We have begun the project of repainting our home. Purchased two years ago, a bank repo. It has cedar shingle siding that has been painted at least twice before.
We have the house about 1/2 done with a pressure washer. The old paint remains on the shingles we just cleaned. Is this OK or do they have to be bare for new paint to adhere better? We got a little crazy with the pressure washer on the first side we started, its almost bare and mild damage to shingles I’m sure. How long do we have to wait to start with a primer? How can we tell when it is dry enough to paint? Is the point of pressure washing to clean the house or to remove all/part of the old paint?
The cedar shingles don't have to be bare. The purpose of washing is to remove dirt, dust, pollution and maybe some loose paint. As you found out, trying to strip the paint with the pressure washer is dangerous.
The shingles will dry out after a couple of days. The only definite way to tell if they are dry and to what point is to use a moisture meter. Just wait a couple of days. If the singles feel wet or are rewetted wait a little longer.
As you are waiting for the singles to dry, you can start looking for loose paint and caulking. Remove the loose material before priming.