In a fine homebuilding article describing techniques for installing Fiber Cement Clapboards, the author said he used 1.5″ thick rough sawn hemlock for the exterior trim. It was said that the texture matched the grain of the clapboards nicely.
Has anyone used this type of stock for exterior trim?
If I did use it, I would treat it with BIN and primer all four sides of it before installation.
Another question: I can get rough sawn hemlock from a local sawmill that has not been kiln dried. The factory recommendations for the installation of the Fiber Cement Clapboards says to leave a 1/8″ gap at butt joints and where it terminates into the trim.
Can the trim be treated with bin and primer before it is fully dry?
Can the clapboards be installed tight against the trim so that when the boards shrink the required space is left which can later be caulked and painted???
Thanks!
Replies
I am skeptical of hemlock for trim, but in any case, you want KD especially if you are going to paint.
What we call hemlock out here would be questionable for exterior trim. It's not a very stable material and not very rot resistant. I have seen problems with it moving when used for painted interior trim.
I bought a major load of roughsawn cedar 1x and 2x for siding and exterior trim from a local sawmill. I put it on stickers in an open shed and about 6 weeks later it's at 12-14% MC. The KD framing material used for the building has stabilized at the same level. You would need to dry your material awhile before priming.