[kmc]

I will cut the vent channel with a circular saw and either a plywood blade or a carbide blade. I intend to set the height of cut to the thickness of the plywood. Should I care if it slices the rafters during this process? Is there a safeguard to this?

 

[sixeightten]

Set the height on the saw and make the cut. Obviously, you don't want to cut any deeper than necessary. If you leave a small kerf in a rafter, it is no big deal.

 

[kmc]

thanks for that quick answer.

 

[sixeightten]

You might want to use an old blade. Many times there will be nails that you don't see.

 

[kmc]

You might want to use an old blade. Many times there will be nails that you don't see.

That's one reason why I might use the carbide blade. New saw. Maybe I'll just pick the cheapest one for this.