Gaps in floorboards

[kyeko]

Hello all
I have old wooden floorboards and at some of the joints they have separated enough to leave a gap where you can see through to the ground.The gap would be about 2-3mm, which is not good in winter with the cold draft coming through. Does anybody know the best way to seal the joint underneath the floor.
Thanks Kyeko

[silentC]

I used Fuller's Caulk in Colours. Squirted into the gap from below. Water clean up if any comes through above. Easy fix. You need something flexible.

[Tools]

If you can see right through,what has happened to the tongue?

Tools

[glock40sw]

G'day.
Some old floors were square dressed with no T&G.
Very rare to find them now.

[kyeko]

The tongue is quite small but is visible as well as the gap.

[Spreyton22]

I've also used Fuller's Caulk in Colours. Worked well, but tended to shrink in a bit.
It can be bit messy ... We found it best to put a first "sealer coat" of whatever finish you were using on the boards, then apply the gap sealer (and rub off the excess ...)



And then wipe it with a soft, damp cloth !

[OBBob]

I used a clear waterbased silicone sealer (think it was Fuller too) that goes on white and dries clear. It's fantastic becasue you can see what you are doing and make sure you get it all off teh surface prior to drying.