UFH - Chipboard flooring above aluminium spreader plates

[TinyGillespie]

As part of a renovation project, we have had underfloor heating retrofitted downstairs in two rooms and a hallway.
Insulation has been added between the joists and then pipes (16mm I think) have been laid across aluminium spreader plates. Above this is 22mm chipboard flooring.
The rest of the downstairs extension has been fitted with underfloor heating pipes in screed. We have had a heatpump installed.

I have two questions:
1. We've noticed that the retrofitted rooms don't get particularly warm. Is this always going to be an issue with 22mm chipboard? Apparently the heat pump engineer specified to the builder to use a more thermally efficient thinner gauge board. I've only taken up a small piece of flooring to investigate as I don't want to damage the flooring unless I have to. Photo attached of the pipes under the floor - this section is close to where the floorboards meet the concrete. I hope this is why one of the pipes isn't sitting inside the spreader plate.
2. The chipboard flooring creaks quite badly. The builder has claimed this is due to expansion/contraction caused by the UFH. I suspect we are being fobbed off. I realise there might be a number of causes of this. On the face of it the boarding looks to have been laid well and glued where the tongue and groove sections meet. I wondered if it might be as simple as the wrong type of screws being used to screw the boards down? I've read various other threads which suggest using Spax or ScrewTite flooring screws to prevent squeaking.

 

[Why Not Indeed]

Did you see the boards before they went down? Are they routed, ie something like https://theufhgroup.co.uk/products/tekwarm-chipboard-ufh-board-2400mm-x-600mm ?

 

[robinbanks]

We've noticed that the retrofitted rooms don't get particularly warm

That's because alu spreader plates suck, I'm afraid! Worse, the plate you've pictured doesn't have the pipe clipped into it, you seem to have gaps in your plates and your pipe density is low. Adding a floor covering is going to make things worse too

You may have success turning the flow temp up but I have doubts..
Do you have any screed anywhere that needs to run at a lower temp? Does that manifold have something like a TMV?

 

[robinbanks]

We've noticed that the retrofitted rooms don't get particularly warm

That's because alu spreader plates suck, I'm afraid! Worse, the plate you've pictured doesn't have the pipe clipped into it, you seem to have gaps in your plates and your pipe density is low

You may have success turning the flow temp up but I have doubts..
Do you have any screed anywhere that needs to run at a lower temp? Does the manifold have something like a TMV?

If those screws pictured are what holds the floor, I wouldn't initially suspect them to be the source of the creaking because they're fully threaded. Creaks occur when flooring moves up and down smooth fixings (eg non-ring nails) fractionally.. but by all means see if fitting alternative screws helps. It could be that your existing screws aren't clamping the flooring tightly enough against the joist and it's the joist rubbing on the chipboard that makes the noise. It's more permanent, if you're brave, but glueing and screwing the board to the joist really reduces the chance of that occurring

 

[TinyGillespie]

Did you see the boards before they went down? Are they routed, ie something like https://theufhgroup.co.uk/products/tekwarm-chipboard-ufh-board-2400mm-x-600mm ?

I didn't, we were living elsewhere at this point. In fact I think this might have all been fitted during the week we were on holiday. The bit of board I removed isn't routed, and, I'm asssuming that as the spreader plates were used none of the other boards are routed.

Wouldn't it be a case of one or the other, as the pipes couldn't fit inside both the spreader plates and the routing board?

 

[TinyGillespie]

That's because alu spreader plates suck, I'm afraid! Worse, the plate you've pictured doesn't have the pipe clipped into it, you seem to have gaps in your plates and your pipe density is low

You may have success turning the flow temp up but I have doubts..
Do you have any screed anywhere that needs to run at a lower temp? Does the manifold have something like a TMV?

