Loads will vary with the pitch of the roof.
Roof change plywood.
A half inch cdx plywood is often used with rafter with 24 inch spacing.
Rotted plywood cannot support the weight of a roof the way healthy wood can nor can it safely grip the nails put into the roof and keep them held firm.
Step 6 unroll new roofing felt over the new plywood and extend it at least 3 inches over each edge of the new plywood.
This is a popular option because it presents homeowners with functional but affordable roof sheathing.
That will suffice on a roof with rafters set 16 inches apart with minimal roof loads.
If your roof carries a heavier load like if there s less pitch and or it snows in your area a roofer may recommend the use of the inch variety.
Most roofs will be sheathed in plywood at least 3 8 inch thick.
Inspect the underlying roof sheathing for damage and make any needed repairs.
Install a layer of roofing insulation as recommended by the roofing manufacturer.
Place a new plywood board in the same location ensuring the ends align over roof rafters.
Secure the plywood by inserting six penny nails along the rafters spacing them every 6 inches.
Hammer down any large nails that are exposed by the removal.