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Can you put new roof sheathing over old?
Although I don’t think installing new plywood roof sheathing over the old would be a grave mistake, I would not recommend doing it, for several reasons. The new plywood will have to be nailed to the rafters or roof trusses. The result could be a poorly attached roof surface, more vulnerable to wind damage.
When should you replace plywood on a roof?
How long does roof plywood last? Roof plywood should last twenty years, so long as it is not exposed to water.
Can you put new plywood over old plywood?
1 Answer. If the old plywood was clean and not infested with dry rot or mold it should be OK to cover it with the new plywood. One thing to consider is that the new plywood probably wants to be the same thickness as what would be used if it was used by itself on the rafters (i.e. if the old plywood had been removed).
Is sheathing the same as plywood?
Plywood sheathing (OSB or plywood) is often mistaken for plywood underlayment. They are not the same. Plywood sheathing is most often used to construct the structural sub-floor. OSB is constructed using long strips (strands) of wood that are held together with wax and adhesive.
Should I Resheet my roof?
Your New Roof The most efficient and cost effective option is to resheet directly over the shiplap with exterior grade plywood. This is acceptable by code, as well as the roofing manufacturers. And when you need a new roof, you need it to be installed correctly.
Is roof sheathing necessary?
Roof sheathing is important as it is a layer of wood and as mentioned above, it attaches to the trusses and joists on the roof. Then the shingles attach to the planks of wood. This keeps the water out of the home so it is a necessary part of the home.
How do you replace rotted sheathing?
How to Remove Siding and Repair Sheathing Step 1: Find Stud Edge. SCR_111_02.jpg. If a section of sheathing is rotted or otherwise damaged, cut out an area that spans from stud to stud. Step 2: Remove Damaged Section. SCR_111_03.jpg. Step 3: Attach Nailers. SCR_111_04.jpg. Step 4: Drive New Sheet. SCR_111_05.jpg.
How much does it cost to replace plywood on a roof?
The thicker the plywood your roofer uses, the more expensive the job will be. Your price could vary depending on how much the roofing company charges for labor, but generally, you can expect to spend between $70 to $100 for each sheet of plywood.
How do I know if my plywood is bad on my roof?
Bowing or bulging: Moisture and wood rot may cause your decking to sink in or swell up. From the outside, this looks like you have a bulging or bowing spot on your roof. The shingles above this spot may not function properly. Further, the decking can eventually fall in.
How long does roof sheathing last?
You can expect the wood roof sheathing of a home to last 100+ years. Although it should last for the life of the home, roof sheathing lifespan can be shortened by moisture penetrating it from both above and below.
Can you shingle over wet plywood?
Do not shingle over wet or damp roof sheathing or damp felt paper. The trapped moisture cannot evaporate when the sun heats the shingle. Use similar roof sheathing materials — i.e., plywood or three-quarter-inch lumber — to repair holes that might be discovered in the original sheathing when the shingles are removed.
What is the best sheathing for a roof?
OSB is now the most-used sheathing and subflooring material for new roofs and roof replacements.
How thick is the plywood on a roof?
Most roofs will be sheathed in plywood at least 3/8 inch thick. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads. Loads will vary with the pitch of the roof; the flatter the roof, the greater the load on any one section.
What does it mean to Resheet a roof?
When doing a roof replacement project, there’s a chance that your contractors will propose to remove the existing roofing material and re-sheet it with plywood. This step is known as roof re-sheeting.
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.
Is sheathing plywood exterior grade?
CDX is the most common exterior plywood grade. Oriented strand board (OSB) is an engineered plywood substitute that many builders use for sheathing and roof decking. It’s constructed with waterproof glue and performs best when only semi-exposed to the elements, as it is when covered with siding or roofing.
How thick should roof OSB be?
Standard roof sheathing thickness is ½” to ⅝” thick. If you are using OSB for your roof deck, then ⅝” is the recommended thickness. For plywood, which is slightly stronger than strand board, ½” thick is appropriate. Another factor is how far apart your trusses or rafters are spaced.
