Solid oak floor buckling badly

[Usermaatra]

I had a solid oak floor laid 6 weeks ago. In the last two weeks it has buckled to a height of 3 inches! Had the installer back and he reckons there is damp underneath the house. His damp meter read 18 in some places but only 9 in others. He left a 5mm expansion gap when he did the job (with glue).

Went to my neighbours house where they have oak flooring with no problems (a bit of cupping but still looks lovely). Damp reading 20 in some places, 7 in others, so roughly the same. Their installer left 12mm gap and used nails.

My installer says that even if they'd left 10mm or 12mm the boards still would not have had enough space to expand as the buckling is so high. Is this true?

 

[mattysupra]

The moister reading they are using is not a british standard test if testing the subfloor. The test takes a minimum of 24hrs and is done using a hygrometer. The subfloor needs to read below 75%rh to BS but really needs to be about 60%rh and lower. (minimum would be maybe 40%rh)The only test that can give readings of 9,12,18 etc is a wood moister content test.

I say this taken that it is a concrete floor? If it is a wooden subfloor and they are taken readings of 9,12 etc then this is correct but this should of been taken before the flooring was fitted!

And yes 5mm is not the correct expansion unless your room is under 2 meters wide?

At the end of the day unless there has been a flood or major movement/subsidence in the last few weeks then the installer has made a mistake. They can blame your subfloor saying it has damp but they to british standards should not of fitted on it without carrying out neccessary works first.

Any pictures avalible as this maybe nothing to do with moister?

 

[Usermaatra]

Thanks for reply.

The sub-floor is wood and the crawl space underneath is dirt, and you're right, he used a wood moisture content meter to test the sub-floor.

The room is 4 x 3 m and it's not the only place the floor is buckling; it's started in the lounge and hallway too! The fitter has agreed to put right if it's his fault.

 

[mattysupra]

o.k then, there reading of 9 is fine but 14+ is to high. If your wooden subfloor has readings this high it is down to two things.

1- most commen! the air bricks are blocked or the crawl space is full of rubble or the air bricks are not bid enough or they have the incorrect flow leaving dead spots. Basically the air flow under the house is not correct!

Check for blocked air bricks, they should be on opposite sides of the house to each other with nothing blocking airfloor under the floor either. Maybe some one has build a conservatory on the back of the house and blocked air bricks? Flower bed maybe?

2- next problem could be that the joists are incontact with moister, no dpc/dpm between the joists and where they sit on walls etc. This will cause moister to move down the joists into the floorboards, should be wetter at the edges than the middle.

If this is the problem then you need to add a dpm/dpc under the joists or where in contact with earth etc.

One other question, how long was the wood acclimatized for?

 

[Usermaatra]

Airbricks not obstructed outside but I will look at joists again tomorrow.
Some did LOOK damp near bay but did not feel particularly damp or wet, which was strange. Wall wasn't damp either.

Now have a hygrometer to test the humidity in crawl space this weekend.
I think a surveyor is the best route to find out what is happening. If a dpc is recommended then I'll have to go with that and use a dehumidifier in the meantime to move out moisture. If they say something else, it's round 2 for the floor installer.