It would probably be
possible to do that, but it would be very time consuming and not likely to
result in an attractive installation. There are several things to consider if
you are thinking of trying to make this work.
A standard installation of flat surfaced cedar sidewall shingles would have
about a 5” exposure and the shingles would be 16” tall. That means that there
would be nails driven through the shingles at about 5-1/2” and 11-1/2” above
the bottom edge. You would need to carefully pull these nails without doing
much damage to the surrounding shingle. That may be possible on some of them,
but you would most likely crack or completely split many of them. When you look
at the back side of the shingles you remove, you will see many of them were
“blown out”. By that, I mean some of the wood around the point where the nail
came through was pushed out. This will further complicate putting them back up
and having them look good.
Another problem that you will have is the result of the shingles drying out
over the years. When shingles are new, they still have enough moisture in them
to be somewhat pliable. After they have been up on a house for one or more
years, they will be very dry and will tend to split and break very easily. This
will be a problem for removal and reinstallation.
If the shingles were painted or stained on the house, some of this will show on
the edges when they are reinstalled. You would need to paint them again after
putting them back up. If they are unfinished, they will probably be slightly
warped (from having dried more on the exposed surface than on the back) and
this will further complicate the reinstallation.
Finally, you would need to add some new shingles to replace the ones that were
damaged beyond reuse as well as those that will have to be cut to fit around
windows and under roof lines, etc. The mixture of old and new will be quite
apparent and will make the house look kind of patched together.
If you want to reuse old shingles, they would best be used as an under-course.
An under-course is a layer of shingles that is installed under each course of
shingles that will show. The course on top is generally installed slightly
lower than the under-course to provide a shadow line and give more depth to the
appearance of each course.