Sagging chipboard floor

[ChocolateFrog]

Redoing the kitchen. I knew the floor wasn't perfect but took the first floor covering up to be met with this.



I assume that was a desperate attempt to stop them rocking, it didn't work, obviously.

Got the tiles up.



Adhesive is welded to the floor but that's not the main issue.

Probably the worst of it.



They also flex underfoot. Before I started I'd assumed I'd need to overboard with ply but now I'm thinking that will be a bit pointless and the whole thing needs ripping up and starting again.

It seems the moisture in the adhesive has done for them.

Guess I just want confirmation that starting again is the only real course of action.

[Little Lofty]

Probably used standard rather than moisture resistant, I would start again.

[Drumroll]

Would definitely completely redo that floor. Nothing is going to get that floor back to anything that will be safe,

[wolfracesonic]

That doesn’t even look like tongue & grooved chipboard, it does look fked though, so new boards required. Look for P5 tongue & grooved chipboard, comes in 18mm or 22mm thickness, the manufacturers website will tell you what thickness you need for your particular joist centres.

[ChocolateFrog]

Got the new floor in today. The stuff that was in already was the thicker version. Thinking about it when the house was built in 2003 there was a small fire started by vandalism. We're betting that the floor was never replaced after the fire service had done their thing.

New one feels so much better and

[Ryyy]

What centres are your joists? Looks far too big for the thickness of the previous floor and what was it anyway? Looks like 12mm chipboard

[ChocolateFrog]

Ryyy said:

What centres are your joists? Looks far too big for the thickness of the previous floor and what was it anyway? Looks like 12mm chipboard

23mm chipboard and 600mm centres. Still going to bond someply over the top as I'd already bought it as that was the plan initially before I actually saw the state of it.

[Ryyy]

23mm is the new stuff yeah? What thickness was the old? If it was 12 mm that's far thin for 600 centres,no wonder it sagged.i wouldn't even use it at 400 centres tbf.

[TA14]

That Batstrap is interesting. How is it attached to the joists. No noggins; is it supposed to be attached to the flooring somehow?

[ChocolateFrog]

Ryyy said:

23mm is the new stuff yeah? What thickness was the old? If it was 12 mm that's far thin for 600 centres,no wonder it sagged.i wouldn't even use it at 400 centres tbf.

The old stuff was 23 too.

[ChocolateFrog]

TA14 said:

That Batstrap is interesting. How is it attached to the joists. No noggins; is it supposed to be attached to the flooring somehow?

That flummoxed us too.

Left it as is. House hasn't fallen down, yet. There's another house on the other side of that wall.

[ChocolateFrog]

Overboarded with ply, glued and screwed it down yesterday.

Feels a lot more solid underfoot now, 99% of creaks have gone. Even the new floor flexed slightly with 100+kg stood between the joists.

Not sure if it's a done thing but laying 2 layers of chipboard the second perpendicular to the first would probably be a decent solution for not much money.

[Panamax]

Whose ceiling is that underneath your kitchen floor? Shouldn't there be some soundproofing in there?