How many layers of shingles can you have on 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.

How many times can you shingle over a roof?

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.

Is it OK to put 3 layers of shingles on a 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.

Can I put another layer of shingles on my roof?

A second layer of shingles will decrease the integrity of your new roof and lower its lifespan. That's because shingles aren't designed to have a second layer of shingles on top of them! Plus, all that extra moisture and heat being applied to the first layer of shingles will make that first layer age faster.

Can you put shingles over shingles?

You might be able to lay new shingles over existing shingles and avoid the cost of tear-off. If conditions are right, new shingles laid over old shingles can be just as attractive and durable as shingles laid on bare sheathing.

How Many Layers of Shingles Can I Have on a Roof? ▬ ROOFING QUICK TIPS

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.

Do you have to 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 roof over an existing roof?

Installing a new roof over an existing one can only be done if you have shingles because you can only put shingles over shingles. It is not possible to mix materials, nor to install a new layer over slate or wood tiles.

What is the problem with more than two layers of shingles?

Warranty issues: Most shingle warranties do not apply when shingles are layered over existing roofing, according to InterNACHI. Two layers of shingles trap more heat, which in turn damages the shingles and shortens the life span of the 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.

How long does a third roof layer last?

Vented properly and installed correctly, you should get around 80-85% of the life span out of an asphalt roof. That means you can expect to get about 20-22 years out of your 3-tab shingle roof and 25-28 years out of your dimensional shingles.

Can you put 2 layers of shingles on a double wide?

The process for installing shingles on mobile homes is exactly the same as site-built homes. However, on site-built homes, two or three layers of shingles are acceptable. On a mobile home, one layer is the limit. This means, if your shingles need replacing, that's exactly what you need to do – remove and replace them.

How much does a new layer of shingles cost?

Asphalt shingles, the most common roofing material, cost between $120 and $400 per square. You'll also pay for flashing, trim, vent covers and gutters. You can keep costs down by shingling over an existing roof, rather than replacing it.

What layers should a roof have?

Can a roof be too heavy for House?

Changing to a heavier roof-covering material can cause compression cracking in drywall because the added weight can cause additional settling in the home's structural framing. This condition can actually be dangerous if the roof framing is not adequate to support the additional weight.

How long does a shingle roof last?

Homeowners with wood shake roofs should expect them to last about 30 years, while fiber cement shingles last about 25 years and asphalt shingle/composition roofs last about 20 years, the NAHB found.

How many layers of roof underlayment do I need?

Two layers of underlayment are required for low-slope roofs. The first course is doubled. Above that, 36-inch wide strips are then applied to the roof in a shingle fashion, starting at the lower roof edge, and overlapping subsequent courses a minimum of 19 inches.

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.

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.

Can you put new plywood over old on a roof?

As long as the new plywood itself can span the distance and carry the roof, wind, seismic and snow loads for your region, adding new ply over old is just fine. The new plywood thickness should be at least equal to the exusting plywood thickness.

Is it cheaper to shingle over an existing roof?

It's more affordable.

Simply adding another layer of shingles doesn't require as much labor as it would take to remove them first. Therefore, labor costs are much lower for overlay roofs.

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.

How do you remove old shingles?

Strip the Roof, Start at the Peak Using Roofing Tear Off Tools. Start the tear-off at the section farthest from the trash container. Standing at the peak, use a garden fork or a specially notched roofing tear off shovel to tear away the ridge caps and the top courses of shingles.

How long does it take to reroof a house?

In general, the roof of an average residence (3,000 square feet or less) can be replaced in a day. In extreme cases, it could take three to five days. Depending on the weather, complexity, and accessibility of your home it could even take up to three weeks.