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View Full Version : Flooring- tongue and groove versus splined joint.



Malcolm Schweizer
11-10-2014, 2:00 PM
I'll try to keep this short and to be nice, but I do need to explain how I got into this mess. My neighbor is restoring a beautiful old home built in 1803, and unfortunately he has done everything completely wrong. I am now going to try to help him salvage what he has done. I love the guy. He's very nice, and well-intended, but he doesn't know a thing about restoring a house as far as the technical aspects, and did everything the way he thought it should be done, which is basically the absolute wrong way.

My neighbor wanted to refinish his original heart pine 200 year-old floors, but he wanted to put a subfloor in under it. Why? Well he wanted to make it sound proof, and he also wanted to put a waterproof layer of tar paper under it. By the way, he not only put tar paper in the subfloor, but he had the tar paper go 6" up the wall under the baseboard, in his words, "so that if water ever gets in it can't do any damage." Right- so now you have a wading pool for a subfloor- that seems safe. Read again the first paragraph- that's all I can say. So this floor has lasted 200 years just fine- maybe a few termite holes, divots, and what-not (read: It had lots of character), but otherwise it's held up 200 years. Then my neighbor decides the best way to refinish the floors was to pull them all up. When I say pull them up, I mean with a crowbar, ripping all the nails out, and tearing every board at the edges. It is quite the mess.

The wood is now sitting in a ghastly looking pile at the workshop where I volunteer teach. He is expecting the boards to magically be run through the board fixing machine and come out nice and shiny with the exact same amount of board feet that he started out with. (If this doesn't make sense, please, once again, read paragraph 1). To be honest, I want him to realize this is futile and give me all the wood to make furniture and boats out of, but I feel like what he did was so abominable that I actually want to at least try to salvage what I can and get him maybe enough wood to finish the greatroom. It would be my woodworking karma to at least put as much of the wood back into the home as I can. I literally imgaine the original craftsmen looking down from above, crying as he pulled... no... RIPPED each board from its place. The creaking of the boards was their screams.

So I have to take each board, true up the jagged edges (and believe me, it's so bad that I could more easily resaw a log into lumber than fix what is here), and route a tongue and groove. Ahhh, but in order to get the most board feet out of this pile of splinters, I was thinking about doing a splined joint. Much harder to install, but I would gain a little bit more width per board (not much, but every bit counts) and the setup would be much simpler to do a groove on each edge than to do a tongue and groove.

So the question is- Other than a more difficult install, is there a reason not to do a splined wood floor in order to make the most of the small amount of wood I will have to work with?

roger wiegand
11-10-2014, 2:53 PM
No, splines work fine. Just don't glue them in on both sides so wood movement can happen across the whole floor, not just at selected weak points. Most 200 YO floors didn't use T&G, but were just butted together. Any reason not to stay authentic?

Malcolm Schweizer
11-10-2014, 5:06 PM
Well honestly I didn't think it would be good to butt join floorboards. The originals are tongue and groove. This guy put two layers of 1/2" ply down, so certainly there is no need structurally- the wood is now really more for looks now. Originally, however, it was just wood and no subfloor so the bottom if the wood made the ceiling for the lower level of the split level. Thank goodness he didn't mess with the third floor.

Tom M King
11-10-2014, 6:28 PM
Are the boards not hand hewn under the bottom, and notched over each joist? How thick are they? Most floors I've dealt with like this had an inch and a half as the minimum thickness over the joists. What kind of wood?

Malcolm Schweizer
11-10-2014, 7:25 PM
This is heart pine that originally came from N Carolina. I am not sure what kind of pine, but it is deep orange. They say it is pitch pine. The beAms are for sure pitch pine, but not so sure about the floors. The Virgin Iands were a stopover for ships going either direction and they likely dropped off lumber and picked up other goods. I have to measure, but it is only about 1" thick and was nailed directly over large timber frames.

Tom M King
11-10-2014, 10:04 PM
I'd like to see a picture of it. Were they sawn on top and bottom? Probably Long Leaf Heart Pine. They were trees that were standing here when the country was first settled. Look at the woodwork page of my website, and you will see some repairs of a similar floor. although that one is hewn on the bottom. They are tongue and groove. That's the only way I've seen 18th and early 19th Century floors around here. We had to buy some 20 foot long boards to let in 3/4" on the top to replace some rotten parts.

Malcolm Schweizer
11-11-2014, 3:17 AM
Yes- sawn top and bottom and the bottom is the ceiling for the lower floor. My house has the same pine from the same lumber yard (the beams in the attic are stenciled). I don't have a shot of his but have one of my floors finished. The beams are pitch pine. When you drill into them they are still sappy inside. Termites won't touch the beams.

300066

Tom M King
11-11-2014, 7:53 AM
Those beams are probably the center of the Long Leaf Pine trees from back then. http://en.wikipedia.org/wiki/Naval_stores I know a lot of people call this resinous wood "Pitch Pine", but it's probably not: http://en.wikipedia.org/wiki/Pinus_rigida

I worked on a 1777 house, down near Wilmington, N.C., that had been sitting on 3 foot cubes of heart cypress since it was built 200 years ago. I'm sure sitting directly on sand had something to do with their longevity too, but termites had never been through those cubes. Where a new porch was built on one back corner of the house in the 20th Century, termites had found a path to the house, and that whole back corner of the house was destroyed by the termites.

greg Forster
11-11-2014, 4:08 PM
interesting topic; next time you're up in the attic, I'd sure like a photo of the stencils ( and the roof framing)
I'm about to pry up my T&G floor to gain access for structural repairs; I've done this in the past using wedges, just can't remember if you work from the tongue
direction or the groove side-I'll have to re-educate myself.

I've run into the flooring similar to what Tom mentioned, on a job in SC(also Roy Underhill has some info in one of his early books)
This flooring was about1-1/4" thick with a rabbet run along one bottom edge,gauged from top edge of each board, then at each point it "hit" a floor joist, the floor board was adzed to that gauge rabbet