I just had my roof done. It had 2 layers of asphalt and the original cedar roof.
The ribs on the rafters were 1"x2", spaced around 6 inches apart. I believe it was originally roofed in 1928 or so.
I found that the roofers DID NOT remove the ribs, and left many in place, broken, or semi-removes. They put down 1/2" ply on top of the ribs.
When I was younger I ripped many roofs, many cedar roofs were under asphalt, and we ALWAY took it to the rafters before any ply was put down.
I have never seen anyone leave the old & broken ribs in place, is this normal?
Also, wouldn’t the 1" stand off of the py to the rafter be a concern? ( I am also wondering what they used to attach the ply to the ribs / rafters, hopefully not roofing nails!)
Sounds like extremely poor work to me. Probably voids the manufacturer’s warranty. Sheathing needs to be fastened directly to rafters. I wouldn’t pay them until they made it right.
Very common to have it done this way in SoCal. There’s no “requirement” that the skip-sheathing be removed.
Here we have many that lay 1/4 inch ply with tar paper then install shingles over top. It never looks good but does not matter as long as the shingles shed water.
I only see it on steep pitch roofs so there is no chance of someone walking on them.
There is a big draw back and that is the nails have a tendency to creep out of the sheathing easily since the shank goes into the cedar shingles or shakes in some areas and not the skip sheathing.
I agree with Jeff it’s quite common here in southern Cal, I see it done all the time. I personally believe for the most part its stronger, more solid surface area to attach.
I agree with Jeff also. In Northern Maine, that was done many times, but we use 5/“8 plywood up there, but the skip sheathing to remain is usually repaired and others left intact. Re-nailed if possible.
When you stop and think about it. Sheathing on the rafters is supported every 24” o.c. and on the 6" skip sheathing it is supported every 6" and the plywood gets nailed at 6" or 12" oc.
So like I said the only problem is with the looks and creep out of nails on the shingles themselves not the sheathing.
So I also agree with Marcel.