Until the 1940s exterior grade plywood was not available.
How to tell if plywood roof deck needs replacing.
The tear off gets a lot more complicated if you have something other than asphalt up there.
Other s ymptoms of a failing roof include high energy bills and ceiling stains.
The inspection should take place when the old shingles have been removed.
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.
Knots in the planks can cause it to break after the roof is done so if it looks iffy it is best to replace it.
These are the things an experienced roofer can tell you after the deck is cleared of all shingles.
Soaked or waterlogged decking can warp which can lead to a bowed or wavy roofline and ceiling.
Since the boards used for shiplap were manufactured here in the pacific northwest it was still cheaper than plywood up through the 1960s.
I replaced a roof last summer which had a deck made of 1x6 planks so you see there are various types of decks.
A sagging ceiling or roofline is another clue that there are major problems with a roof s decking and the roofing structure.
Missing shingles are caused by natural weathering high winds age and possible improper fastening.
Roof decks on homes built before 1970 are often 1 8 fir pre plywood shiplap.
If you think you might need a new roof the first place to check isn t your home exterior it s your attic.
Splits can form in the planks and they will get longer from the heat in the attic.
So arm yourself with a flashlight and climb up under the eaves.
That moisture can lead to rot and damage in the roof deck.
A failing roof deck will impact the integrity of a roof.
You walk on it you check the spacing between rafters you determine the thickness and if is it plywood or osb.
If you can see original wood shingles on the underside of your roof when you re up in the attic you ll need not only to tear everything off but also to install new plywood decking all of which likely adds 5 000 or more to your costs.