I am about to get a new roof done. I had a couple of estimates a year ago but then I put off doing it until now. The job is a complete tear-off and all new plywood decking. The present roof is old cedar shakes plus at least two asphalt shingle roofs on top of that. The rafters are all good, and the rafters have 1"x2" lathe strips nailed across them, and the old cedar shingles are on top of the lathe strips. The lathe strips are all in excellent shape.
On one of the old estimates there was a pre-printed line that said, "Install
8-ply (I think) plywood to all roof deck". The "8"(?) is crossed out and next to the line"All wood is 4-ply" was written in.I assume that 8-ply is better and more expensive that 4-ply, but my guess is that 4-ply is also normal and okay to use. Anyone know if that's correct?
Another pre-printed line said, "Install 15/30 pound felt paper to all roof deck." The "30" is crossed out and the "15" is circled. And, next to the line "and Iceshield" is written in. Again, I am guessing that 30 pound is better than 15 pound, but that 15 pound is also normal and okay to use. Anyone know if that is correct?
The rafters are on 24-inch centers. The person who did this estimate said they would take the existing roofs off down to the lathe strips, and then would nail the 1/2-inch plywood on top of the lathe strips. The lathe strips are fairly close together (maybe an inch apart) and he said that even though the rafters are on 24-inch centers, 1/2-inch plywood instead of
3/4-inch plywood would be fine because the lathe strips add additional strength.The estimate also specifies and includes a new ridge vent, new seamless gutters and downspouts, etc.
Another roofer who had looked at the job last year said that he would take the roof off down to the rafters and would use 3/4-inch plywood decking.