Constructing with poplar
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Is poplar appropriate for building? February 6, 2002
Question
I am cutting poplar 2 x 6's. Anyone have tips on using this lumber in construction?
Forum Responses
It is an acceptable species for using in construction and can be graded using the softwood rules. However, very few people are certified to grade poplar. You may have to sell it as a utility wood rather than graded wood.
Gene Wengert, forum technical advisor
Poplar cuts pretty easy but it will get harder to drive nails as it dries. I have been told that it is considered a hardwood?
Are you cutting for your own use? Most recently I cut my 2x6's 6/4 by 6". I stacked them on edge on sticks and let them dry a while. Now I am bringing them back and recutting to 5 1/2". I think next time on 12' and longer 2x6's I might cut 6 1/4 or 6 3/8. That would allow a little more margin to cut out some bow. I am using my clearest logs for joists, slightly knottier for studs, etc. Everything will be yellow poplar in my new addition with the exception of second story floor joists where I needed to span 24'.
I cut poplar and white pine for studs for exterior walls in some rent houses. Poplar tends to bow, but the stacking on edge would help stop that.
On all my studs, including the 2x4s I use on interior walls, I cut on a bandmill inch scale, so the lumber actually comes out about 1 7/8" thick and 3 7/8 or 5 7/8" wide. After they air dry to 20% or less, I take them to my shop, precut them to 93", run one edge on a long bed jointer, then rip them on a table saw to exactly 3 1/2 or 5 1/2 width. You get a nice straight stud this way. I don't worry about the extra thickness--just leave it, it makes the stud that much stronger.
I bundle them in stacks of 60-80 (because that's the load limit of my tractor front loader), run some shrink wrap around the ends to bind the bundle, and stack in a shed until the next house is under way. Takes a little extra work, but I can run 250-300 in a day, so in 2-3 days, I have all the studs I need for 1200-1500 sqft house.
The term poplar can refer to either yellow-poplar or to aspen poplar. The two are not related. Aspen is the softest hardwood in North America (of commercial importance). Yellow-poplar is much more dense and is also called tulip poplar. It is the tree that replaced chestnut in much of the Eastern forests.
Both hardwood species are approved for construction grading. (Hardwood means a leaf bearing tree and does not refer to the hardness of the wood.)
Aspen poplar likes to dry easily if sapwood. Heartwood dries much more slowly, with collapse in the heartwood, at times. Warp is seldom a problem. It is about 1/2 the weight of oak.
Yellow-poplar is easy to dry. However, y-p has growth stresses that cause considerable warp before, during, and after drying.
Gene Wengert, forum technical advisor
Most of the aspen up here also twists on drying if not weighted. I put it on the bottom of stacks, but it will sometimes spring anyway. It is not like hickory, which tells you it is going to bend. It waits till it is dry.
Our bigtooth aspen is prone to warping. We've clamped and spiked stickered piles to keep it from warping. Best thing to do with it is build with it fresh off the mill. Did my house this way with bigtooth. Cut the trees first day, sawed the logs the next and nailed the stuff together on the third day with ardox nails. Everything stayed straight. Let the house dry about six months before I hung any drywall. I sawed some bigtooth 2x4s last summer for pole barn purlins. They were straight when sawed but twisted in the week before we used them. Had to cull a few.
What are ardox nails? Also, would tulip poplar be any good to stain?
Ardox nails are spiraled or twisted. Makes 'em pull out hard. I usually break them off when trying to pull them.
I spent several weeks at a mill in northern Wisconsin working on drying aspen and we did not have any twist or warp, except in a rare piece. This was trembling aspen. We also used a good kiln schedule and good stacking. We did not try to dry the "heart".
As most folks know, aspen is a very soft wood. To nail it well, you need to use more nails to get the required nail holding power and also nails with larger heads so that the heads do not pull through.
I believe that ardox nails are also casehardened, in addition to being spiral shank. This means that they do not bend easily. This property is important in a product such as pallets where the nails will be under shock loads at times (like when the lift truck runs into the pallet a little too hard).
Gene Wengert, forum technical advisor
Bigtooth aspen is soft when green but when it's dry, it's hard to drive nails into it.
Out here in Oregon, I have sawed it for horse people to use for stalls and fencing. Horses will not crib on cottonwood because it is too bitter. This could be a new market for you to try.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor A:
I used 2x8 poplar for most of my floor joists. All were air dried. They work great and are very strong and straight. I would discourage cutting smaller dimensions in poplar as it does warp easily (i.e. no 2x4's).
Comment from contributor B:
Yellow poplar is a very good wood for making 2x4's, 2x6's, and boards. I have a Woodmizer sawmill for cutting my own lumber. What I like to do is cut 2x8's and let them air dry for a year if possible. Then I put them back on the sawmill and split them down the middle. Then I put the cut side back on the sawmill and cut them down to 3 and 1/2 inches wide. This way I have almost perfectly straight 2x4's. I might cut 2x6's 6 to 7 inches wide and then after they have air dried good I cut them down to 5 and 1/2 inches wide.
Comment from contributor C:
The time of year that the popple trees are harvested seems to have some impact on how much the lumber twists as it dries. I have sawn popple using a chainsaw mill, and the logs that were harvested in the fall after all growth for the year was complete seem to yield wood lumber that doesn't twist as much as logs harvested in mid-June.
