I wouldn't replace the sheathing unless it is damaged or rotted, and then I
would only replace the bad bits. You might want to consider some sort of
vapor barrier if there isn't already one there (tyvek is good) between the
sheathing and siding.

the nails shouldn't be a problem because they should not penetrate beyond
the sheathing....

--JD


"joe" wrote in message
oups.com...
I will be having my house re-sided with either cedar lap siding or
cedar shingles (currently it has cedar shakes that are poorly installed
(not sufficient overlap.) I have several questions.

#1--the sheathing underneath is shiplap (looks like 1x8 boards). Is
this significantly less strong than plywood sheathing? Would it be
worth my effort to have a layer of plywood installed over the top of
this shiplap sheathing? Also, this shiplap sheathing is installed
horizontally...I've heard its supposed to be diagonal...is this a bad
thing?


#2 When the siding people are installing the siding (and possibly
plywood), how on earth can they avoid the posibility of piercing a wire
or plumbing fixture?