I am putting on a new roof and when I removed the old shingles, there are cedar shakes under them. When I took those off, there are spaces between the horizontal boards of the roof (it's not plywood). The roofer put the felt on over them. Don't I need to do something about all the spaces? The house is a wooden-sided two story built in 1906.

Yes, you need to put down, (my suggestion) is plywood, and then felt, then shingles.

yes, you need to go ahead and put down, (my suggestion) is plywood, and then felt, then shingles.

Is it possible to do what this roofer is doing and just felting over the whole thing and then shingle? Is there a down side to that? I live in snow country and thought that would be a lot of heat loss. Would I just put the plywood over the existing boards?

No problem putting plywood over roof slates. Most times 1/2'' ply is used. I like 3/4''. Gives more stability to the roof deck.

If shingles are installed over the slates, they will droop in the open space. This will be unsightly and could cause problem with leaking.

You will not be able to walk on roof for fear of stepping in area between slates. This will cause 2 problems. One is hole in roofing and the second you could get seriously hurt.

Chuck

Thank you so much.