New T & G pine floorboards fitted - are gaps acceptable?

[MrRichT]

Hi all, about two months ago we had our old downstairs floorboards replaced due to a nasty woodworm attack. The builders treated the joists and laid new tongue and groove pine floorboards as requested. However, they didn't allow the boards to acclimatise to the rooms before fitting, which I wondered at the time whether that would be a problem.
Now a couple of months on there are gaps between nearly all of the boards, but probably not more than 1mm except for the odd few that are maybe 2mm. Also, some boards are still creaking.

Basically I just wondered if I am worrying unnecessarily, and that it's normal for the boards to expand and contract by a mm or two during the winter/summer months. Or whether the builders were wrong not to leave the boards to afjust to the room for a few days before fitting and now the boards will never be right? I've taken a picture of some of the larger gaps below.

Any advice greatly appreciated, thanks.

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[ladylola]

There's probably not a floor in the country without a gap or two somewhere except maybe for the engineered ones. I wouldn't see it as a problem at all 1-2mm is nothing to worry about.
As to aclimatising the boards then a couple of days wouldn't have made an jot of difference. Several weeks at least are needed and preferably a couple of three months to be anywahere "safe" , which is fine if you don't mind having to live with a dirty great pile of boards in the house for months.

 

[gregers]

did they use any floor clamps?

whenever ive done floors like these i wind the clamps up,that way when they shrink its should still be tight,did they spray the boards before fitting or do it as they went?

 

[MrRichT]

Yeah living with the boards lying around wasn't really an option for that long as I have young children.

They used clamps yes. They treated the joists but not the boards themselves, they said they wouldn't need treating for some reason. Maybe the type of wood, or would they be pre-treated?

 

[AronSearle]

That kind of softwood flooring is sold in a lot of builders merchants, mainly with the intention of being carpeted over, so the moisture content is not tightly controlled, and they are often sold at approx 14% moisture content, they are likely now about 10%, giving you the 1-2mm shrinkage per board that you have.

If they are approx 20-25mm thick, then providing they were properly stacked, 7-14 days would have been enough for them to acclimatise to the ambient conditions.

Treatment is not necessary, I assume you had some damp issue, if that has been fixed and the boards are dry, there is almost no risk of another insect attack.

The squeaking is likely caused by boards either rubbing on the shanks of the fixing, against each other, or if the joists are not level to each other, the top of the joist as the boards flex. As the boards have shrunk it is most likely that they need re-tightening, which obviously isn't practicle with nails.

 

[MrRichT]

That kind of softwood flooring is sold in a lot of builders merchants, mainly with the intention of being carpeted over, so the moisture content is not tightly controlled, and they are often sold at approx 14% moisture content, they are likely now about 10%, giving you the 1-2mm shrinkage per board that you have.

If they are approx 20-25mm thick, then providing they were properly stacked, 7-14 days would have been enough for them to acclimatise to the ambient conditions.

Treatment is not necessary, I assume you had some damp issue, if that has been fixed and the boards are dry, there is almost no risk of another insect attack.

The squeaking is likely caused by boards either rubbing on the shanks of the fixing, against each other, or if the joists are not level to each other, the top of the joist as the boards flex. As the boards have shrunk it is most likely that they need re-tightening, which obviously isn't practicle with nails.

Thanks very much for that. Is my best option with the creaking ones then to go round and make sure they are completely nailed down and maybe put a few more nails in them? Also I've read talcum powder is good for stopping creaks, worth a try?! At the end of the day we are just going to carpet over them anyway, so as long as they don't creak and there's no risk of further insect infestation then I'm happy.

Oh, as for the damp, yes there was a leaking radiator in the bedroom above which caused some damage. Also a small amount of damp on the sub floor and exterior wall, possibly linked to a flat roofed outhouse the other side I'm guessing. We've since had all new central heating installed, new electrics and had all old pipework etc removed. I think the house is slowly drying out, the previous owner (an 80 yr old man) hardly ever put the heating on and when we moved in we noticed the condensation was really bad but that's improved loads with the new central heating.

 

[AronSearle]

With the creaks, it depends exactly why they are happening.

It is most likely down to play around the shank of the nail (the board rubbing up and down the nail shank).

find a board that is creaking, and put some water or oil around the nail as a lubricant to see if that is what is causing it. If so they screw down the affected areas rather than put in extra nails.

It may be that the boards are rubbing against each other, rather than the nail, but the remedial action is generally the same as above.

With damp in the sub floor, I am guessing you have a suspended floor. Providing this is properly ventilated, then the level of heating doesn't matter. Was the outhouse built onto the side of the house, blocking the air bricks?

 

[MrRichT]

Thanks, I'll try that.


Yes it's a suspended floor, the outhouses have been there since the house was built. They don't block the airbricks, in fact the ventilation is pretty good and there seems to be enough air bricks around.