I’m building a log house. The floor is supported by log joists on 48″ centers. The typical way of building this floor is to use 2×6 t&g decking. The owner’s wife likes the look of wider floor boards, so I’m using 2×10 lumber. I cut slots in both sides of the boards and installed a 1/2″ thick plywood spline to act as a tongue.
A common problem with this type of floor system is that dirt and crud filters through the t&g and falls on the kitchen counter below. I’m proposing to glue the floor together to keep dirt from migrating through. I’m also considering face screwing the boards to the joists to minimize movement.
OK, now for the question. What is the potential risk of these wide boards cracking if I restrain them as much as I’m considering? The actual width of the board is just under 9″ and they have been stickered inside for about two months.
Thanks for all of your help.
Tony
Replies
Yup..it'll crack. I have a log home..well seasoned at almost 2 centuries old..but neither here nor there in this case..it will crack.
IF you mill the splines deep enough ( my router slot cutter will go 1/2'' deep IIRC) that should eliminate dirt seepage past the joints..else wise, use a table saw or shaper to get the width of the splines as wide as you can.
If you face screw ( ferget the glue, it won't do much good) elongate the bores so that the screw has some slop , so when the inevitable shrink and expand of the plank happens, the wood is not constrained.
A bit of time spent on them holes will solve a LOT of time later on. A 3/4" plug will hide the oblong screw holes just fine..if ya have a plunge router just Cbore the holes witha 3/4 bit..BEFORE ya drive the screws..that same router can with a jig, make the through bores be elongated witha 3/16 or 1/4 bit. Depends on the screws..I'd opt for a #12x3 screws.
The other problem you will run into that makes this unsuitable IMO for interior flooring, is that with fewer joints and wider lumber, there will be more force within the wood to reckon with . that greater force will focus itself on the joints. So you end up with a larger yank attacking a smaller joint. Ove four foot spans there will be not5iceable movement and cupping.
You also don't mention species. Most wood used like this for T&G decks is pine which wants to lay flat once fastened in, but the 2x10 framing lumber is more likely spruce or fir. Some fir is fairly stanble, but the knots drip resin. Spruce will chase it's own tail in a circle.
To deal with the problem you mention, we lay a ply of homasote over the 2x6 T&G. then a finish floor
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Any reason you can`t install some type of subflooring prior to the 2x flooring install to keep dust/debris from falling through?
Plybead or t-111 might even give you a nice look from the underside.
I`d avoid glue.....it`ll just add to the splitting of the flooring.
J. D. Reynolds
Home Improvements
You shouldn't have significant problems if the lumber is dry and your interior moisture levels don't change much. In the rocky mountain states you'd be fine since our wood moisture in residential structures stays remarkably consistent. Anywhere else is outside of my sphere so to speak.
If you install the wood in an oversize state and it shrinks, so what? The boards shrink away from each other, that's about it other than cupping.
Watch grain direction so the boards don't cup up at the edges and place screws about 4" apart centered in the middle. There's no more risk of splitting than if attaching 2x6s near the edges.
We've built window and door bucks from wood in the 25% range that are about the width of what you're talking about and they dried quite fine installed.
To keep the dirt from falling into the area below why not crack one of those chink buckets and run a small bead on the top side of the joint. Today's chink stretches so much I'd be surprised if it pulled away when the boards are completely dry.
If you're building in Manhattan mileage may vary. :-)
Don