Here is my situation: I really want to lay an aspen floor in an outdoor screened porch, but the boards are at 6% MC while the porch is at probably 12-15% MC. My instinct is to just sticker the boards and wait… but I really wish I could lay this floor NOW.
I was thinking that if I knew the exact expansion rate for aspen going from 6% to 15% I could calculate the expected swelling for each board and make shims of that size to create that spacing between each board as I build the floor.
Since the boards are only nailed through the tung, they would be free to expand into the grooves as the moisture increases gradually to 15%
So… Is this totally insane? Has anyone tried it?
If you all tell me to just wait, I will. If someone has done this with success, I would love to hear about it.
Replies
Your solution will work, in theory, but maintaing an even gap will be hard if the boards aren't very straight. Laying the boards when they are at a high MC allows you to drive them tight together as you nail them.
The expansion is easily calculated, I just need to know the width of the boards and whether they are flatsawn or quarter sawn.
These won't get rained on, which would push the possible MC higher? I don't believe aspen holds up well in exposed locations, so hopefully the floor won't be getting rain on it regularly.
John White, Shop Manger, Fine Woodworking Magazine
The boards will be protected from rain- The porch has full windows that open to screens when the weather is nice. We were also planning to paint the boards once they hit an equilibrium in MC. This will further protect them. The bottoms have milled grooves to allow air movement through the floor. The location is between bloomington and indianapolis Indiana. The width is about 4 1/2" per board. It was flitch sawn on a bandsaw mill, so it contains some quarter sawn and some radial pieces.
They were made into flooring on a large all in one machine which joints the boards, so most are very straight.
Most of the stable air dried lumber in this area measures 15-16% MC during the summer on two different moisture gauges. The aspen was kiln dried in a Nyle dehumidification kiln to 6% MC. Let me know if you need any further information.
Thanks for your help-Vincent
Vincent,
My Lee Valley reference guide says flat sawn aspen expands .0023" per inch of width per 1% moisture change. So the number would be 4.5 times .0023 times 10 =.104", a bit under 1/8 inch. Quarter sawn moves half that much.
The Lee Valley guide is a good tool to have, it is very well designed to find the information quickly.
John W.
Vincent
Theory is wonderful stuff...if you are an academic. You sir, are a player of Russian roulette! Give it a try, if you are prepared to live with the consequences that there surely will be. One thing is certain, you will have plenty to analyze and think about after the fact. By the way, you did say that you verified the moisture level of each board, in several locations along the board, and that the density of the boards are exactly the same throughout? I am maybe imagining this. :-)
People who take chances are either at the head of the field, or at the tail end of the crowd...rarely are they in the middle of the great mass. I truly wish you good luck and success. JL
jeanlou-The good news here is that this is a project that I am working on with a friend. It's his house, his floor, and his crazy idea to rush the job. Personally, were it my home/time/wood, I wouldn't take the risk unless several people had tried the same thing and reported success.But my friend is that roll the dice, i can't wait type... so I just want to give him the best advice possible and learn from the results. And yes, we will be checking these boards extensively with a $300 moisture meter (it's worth more than the wood for the floor!) which takes readings into the center of the board, and double checking them with a pin meter as well. hmmm.... so for a 12 foot wide room, we have about 3.4 inches of movement. Seems like it could work so long as we allow 1/8 inch for each board to move.
Vince
Let me think out loud here. You nail the boards through the tongues so that the board can expand about 1/8 of an inch on its groove side as it slides on to the tongue. If the Aspen was machined as most floors are, then you have a little over 1/16 of an inch of joining of the boards (tongue into groove) before they start to swell with the introduction of the ambient moisture. You are a gambler.
How about this idea. Put the wood in a closed room and install a humidifier. When the moisture level in the room reaches the ambient level of the location you want to install in, keep the humidity level constant for a few days as the flooring material expands, and you can install your flooring tight.
If you work quickly, the porch floor will be installed in a long day and Bob is your uncle. I think it beats spinning the cylinder of the pistol as you play the roulette game. Just a thought. JL
I like to take risks once in a while, but I always try to stack the deck in my favor as much as possible.
I don't recall the last time that the installation instructions for wood flooring didn't say to place the flooring in the environment that will be it final resting place, or word to that effect.
Is that possible to do? If inconvenient, can you split the job in half?
If possible you might check the NOFMA site. Just google it and you'll find it.
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
When I think of wood for flooring, aspen comes in one step above balsa wood. It is very soft stuff an I doubt it will last worth a dang. It makes great wall covering but not for a floor
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