Sunday, October 23, 2011

Beams

This will be the first of three posts about the wood framing that has been going on for over a week now. As expected, this work is a lot faster than concrete and masonry. The place looks very different already. First the 4 x 12 beams were cut to length, notched, and bolted to the steel columns. (MAN it's easy to say that.)





These beams are the primary horizontal structural component for this part of the house. They will hold up the roof, in other words. But also because of the four-bolt connection to each steel column, no walls are necessary for lateral stability. Interior walls are just for privacy, and exterior walls are just for keeping out the weather. So if someone (or group) ever wanted to use this house for something requiring no interior walls, all could be removed. But mostly I think I just like the clarity and honesty of this system: what holds everything up and together is obvious. Contrast this with typical stud wall construction, where load-bearing walls are indistinguishable from non-load-bearing walls, and even in the load-bearing walls it's hard to be sure which studs are doing the work. That's always seemed a bit sloppy to me, a copout for more careful construction.

The exact size of these beams is 3 1/2" x 11 1/4" - much thicker than anything typically used. Which means they were a "special order" and took three weeks to get, despite being our homegrown "southern yellow pine." That was one delay that I in my general contracting ignorance didn't expect.

The beams and columns will all be visible in the final house, so I wanted to be sure the connections were clean and consistent. In an early meeting with the framer I pointed to the detail of this connection where I called for a 1 1/2" space between the end of the beams and the face of the steel columns - everywhere. And he did it.



And behold, below, the prettiest beam in the house. The framers thought to place it in my laundry room. I thought about having them move it, but something about this resonated with the gospel. The prettiest wood in a service area... the best will be the least... the greatest will be your servant... the Prince of Heaven coming to Earth. So I left it.


I also noticed that some of the beams had black stains on them. In the photo below you can see it on the beam in the upper right corner.


Someone suggested it was "blue mold" and could be washed off with a bleach solution. So I tried scrubbing the stain with bleach, but it didn't budge. Then I saw this piece of scrap cut from one of the beams.


The stain penetrates deep into the wood. After looking this up online I learned that it is caused by a fungus; the stain is not fungus but is left by the fungus, so it can't be removed. I called the lumber supplier to ask why "number 1 grade" pine would be allowed to have black stains. I didn't get much of an answer. Lumber grades apparently refer only to how many knots are allowed. I'd rather have knots than black stains. I was told I should always expect to see some members with stains, especially in 4 x 12's, since only one of them can be cut out of an entire tree in most cases; too many trees would be wasted if every one with stains was trashed. I think - surely there's a better way. Perhaps don't buy from tree farms that are infested with fungus?

Fortunately I had enough extra that I could replace the beams that had the most stains - some were entirely black - with ones that actually looked like wood. The beam I pointed out in the upper right of the above photo was one of them.

So all the beams were finally set, then the steel columns were leveled, shimmed and tightened. Next up: exterior stud walls.

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