This question relates to material selection for an arbor/ pergola. The design calls for 2×6 in 16′ lengths and 4×4 posts. As an exterior project pressure treated lumber would be the obvious choice but untreated fir or pine would look a ton better and perhaps shrink and twist less. The design is open, air flow is not a problem and the material will be primed and painted. Any sugestions, pros or cons?
Thanks,
PAUL
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Replies
Untreated fir or pine will twist, split, and deteriorate, but that's good if that's the look you want. If not treated pine, why not consider the more durable outside woods like cedar, cypress, or the farmed Brazilian woods?
I'm having trouble finding the types of materials you sugested in 16' lengths. I even called azek and they couldn't help me out.
paul
Join shoter lengths, maybe. Sixteen feet is very unusual, and I'd guess that the cost of the joinery jigs/tools would be less than custom lumber. And you have the tools afterward.
Hi Paul,
You should be able to source douglas fir or red cedar in 18' lengths if you like. 2x8 Douglas fir is commonly used in residential framing for space conscious designs...
Most yards will stock 16' 2x6 Red Cedar or Redwood... Obviously not Homer Depot-they cater to only the big selling sizes. They don't even carry 12' posts...
If you are wanting this thing a solid colour use oil based solid stain by Benjamin Moore (no...they don't pay me to tell you that--yet).
Lumber that grows in tropical (wet) climates naturally develop ways to cope with all the moisture and insects--and thus last longer when taken from their environment into a dry climate.
Cracking is caused by unstalble grain-the core of the tree in a piece of lumber is a giveaway that this piece of lumber will twist and crack.
Fir trees rotate as they grow for even canopy exposure to sun-as they dry after milling they will shrink back (twist). Because of the circular grain in lumber-when you square a timber with the core in the piece, a crack will develop out from the core to the closest outer edge... normally on all 4 sides. The closer to the core-the larger the crack. Look at the edge of the timber while in the lift. Choose the Quartered pieces first for crack and twist free lumber.
Good Luck with it!
L
GardenStructure.com~Build for the Art of it!
If you can get cedar it would be better. But if not, you can use white pine or Douglas fir. I would recommend coating pine or fir with teak oil to protect it from the weather.
4x4's are notorious for twisting, especially in the longer lengths. Are these posts to be buried, or is the structure free-standing on a concrete or gravel pad?
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
I'd look for DF or Cedar, both are rot resistant ant paintable.
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whatever you use you might want to get post anchors that keep wood two or more inches above ground levelalso many considerations but 6 X 6' posts look real good w/ 2 x 6' horizontal members