Is it OK to put a new roof over an old one?

While a repair job can often be more convenient and somewhat more cost-efficient, placing new shingles over old ones is never a good idea. Whether repairing one section of roof, or a replacing a whole one, it's always best to pull up the old shingles before putting down the new ones.

Can you build a roof over an existing roof?

Roofing over an existing roof is also called reroofing or an overlay. It is the process where roofers install a new roof over your existing one, i.e. add a new layer of shingles, which means that there is no tearing off of the old roof.

Can new shingles be placed over old ones?

Installing a new roof over shingles takes less time than tearing off the old roof. Looks just as good and lasts as long. As long as it's done right and under the right conditions, installing new shingles over old ones can last as long and look just as good as a complete re-roof.

How long does a roof overlay last?

An overlay is a viable option if the existing roofing materials have not already been overlaid. Home Reference.net notes that on average you can expect the overlay to last for fifteen or sixteen years.

Can you put a second layer of roofing?

Adding a second layer of shingles will make your roof hotter because heat gets trapped between the shingle layers. Increased temperatures can lead to premature aging of the shingles. Layering new shingles on top of old ones, which might be curved or damaged, can result in some visible imperfections on your roof.

Can You Install A New Roof Over Old Shingles?

How many layers are allowed on a roof?

House roofs should never exceed three layers of shingles. Adding additional layers without excavation can save homeowners up to $1,000 in labor. Therefore, layering has advantages. Building and city codes require roofers to limit shingle layers to two.

What is one of the drawbacks to adding a second layer of roofing over a first?

Adding a second layer could compromise the structure of your roof. Problems fixing leaks: A second layer of shingles only complicates the job when a roofer is trying to fix a leak. Often, there is a problem with the first layer of shingles that was not apparent before the second layer was added.

Is a roof overlay worth it?

In the long run, an overlay roof is likely to cost more than a complete tear-off and re-roof installation project. That said, an overlay roof will save you money upfront, and can be done more quickly if you're on a time crunch.

Is a roof overlay considered a new roof?

Tear-off roofs are when a roofing contractor removes, or “tears off,” your existing roof, then installs an entirely new one. Overlay roofs are when a roofing contractor keeps your existing roof as-is, then places new roofing materials on top of it.

Should you always tear off old shingles?

In most cases, more than two layers of roofing shingles does require a tear-off. Laying new shingles over old shingles is easily prone to leaks and reduces the life of the new shingles. This alone ought to be reason enough to do a tear-off; it's just a bad value not to.

Is it OK to have two layers of shingles?

In most states, you're only allowed to have 2 layers of shingles on a roof for fire safety reasons. However, you'll still see roofs that have 3 or 4 layers today. If you already have 2 or more layers, a contractor will recommend a full replacement.

How do you blend old shingles on new roof?

The easiest way to tie in the new shingles with the old is with a cut valley (see Four Ways to Shingle a Valley). After the addition roof is framed and sheathed, snap a line on the existing roof shingles 2 in. up from the valley center, and cut through the shingles and underlayment.

What is the difference between re roof and new roof?

Roof Recover: The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering. Roof Replacement: The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.

Can you redesign a roof?

Changing the pitch of a roof is only possible when a roof's internal and structural materials are also replaced. When a roof's ridges, walls and rafters are switched out, there is a chance to create a new architectural design that can change the pitch of the roof.

How much does it cost to add a layer of shingles?

On average, you can expect to pay a contractor $3 to $6 per square foot to install your roofing. Prices can be higher if you choose a unique or complex shingle. The contractor will have to dispose of shingles, which costs an extra $25 to $150.

Can you overlay a built up roof?

Flat / Low Slope Roof Overlay Replacement as an Option (Retro – Fit) There are many ways to handle your roof replacement. A lot of commercial and residential flat roof owners know that you can install a new roof over top of an old one. Many old built-up roofs are still out there, and most even have rocks on them.

Is it bad to overlay shingles?

A: In general, it is not good practice to overlay a traditional asphalt shingle roof versus a complete tear off and replacement for the very reason you stated: you can't examine the decking to determine if there is any damage that needs repaired.

What is one of the drawbacks to adding a second layer of roofing over a first quizlet?

ROOFING - Drawback (inconvenientes) to adding a second layer of roofing over a first: The dead load is increased; Nails may not be long enough to penetrate the roof sheathing; Old flashing may not be replaced; the roof sheathing cannot be properly inspected; Roofing materials may not dry properly.

How long will a 2nd layer of shingles last?

Shorter lifespan – As you might expect, new shingles laid over damaged shingles and rotting decking won't last as long as they could. To make matters worse, a roof with two layers of shingles holds in more heat, which speeds up deterioration. On average, an overlay lasts around 16 years.

Can you put roof shingles on top of old roof shingles?

The Basic Rules. Know this: placing old shingles over top of the new ones is only possible with asphalt shingles, which are also known as composition shingles. You cannot place a new layer over top of slate or wood, and you should definitely never mix materials like laying asphalt shingles over cedar shakes.

Can I put 3 layers of shingles on my roof?

No, you can't put three layers of asphalt shingles on a roof. In most states, you're only allowed to have two layers of asphalt shingles on a roof for fire safety reasons. But that doesn't mean you won't still see roofs with three or four layers today.

Can you install metal roof over shingles?

In almost every case, the answer is yes, you can lay down a new metal roof over an existing shingle roof. This is one of the many reasons metal roofs keep growing in popularity – their installation doesn't require completely tearing off the existing roof, which is a time-consuming and expensive job.

How many times can you reroof a roof?

As mentioned above, homeowners are legally limited to two layer of roof shingles. Therefore, if you already have two layers, you'll need a full tear-off. Additionally, if your roof is severely damaged, it likely won't be able to support the weight of a reroof and will need to be torn off.