Recently had some trim installed and some interior painting done at our house. The painter installed some casing around interior doors and painted the trim. I asked him if he was going to back-prime the casing and he said that he didn’t need to since the nails were holding the trim in place. I thought for sure that all good painters would prime back and front of casing before fastening to wall. Any thoughts?
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" I asked him if he was going to back-prime the casing and he said that he didn't need to since the nails were holding the trim in place."
your painter said that!?
that's about like a trim carpenter saying the caulk will hold it in place LOL
No, IMHO interior trim doen't need backpriming......
Backpriming is only needed in situations where there might be water intrusion from behind the board -- like might happen with exterior siding and trim.
No need for it inside. And your painter was pulling your leg, probably because he thought you were pulling his. The paint doesn't hold anything, and he knows that you know that.
Unless you're the lead dog, the view just never changes.
If I had an old door (exterior) where I wasn't sure about the amount of temperature change and cold air and moisture coming in, I would back prime the interior trim there, but not on interior trim on interior doors. One purpose of back priming is to insure that moisture absorption is the same on both sides (low).
Gentlemen,
Thank you for the replies. My fears are put to rest. We always recommend that our clients back prime all of their exterior trim but I wasn't sure what the standard practice was for interior trim.
I can see if the casing was around an exterior window or door and there wasn't enough urethane foam sealing the rough opening how mositure may effect the trim.
I have seen mitre joints pull apart but I think this is movement in another direction which is not mitigated by back priming trim.
I always remember the days of my childhood when we would paint one side of a piece of paper and watch the thing curl because it was painted on one side.
Merci.
Miter joints should be end glued, not to hold, but so that the moisture doesnt go up the grain. That helps keep them together, but in dry winter, they are going to move no matter what.
-zen