Bubbles under vinyl - advice please

[Marion1977]

Hi
Back in the summer I had to remove a carpet, as the lovely wool underlay had, over the 16 years it was down, absorbed moisture from below and I had damp/mould in the alcoves either side of the fire place. At the time, I asked RentoKill to come and have a look - they said I did not have a damp problem.

The floorboards were then bare for 4 months, dry and not smelling at all. I have a dehumidifier on constantly.

I asked a local store to fit vinyl, for a change.

They came out, said my floorboards were not flat enough (ok, it's a 1901 house and there were some slopes), and that putting vinyl straight on these would cause it to rip in time. They suggested hardboard going down first, and I was happy to let them do this. They also put the vinyl down at the same time.

24 hours later, there was a bubble under the vinyl. Two weeks later, there are multiple bumps and ridges. I have asked the company to come back and replace, and they are saying that the problem has been caused by damp (without looking!).

My question is (which I think I know the answer to, but I need some support here) - would hardboard absorb damp overnight to the point of bubbling up? The bubbles are in the middle of the floor, not where the original problem was.
Also, what would be the solution - just laying new hardboard/vinyl or do I need to put a layer of some sort down? (reading other posts suggests this is not recommended) I just need to know, really, before I shell out money that I don't need to spend.

The photo is not very good, it's hard to show the bumps!

Thank you

 

[JohnD]

damp can make hardboard bubble. It is correct to moisten it the day before laying so it has a chance to tighten flat as it dries. Are you sure the airbricks to ventilate the subfloor are clear, and there is no leak from e.g. radiator pipes?

Thin ply is preferable, but costs more.

Vinyl will also go into bubbles under the castors of, say, an armchair, because it is stretches when you move the chair around.

 

[Marion1977]

Thanks. There is no leak, and air bricks are clear. Would hardboard really bubble in under 24 hours? and this occurred before I had returned the furniture to the room.

 

[Marion1977]

//www.diynot.com/diy/threads/hardboard-bubble-or-buckle.142610/ a bit more searching suggests that this might be my problem... I have contacted the shop again, and await a reply

 

[dazlight]

What was the moisture content in the floorboards before fittings?
Do fitters still use hardboard ? I haven't in 20 years. Ply all the way.

 

[Marion1977]

I don't know, I wasn't home when it was done. Shalln't be making that mistake again! Would ply do the same if fitted too tightly?

 

[dazlight]

No it should t if using a good plywood like SP101

 

[Marion1977]

thank you, very helpful

 

[Doggit]

Now this is an interesting thread. I've often put hardboard down before laying ether vinyl, or carpets, and I've never dampened it, as I've never heard of the trick before, but none of my hardboard has bubbled since I started using 1" ring shank nails at 150 to 200 centres. And unlike the pictures, I was taught to lay it smooth side down, as that gets you a better grip with whatever you're laying on top of it.

Moisture certainly wouldn't cause a problem within a day, as I've just had to take up some vinyl flooring where the hardboard got wet from a leaking pipe over the coarse of a month, and then bubbled.

What thickness ply do you use Dazlight, and how do you fit it please.

 

[dazlight]

Mostly use SP101 5.5mm now and then 9mm
We smooth floorboards if needed with a plane or belt sander
Then lay ply with nail gun and compressor with 19mm or 22mm ring shanks.

The feather finish screed or if bumpy we use a fibre smoothing compound.

 

[Doggit]

Wow, whole new ball game; thanks for that Dazlight. Sod it, just given the belt sander away because I never use it.

 

[Marion1977]

Just dropping in to say thanks to those that took the time to respond. The company finally(!) were able to come and have a look yesterday. Not only were the boards cut too big, they weren't stapled into place either!
Now to wait for the replacement, and to think twice about 'shopping local' in future!