Replacing T&G floorboards - always lipping on one edge?

9 May 2009
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United Kingdom

Looking for a little expert advice if possible.

Georgian house. Have lifted entire room of tongue & groove pine floorboards and am replacing them with reclaimed floorboards, also pine, and left in the room to acclimatise for a few weeks.

I have run the reclaimed boards through my thicknesser to renew them. I've only done the face side, and all to the same thickness (obviously).

I'm fitting them using floorboard clamps (the ones that grip the joist and push the board snugly on to the previous one) in combination with cauls cut from the grooved edge of some offcuts, and a first fix nail gun with 65mm ring shank nails at about 45 degrees through the tongues.

As I'm fitting the boards I'm finding that they are lipping badly, with the new board's edge always rising higher than the adjoining edge of the previous one by a millimetre or so; sometimes even two.

I've got the gun set so that it doesn't smash the tongue, and I'm driving the final few mm manually with a hammer and punch. I've made sure I'm punching the nails through far enough that they're not fouling the T&G.

I'm pretty sure I'm not over-clamping. Have tried reducing the clamping pressure but that doesn't help - I end up with a gap as well as a lip which if anything makes it more obvious.

I guessed that being reclaimed Victorian boards there might be a bit of inconsistency in the T&G machining, so I've measured to double check and they seem fine. Plus, the fact that they're all lipping high on the same edge rather than being a variety of high/low seems to point to something I'm doing wrong rather than any variation in the T&G.

If it comes to it I can just go over the floor with a sander afterwards but having gone to all the effort of planing the boards I'd rather not have to.

I've tried googling for answers but everyone's talking about modern manufactured flooring systems designed to go on top of a subfloor, not replacing actual floorboards.

Any and all advice greatly appreciated. I'm stumped as to why this is happening.

Bruce L
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yes a cirius says you need the exact same profile to match a step means a mismatch with the thickness or txg position on the planks holding the boards out off level
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Presume the problem is, once you've nailed through the tongue, it's tight to the joist/floor, when you slot the next floorboard on it, if the T&G's don't match well it will be as loose fit and raise slightly when it's nailed down tightly.

Not sure you can get around this easily, think I'd get the sander out... at least by thicknessing them, you've got a good start.
20mm board 7mm above and below a 6mm tongue
20mm board 6mm above and 8mm below a 6mm tounge
also worth checking the settings on the planer thicknesser bed and blades parallel the full length accurately measure a board both sides

i am assuming by lipping he means the boards not going together level??
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T&G boards are normally machined with more depth of wood above the tongue than below. In the old days, this was to allow for wear on the top surface of the board, when floorboards were usually left exposed and scrubbed regularly. If they have been through a thicknesser, without checking that they have all gone through on the 'right' surface, this might cause problems when laying?
Hi all and thanks for the helpful replies.

In the end it turned out that there were indeed inconsistencies in the machining, so whilst they were all identical thickness (and all thicknessed down on the same side) the T&G wasn't always matching up as well as it had seemed from my random checks of a few boards.

The machining issue was also compounded by a couple of other factors: the joists are fairly uneven and in one case badly twisted (going by the original nail holes it looks like it had been that way from the day it was put down) and, as Mr Chibs mentioned, the adjoining board already being nailed down tightly didn't help matters. Finally even before nailing them down the T&G was always a very tight fit despite them all having their century of accumulated dirt thoroughly scraped out!

I think I just needed to rein in my expectations a bit. After having thicknessed the boards and done a few test fits I was expecting close to perfection when they went down, which was perhaps a little bit optimistic for hundred-year-old reclaimed boards. This was the first room out of six that I'll be doing so I'll know what to expect for the rest and be a bit better prepared.

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