Power Beam Uneven Dimensions
Cottagebuilder
| Posted in General Questions on
I have an 11 7/8 x 3 1/2in Anthony Power Beam. I’m not sure if it got left in the weather at the lumber yard or what but it’s cupped. One side measures 12 1/8in and the other side is 11 7/8in. I need to use the beam around a stairway and need to attach subfloor to it for exterior walls to sit on, but with it being so uneven I’m not sure what to do. Will it shrink down to 11 7/8? Will the weight of the walls compress it? I thought about plaining it down but if the high side shrinks down eventually then it will be too low. Does anyone have experience with these beams and how much they can expand and contract?
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Replies
I only have a little direct experience with Anthony PowerBeams, but they are wood and all wood behaves the same way: it expands when wet and shrinks as it dries. Going from saturated to dry, a 12" board can shrink up to 1/2" so your 1/4" expansion is within a normal range.
If it weren't pressure treated you could use a moisture meter, but the copper treatment makes it hard to measure. (There are probably moisture meters that can measure the moisture content but I don't know of any.) In the factory they would monitor the weight to assess dryness.
In any case, it will eventually shrink, so if I were you, I would put it on sawhorses with the wide side up, facing the sun. Unless it's raining, in which case you would be better off putting it in a dry room, ideally with a dehumidifier. Or just install it and plan ahead for the eventual 1/4" shrinkage. There is also a chance that the whole beam has elevated moisture content, in which case it might shrink even more.
If you have enough length, you could carefully weight a slice off one end, then put it in an oven for a few hours at 200°F, then weight it again. The change in weight can be used to determine the current moisture content.