be missed since there likely hasn't been a full roof tear down in decades.

What material is your current roof?

Not all roofing materials can be reroofed over. Most reroofing is done over traditional asphalt shingles. These shingles lay flat and don't interfere with the new shingle layer. You can also reroof over certain membrane shingles. Slate or clay tile shingles, as well as gravel roofs, cannot be roofed over.

Is there any major damage to the current roof?

One of the drawbacks with a reroof compared to a full replacement is that damage may go unnoticed, which can lead to major leaks down the road. Every reroof should come with a thorough initial inspection. Some minor damage can be repaired, such as the patching of a small leak, and then the reroof can proceed as usual. Major damage, though, such as damage that results in damage to the sheathing, is better repaired with a full roof replacement.

What are the weight specifications for your roof?

Leaving the old roof in place and applying new shingles will increase the weight load on your home. Many area building codes require over-built roofs, so a little bit of extra weight is not a concern and you can proceed to reroof. Some older homes, though, may not have been constructed to current weight codes. You can check with the plans for your home on file in your local municipal office to find out the maximum weight load for your roof. Use this information to determine if a reroof is a good idea.

Contact a roofing service for more help about reroofing services.

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