Chipboard As A Subfloor

Good afternoon

I came across a job today where the lines of the plywood was visible through some LVT. The foor make up was piped underfloor heating, then chipboard and 6mm ply stapled to the chipboard.The floor was fine for 6 or 7 month, the UFH kicks in and all the borders of the ply are now visible. I am presuming that stapling 6mm ply to chipboards is maybe part of the issue here?

 

Let's hope none of the staples have shot through to a pipe, seen that a few times. I've ripped out old ply that had been down a few year and disrupted the nail that had been stuck through a pipe just enough to penetrate it. Soon as that came out there was water weeping through.

So when you say visible through the lvt, you saying the ply looks like it's swelled? Or feels like it's popped from its fixings?

 

The ply has shrunk as we exposed some of the LVT, on one join the ply had shrunk and either the jointing/compound latex had sunk so the LVT also sunk. No cracks in the join it all seemed sound. Surely though staples into chipboard with UFH are not the best fixing method would you not use screws

 

In answer to your question has it popped I would say more like shrunk

 

It’s not a case of trying to blame someone I just want to get to the bottom of the problem as the client is someone we know of and the fitter is being very vague in what information he is passing over so just still trying to get the full account of what has gone there. All I know at the moment that the ply has been fixed to chipboard with staples so taking that into account and no issues in the summer months then come winter with the under floor heating running these lines appear...

 

Maybe the ply was fitted poorly in the first place and now the heat is underneath is enough to soften the planks and draw more attention to any gaps in the prep. No mention of feather either!

 

I would have used coil nails the least but screws if I had my labourer with me...

 

[Hufffffff] *cool

 

Was the plywood acclimisted to the room.

Yeah for me. Nail the ply then a fibre screed.

 

....never mind not had many installs where ive had to ply over ufh but recently after switching to uzins feather ive used it over the last one I did.

 

What glue would you use on UFH.

Fball say F46 PS over HT

 

If it’s taken that long for the ply to shrink it sounds like the ufh is on too high and dried out the ply. Maybe the plywood has taken on moisture at some point and swollen? Staples are not great but if ply wants to shrink no fixings will stop that.


Sent from my iPhone using Tapatalk

 

Spoke with Ardex rep Before Christmas and he said feather was fine on ufh ??

 

Interesting , what’s your recommendation ?