Flooring Advice

[Brian_Weekley]

Looking for some advice regarding flooring...  I have a stack of 1-1/2" x 6" boards that I plan to use as flooring in my timber frame barn.  They've been air drying for several years.  I'm debating whether to tongue and groove them or use splines.  Since I'm doing these myself, I'm thinking splines would probably be easier since I can run both sides of the boards through a similar process (e.g., dado blade on radial arm saw).  

However, I have a few questions:  Are there any advantages/disadvantages between splines and T&G?  Any recommendations on spline size for 1-1/2" thick pine flooring (thickness and length)?  Should the splines be hardwood?  Is the grain direction of the splines important?





Test run using a molding head to T&G:





Thanks for any feedback.

[Southside]

Since you can T+G I would go that route, one less thing to have to make, install, etc.  If you go spline then I would not mix species since that could amplify any seasonal movement issues if the two woods move at a different rate.  I suppose a guy could use a floor nailer with a spline but if that spline moves while nailing, then you have an issue, not the case with T+G/  Just my $0.02

[Brian_Weekley]

Thanks.  A few other points:  i'll Be face nailing the boards down with cut nails (so no nails through the splines).  My T&G cutters only have a thickness capacity of 1".  Therefore, it is quite labor intensive with my setup (cutting grooves on one side, cutting tongues on the other, and then a separate rip cut to remove the extra 1/2" that the tongue cutter can't reach).  That's why cutting just grooves on both sides of the board for splines would be much easier and faster (although you also need to cut the splines).

[Southside]

What would a new set of cutters cost? I can run the heads from my 4000 on my shaper so a new profile is just a pair of knives. 

[Brian_Weekley]

Lucky you, but I don't happen to have a Woodmaster or a shaper.  What I showed was using a molding head on a RAS.  It works great, but the T&G knives available for that are only 1" wide.  I'm really just trying to establish if there's any mechanical or practical disadvantage to using splines instead of T&G.  I've seen people make floors with both.

[Southside]

Oh, looked like a shaper. 

[Don P]

devil's advocate without anything more, the spline would double the gap slop during dry times compared to T&G, not sure if that matters.

[DDW_OR]

how about a lap joint? I would use type B
A


B

 

[Bruno of NH]

I'm in late to this
Use plywood for the splines and wood glue to one groove then push in the plywood spline and let it float in the adjoining groove.
I have good luck doing it that way in the past.

[Brian_Weekley]

Thanks all for the advice. The shiplap would be OK if it was going over a subfloor, but since the boards will be laid across joists with crawl space below, I don't want to go that route.  I think grooves and splines would be the easiest for me to cut and would provide both strength and sealing.  Bruno- thanks for the plywood suggestion.  I hadn't thought of using that for splines, but that would be a uniform material to use.

[Southside]

I had a house where the original owner had laid down a ship lap, pine floor that must not have been kiln dried.  Face nailed and about every board was either bowed or cupped, not to mention the shrink gaps which would fill with dirt.  Could not sand it flat, had to use a power hand plane to get it somewhat flat, it was never a great floor.   

[Bruno of NH]

I used a solid multi ply
Like Baltic birch 
Something with no voids