rough cut decking

[Bill Pace]

I am building a small house between Havillah and Chesaw, WA. I have a portable sawmill and an ample supply of Douglas fir. I have started a deck using rough cut 1 x 6 (true), that I have already air dried for several months. I have been trying to maintain a 1/4 " gap, screwing them to 2x8 deck joists on 16" centers. Even though these boards look pretty straight, it is hard to maintain an even 1/4" gap. I was wondering about building the deck with freshly cut 1x6, screwing them on the day they are cut with no gap and allowing them to shrink in place. I've been told that lumber doesn't get shorter as it dries, just skinnier. If that is true, this just might work. Anybody out there have experience with this method?

I plan to do most of the flooring in the house with a similar method once I get the kinks worked out.

Bill

[glenn kangiser]

Hi Bill - to the forum.  You are right up there by Mark -(Willy) who is out fighting fire now I think.

Yes - I have a sawmill and used a lot of wet wood.  My types of wood were pines - various and white fir.  Still softwoods and I expect about the same or less shrink with Doug fir.  I find about 5/8 inch shrinkage per foot of width on wet wood or about 5/16 on 6" boards.  Some that I had that was part way dry has about 3/16 to 1/4 gaps on 8" boards.  I think you could do what you want that way. 

Note that it is possible for shrinkage to shear screws so I like to use screw nails or ring shank nails in a nail gun - they will give a bit and bend as shrinkage occurs.  Screws are high carbon so like to break first.  Plain steel nails will dark streak the wood if exposed to water.  Galvanized nails don't streak.  Senco makes good ring shanks that are electro galvanized - not heavy galv but pretty good.

[miss_coast_cabin]

Bill, another possibility, since you've got a good supply of logs, is to quarter-saw. The boards are more stable than just sawing a cant and edging - so called straight sawn. Quarterd boards have a 45 degree or steeper end grain. The method gives a little less yield from a log. See R. Bruce Hoadley's Understanding Wood for some illustrations and explanation of whi it works.
Don't forget, even after air drying to equilibrium moisture content, a deck sees the extremes of dry and wet conditions, and, worse yet, differently on top and bottom.
BTW, our straight sawn deck of utility grade 2x6 untreated held up for years on the Gulf Coast. It got wet, but was out of the sun.