If you are getting a new roof, while you may not necessarily need to have the plywood decking replaced, you should have it carefully inspected by a qualified roofing contractor. The inspection should take place when the old shingles have been removed.

When should roof plywood be replaced?

As plywood lasts about 30 to 40 years and we run the risk of delamination and required replacement in a few years. The other two have stated that as long as the plywood is good and stays dry, it can last forever.

Will roofers replace plywood?

But at one time, some local building departments didn't require anything thicker than ⅜-inch. This thin plywood is now considered inadequate, so a roofer will usually replace it when they find it. Make sure your roofer is using the proper materials and installing your roof according to code.

How long does roof plywood last?

There are a few averages you can expect, but they are dependent on these factors. Plywood siding, such as T-111 should give at least a 35 year life expectancy, if finished properly; but there are many cases of it lasting over 50 years. Roof sheathing should last 30 to 40 years or to put it another way, two roofs.

How much does it cost to replace plywood on a roof?

With that said, the average cost to replace roof decking on a 2,400 square foot home is between $1,050 and $1,575. It'll take roughly 75 sheets of plywood to complete the job, putting the average cost of sheathing at $14 to $21 per sheet.

How To Replace Roof Plywood

What is the average price to tear off and replace a roof?

Depending on the type of roof you're replacing, the size, and pitch, the national average to tear off and replace a roof range between $5207 – $12,969. Here's what you're going to need to know to calculate the cost.

How much does it cost to replace rotted wood on a roof?

Repairing rotted wood costs anywhere from $500 to $10,000 or more. Pricing all depends on the extent of the rot and how easy it is to access.

How do I know if my roof plywood is bad?

If the roofline is in any way wavy, then it means your sheathing is damaged and needs to be replaced. You can also check for sagging from the inside. Go into your attic with a flashlight, and look up. If any areas of the roof appear closer to you than others, your roof is sagging, and it is time to call a professional.

Can you roof over wet plywood?

A: It is never a good idea to install a roof over wet plywood or any type of roof sheathing. Trapped water will boil when the sun heats the roof and the shingles will then have small pits where the steam finally escapes.

Can you put new plywood over old?

The new plywood will have to be nailed to the rafters or roof trusses. ... But, with the old plywood left in place, it will be considerably more difficult to locate the rafters to ensure proper nail placement.

Do roofers replace rotted wood?

Once your professional roofers have fixed the underlying cause of the moisture, they will need to replace all the wood affected by the dry or wet rot. Here are the tools and materials they will use and a step-by-step guide on how they will complete the job.

Which plywood is best for roofing?

CDX is the grade of plywood most commonly used for roofing (CDX plywood means it is Construction Grade for exterior purposes).

How do I know if my roof deck needs replacing?

1. Visible holes in your roof.
2. Signs of mold or mildew in your attic.
3. Missing shingles.
4. Roof sagging that's visible from the exterior or interior.
5. Curling and/or buckling shingles.
6. Shingles that are wearing in a granular pattern.

Is half inch plywood good for roofing?

Most Common Thickness

For rafters spaced 20 or more inches apart, 1/2- or 5/8-inch plywood is recommended. The most common rafter spacing is 24 inches, and 5/8-inch plywood is recommended for that. It will support roof loads for most situations and is the standard for most roof applications.

What causes roof rot?

Moisture is the primary cause of dry rot on flat roofs. Whenever the attic is poorly insulated and ventilated, high humidity can occur, resulting in the roof's wooden components becoming exposed to excess moisture. Rot forms as wood-eating fungi devours the fibers, making the wood structure dry and crumbly.

What is the minimum thickness of roof sheathing?

Sheathing must be a minimum of 19/32-inch thick. Never affix roof sheathing with staples; 8d ring-shank nails need to be used instead. The normal thickness range for sheathing is 3/8 to 3/4 inch.

What happens if it rains during roof replacement?

Rain is bad during a roof installation because the water can damage the roof decking. A new roof should never be installed over a wrinkled barrier or wet wood because this is against building codes. Also, asphalt shingles may not adhere properly to slick surfaces, particularly if there's high humidity.

Can you roof over wet underlayment?

Could underlayment itself protect the roof when it's raining? Yes, for a couple of days at least. Underlayment is installed much like the shingles themselves. We overlap the edges to make sure every inch of the roof is covered.

Are rubber flat roofs better than felt?

Durable. Unlike felt, rubber roofing doesn't scuff or mark easily. It also is less likely to crack or warp in the sun, less likely to blister or rot; probably the reason why it's claimed to have such a long lifespan!

What's the best roof sheathing?

OSB is now the most-used sheathing and subflooring material for new roofs and roof replacements. OSB is currently selling for less than plywood by approximately $3 per sheet, meaning a savings of several hundred dollars per conventional home.

How much does roof sheathing cost?

Divide the total roof area by 32 to get the number of sheets you will need to cover the roof. A typical 4 foot by 8 foot sheet of plywood covers 32 square feet. If your roof area is 1,600 square feet, 1,600 divided by 32 will mean you need about 50 sheets to cover the roof.

How do I know if my roof is bad?

1. #1. You have several missing or loose shingles. ...
2. #2. Your shingles are curling, cracking, dry, or blistering. ...
3. #3. The roof is sagging. ...
4. #4. There are dark/dirty areas on your roof. ...
5. #5. You have granules in your gutters. ...
6. #6. You notice several exposed or loose nail heads. ...
7. #7. ...
8. #8.

Can I treat dry rot myself?

The best product to use to treat and kill Dry Rot in masonry is Boron powder dissolved in water. You can brush the Boron solution onto the affected masonry or spray it on depending on the size of the affected area and your preference.

Does home insurance cover dry rot?

Is dry rot covered by insurance? Dry rot is a general exclusion for most insurers. If the dry rot can be proven to be the fault of bad building work – like, for example, botched plumbing – you might be able to claim back some of the costs.

Is Rotted wood covered by insurance?

Wood rot is typically not covered by homeowners insurance unless it is caused by a covered in peril your policy. Homeowners insurance provides coverage against sudden and accidental water damage, so if a pipe bursts and causes wood rot to your floor or ceiling joists, your insurer will likely cover repairs.