roofing

It depends on whether you're talking contemporary or a number of years ago. It was originally wood, in some cases two layers of wood set in opposite directions, but I think the majority of newer houses use plywood. Puma

Not plywood, OSB (oriented strand board).

Plywood is used much less nowadays, but it would be fine to use it in a story.

It depends on many variables, local codes, the size of the crew, the height of the roof etc. Large sheets like 4x8 foot plywood or OSB can be very dangerous to handle particularly if you are higher up and have a smaller crew. In those cases, the contractor might go with roofing planks (Typically around here 1 inch by 10 inch (nominal) by 8 feet pine planks)

It varies a lot by location. South Florida has very different requirements for underlayment (the layers of stuff between shingle and wood sheathing,) method of attachment, type of nails, etc. etc. due to wind storm requirements. My house was built in 1973 and has 5/8" plywood sheathing. The houses across the street (same builder, same models, built a year earlier) have tongue & groove planks.

(I know this because of Hurricane Andrew... everyone down here became a roof expert, since there were pieces of them laying everywhere. BTW, plywood held up just as well as the T&G.)

What sort of shingles? If your roof is shingled with cedar shakes, the underlay isn't solid plywood but 4 inch wide wood lathes running cross wise with a 1 inch spacing between the lathes. The spacing is needed so the cedar doesn't stay wet and rot.

Most of the houses in our area were built about 25 years ago and many of them are replacing the cedar with tar composite shingles. The roofers pull off the cedar, nail plywood or composite sheets over the lath work and nail on the new shingles. They always use 4 ft by 8 foot sheets.

We haven't had to do yet that since our shingles were cut from old growth cedar so the wood was a thousand years old before the cedar trees were felled.

My house was built in 1949-50 and the roof is sheathed in tongue & groove boards. In the 1950's plywood became popular because of the housing boom. In 1964 Georgia-Pacific built a giant Plywood factory in Arkansas, and that's when the product really took off in the US, prior to that, most of it came from Canada.

The Lonely One said:

Hmmm alright what about a home in modern Pennsylvania? (Everett area)

Click to expand...

I have worked on several buildings in Pennsylvania in the past and found OSB to be the norm. 7/16" thick with a layer of 15 or 30lb felt paper and finally covered with fiberglass shingles.

OSB is the material of choice today, unless the customer requests plywood, or plywood is offerred as an upgrade. Historically, you can be safe to say you found plywood if the building is between 10 and 50 years old. Older, the roof would have been tongue & groove boards, newer, probably OSB.

OSB or plywood is fine. If you're using it in writing, i'd go with plywood. Most readers won't know what OSB is.