New Decking

After tearing off the existing shingles, I found that the boards are in bad shape. Can I just nail new osb over the existing boards instead of tearing off the old deck?

We will somtimes will take 3/8" CDX plywood and go over the old sheathing. OSB is crap.


cut out the rotted 1x decking and replace with 1 " plywood. dont waste time and money on recovering
your deckin.


Yeah, remove the cancer and replace with new CDX. I wouldn’t go over bad wood. Besides, if the wood is bad what are you nailing to?

I agree with you guys that you don’t want to cover wet or rotting wood.However a plywood overlay like I previously mentioned
is ideal on jobs where there are lots of gabs,knot holes and spaces on the old decking.of course the plywood layer should be nailed to the rafters. Its cost effective,quick and makes a good solid deck. We have to do this sometimes on houses built in the 16 or 1700s.


Always good to cut and and replace any bad wood when covering up with new wood.

Another method is to remove all the boards and gap to spec and add boards. Usually when I tear off a roof I like to get it covered as soon as possible. The time it would take to move around the decking has to be longer than going over it. It would also cost a lot more to buy the 1 by’s than to just go over with osb.

as long as the existing wood is not wet then 7/16 osb is more than adequate to any building code as long as you hit the rafters with your fasteners

Thanks for the replies. The existing wood is just falling apart. It’s not wet or rotted. I’m going over it with 1/2" osb and nailing it to the rafters.


that will work fine