Floor laying problem

[dave]

I have taken up my circa 1904 house lounge T&G suspended floor, because it was really rough and damaged, and I am putting in 100mm of Urethane insulation between joists and then a new T&G floor, perhaps Oak if I can afford, back onto original joists which I have treated for wood worm and dry rot. My question is does anyone have experience of "Hidden Nailing" floor boards. I have used this technique on T&G on wall cladding, but wonder if I will get sufficient HOLD with the nails, to stop creaks and movement etc., bearing in mind that normally floor boards are nailed with two nails per joist into full thickness. With hidden nailing there would be only one nail per joist into a reduced thickness wood. My local wood yard says it will give me extended grooves to help with hidden nailing, but can't advise me on its suitability for the job or its strength. If I put down Oak at £ 40 per Metre, I don't want to have try to take it up without damage, to make adjustments. Any carpentery experts out there please help!

Dave

[The3rd Earl Of Derby]

Nailing T&G flooring is why creaks become apparent,only screwing it down will stop creaks. What happens is continuous traffic over time loosens the nails slightly and sufficient movement occurs in btween joist and floorboard. As for the method of blind nailing I'm suspicious as to whether this will be enough strenght to keep the T&G in place at all as the differing climates will swell and shrink the T&G over time.

I'd go for normal nailing and put rubber matting underneath ie 1/16th strip rubber matting tacked on top of each joist to dampen the creaking.

[davej]

Hi ,the timber shrinks across the grain-only one nail will let it move which will widen any gaps as it dries but should lessen creaking, so let the timber dry out and acclimatise to your room.The insulation will make the room warmer/drier so try and store the timber in warm conditions (upstairs?) for a few days.The joists also shrink and swell which contributes to creaking noises in the night