I have a problem with a couple of replacement windowsills on the southern side of my house.
They replaced the windowsills when I had vinyl windows installed and the wood is not as stable as the old windowsills were. I am getting a couple of recurring checks that end up splitting the paint and allowing water into the check. Every fall I apply a couple coats of paint and in short order the paint cracks at the check and is susceptible to all the rain we get
here in the NW.
Does anyone have any ideas how to fix this problem, short of replacing the sill? I've tried exterior spackle to fill the check, that didn't work. Maybe flexible caulk? I think part of the problem is the check is not real wide or deep so I can't get much caulk into the check. Any suggestions would be appreciated.
I have been using oil based primer with good quality latex top coat. I think the wood is fir or hemlock