Options for fixing this uneven subfloor?

[boilerhater]

Hi - this video illustrates my problem pretty well: http://sendvid.com/1qt1mx0w Also attached two pictures to thread.

Basically my floor is buggered at the crossover between my living room & hall. My living room subfloor is the original Victorian floorboards, while in the hallway it's a ply subfloor. (The ply and the top layer floorboards were installed two years ago - not yet sure if the latter is floating, nailed or glued.)

What are my options for getting this fixed? I don't care about sloping as my hallway joists slope inwards anyway (should have had them levelled when I had the chance). But I can't live with this movement & squeaking anymore!

Will lifting the boards be difficult if they're nailed / glued? How about drilling through the affected board and either injecting levelling compound or clamping it down somehow?

Not gonna attempt this myself but want to know my options before getting a professional round

Cheers for any help

 

[Deleted member 174758]

How about drilling through the affected board and either injecting levelling compound or clamping it down somehow?

Presumably you don't know what is beneath the floor. Is it porous? Are there holes in it? Or big gaps/cracks? In other words how can anyone guarantee that any compound you inject won't just drain away? Secondly, how does anyone actually gauge how much material they should inject? And finally how solid is that sub-floor and what is causing this gapping? I'm sort of playing the Devil's advocate to try and show the problems that there might well be in injecting anything beneath a floor such as this. On top of that there's the issue of anything you inject almost certainly making it very difficult to remove that laminate in the future (because injected compounds will necessarilly be "sticky". IMHO it's only when you get into the sub floor that you can really find out what's gone wrong and undertake appropriate repairs

Personally, I'd want to lift out that section of the laminate and maybe a bit back from that, then sort-out the problems with the sub f oor for once and for all before replacing the laminate. I recognise that it might be necessary to introduce some form of hardwood threshold to achieve this as getting laminate out from the middle of a floor then back in can be problematic to say the least.

 

[boilerhater]

Hi Jobandknock thanks for replying! I just looked over my quote and re the hallway subfloor it's either 18mm chipboard or 22mm plywood with timber support - I think I went with chipboard but not certain to be honest. It was put in two years ago & no holes, but I can't say whether porous or not. So I see how injecting is risky.

It's not laminate top floor btw - it's solid tongue & groove hardwood about 3cm thick. I'm presuming the cause of the gapping is the transition from the original floorboard subfloor (in living room) and the new ply/chip subfloor (in hallway). I.E. uneven heights that weren't levelled off neatly. But for all I know it could be something else - maybe not allowing enough of a gap under the skirting so the wood "tents" upwards?

I agree getting under there is the only way to tackle this properly now. I'm gonna have to find out if the boards are floating / glued / secret nailed. (I don't suppose you can guess based on the movement?)

If glued or nailed, will it be really time-consuming & annoying lifting the boards without damaging them? And will I have to lift up virtually the whole hallway or will removing nearby skirting possibly offer quicker access?

(Appreciate I'm asking hypothetical questions here!)

 

[dazlight]

No breaks in the doorways so the wood has expanded to much and hit a wall on one end I’d say. Need skirts off and cut new expansion.
If more heat in a room then a hallway it can cause different rates of expansion.

 

[boilerhater]

Hi Daz - I did wonder if that was a possibility but thought wonky subfloor more likely. In this pic the living room rad is always on while hall one always off. Maybe that caused it? Can't remember if it was like this two years ago when I did renovation.

Would lifting the skirting on the far wall in the pic allow someone to trim the board edges without tearing up everything? (I guess that'd only work if free floating?)

 

[dazlight]

I’d say the heat has caused it. Any direct sunlight on the living room?

I did a repair in a kitchen the other year. Looked the same as your video. The floor was floated and all tight on the kitchen side. I had to trim all under there and take 10mm off the main wall. Floor went flat straight away.

 

[boilerhater]

No direct sunlight anywhere in my gloomy Edinburgh flat But I do crank up that rad quite a lot in winter.

If it's floating I'll breathe a sigh of relief for sure and the fix you described doesn't sound as bad as I'd imagined. Just to check - what do you mean trim underneath? I understand cutting 10mm off at the skirting but not sure what the trimming means?

Either way this would be a best case scenario for me! Fingers crossed

 

[boilerhater]

Just a thought... Would a T-bar threshold be an alternative, albeit less aesthetically pleasing fix? (Not sure if the subfloor differences make this problematic)

 

[dazlight]

Yeah put one of them in the doorway as it will help with expansion.
Trimming means cutting 10mm off the edges mate in my mad terms.

 

[boilerhater]

Hi - one year on & locked in the house I finally got round to attempting this fix... I removed the skirting and fireplace trim at far end of living room and added a nice big expansion gap. Sure enough my contractor hadn't bothered doing that, and in fact it had started to cause cupping in the boards in the living room (as well as cracking my hearth).

The impact on the living room floorboards has been quite dramatic - clearly the pressure is released now.

However, these troublesome boards at the threshold are only half better - and that may just be because of the season. Bottom line they're still not sitting on the subfloor neatly, so they're still moving / squeaking when stepped on (as in the original video above).

I can see three options for a solution so was hoping someone could steer me in the right direction:

1. Install T-bar at the threshold. This was originally suggested by dazlight but the problem is that it would need to go where the black line is in the pic below. So it'd help with expansion - which hopefully is less of an issue now - but it won't change the fact that the boards aren't sitting flat on the subfloor. So the movement would continue.

2. Drive trim screws through the boards to fix them to the plywood subfloor, which should in turn be fixed to the joists (pretty sure it was). It's the edges of board B in the pic that sink when stepped on, so I'm guessing screws in the four places marked with tape would clamp it down nicely? I know there'd be some aesthetic damage, but a little bit of filler wouldn't bother me as much as this movement. (Boards A & C shouldn't need screws - I think - because they only lift at their respective edges with B, not anywhere else.)

3. Get a professional to cut out the boards, level the subfloor, and put them back down. They're tongue and groove boards so this isn't something I'd attempt myself. (I had been told by someone before that the whole floor might need to come up, but looking on YouTube it appears even tongue & groove can be removed in isolation if you know what you're doing?)

I recognise that (3) is probably the best option, but practically speaking it'll be difficult to find a tradesman who wants the hassle of this job. My gut tells me (2) is my best bet... I just don't want to mash up my floorboards until I'm more confident!

Any advice gratefully received

EDIT as per the second pic, a Tbar definitely isn't an option. It'd be wonky as hell thanks to my gloriously uneven Victorian archetrave...

 

[HERTS P&D]

Most important, what are you wearing on your feet?

Andy

 

[boilerhater]

Nice toasty slippers It gets cold here!