If those screws pictured are what holds the floor, I wouldn't initially suspect them to be the source of the creaking because they're fully threaded. Creaks occur when flooring moves up and down smooth fixings (eg non-ring nails) fractionally.. but by all means see if fitting alternative screws helps. It could be that your existing screws aren't clamping the flooring tightly enough against the joist and it's the joist rubbing on the chipboard that makes the noise. It's more permanent, if you're brave, but glueing and screwing the board to the joist really reduces the chance of that occurring

We've adjusted the flow pressure to the pipes (red ones) that go into these areas. (This is an old photo so doesn't show that this has been changed.)

It sounds like we need to focus on the pipe issue first and worry about the squeaking later. We're going to have to take the floorboards up to see exactly what we're dealing with.

 

[Madrab]

Who fitted the UFH? If it was the builder then there's the first mistake. Who fitting the P5 on top of it? Was that the builder again?

The UFH should not have been retrofitted under chipboard, the wood, especially P5 is an insulator and unless the UFH was specc'd high enough it would never heat up correctly. It should really have been a cementitious board like a NoMorePly TG4 or other structural cement board

If you are talking about squeaking when walking on the floor then that can be down to a couple of things. Incorrectly screwed or the T&G board joints are in the middle of joists and have not been glued correctly. UFH would only make the floor click as it expands not squeak. Sometime you can get away with WD'ing/floor oiling the joints of all things, as it lubricates the wood, BTBH that's just a fudge.

 

[TinyGillespie]

Who fitted the UFH? If it was the builder then there's the first mistake. Who fitting the P5 on top of it? Was that the builder again?

The UFH should not have been retrofitted under chipboard, the wood, especially P5 is an insulator and unless the UFH was specc'd high enough it would never heat up correctly. It should really have been a cementitious board like a NoMorePly TG4 or other structural cement board

If you are talking about squeaking when walking on the floor then that can be down to a couple of things. Incorrectly screwed or the T&G board joints are in the middle of joists and have not been glued correctly. UFH would only make the floor click as it expands not squeak. Sometime you can get away with WD'ing/floor oiling the joints of all things, as it lubricates the wood, BTBH that's just a fudge.

Thanks, that's useful to know, although obviously not what I wanted to hear.

The UFH in the main extension was fitted by a specialist company sorted by the builder. The retrofitted underfloor heating was fitted by the builder under instruction from the heat pump engineer. The heat pump engineer then connected everything up.

The builder was advised/told what flooring to fit over the UFH but appears to have ignored this. I realise now getting the builder to do this was a mistake, but, initially they appeared to be competent. At this point I'm trying to figure out what's the best course of action to take to rectify the problems.

 

[Madrab]

No doubt it isn't good news and everyone has to make a judgement call when it comes to these things. Most of the time it works out, sometimes it doesn't which in your case is unfortunate. I presume the pics above are from the retrofit and not the extension? Is the extension heating ok? What UFH system/covering is in there?

Primarily to give the system every chance of working properly, get rid of the chipboard flooring and replace with a material that is going to conduct heat properly. Structural cement board would be the best choice IMO. The alternative would have been an overlay board but it's a bit far down the line to consider that now.

No doubt the builders have used chipboard because that's been the easiest, quickest and cheapest option for them, I'd certainly be taking them to task if they haven't used what they were supposed to.

 

[TinyGillespie]

No doubt it isn't good news and everyone has to make a judgement call when it comes to these things. Most of the time it works out, sometimes it doesn't which in your case is unfortunate. I presume the pics above are from the retrofit and not the extension? Is the extension heating ok? What UFH system/covering is in there?

Primarily to give the system every chance of working properly, get rid of the chipboard flooring and replace with a material that is going to conduct heat properly. Structural cement board would be the best choice IMO. The alternative would have been an overlay board but it's a bit far down the line to consider that now.

No doubt the builders have used chipboard because that's been the easiest, quickest and cheapest option for them, I'd certainly be taking them to task if they haven't used what they were supposed to.

Yes, it's just the retrofitted area that's the problem. The underfloor heating in the extension is working well, this had screed poured over it.

Absolutely we'll be taking this up with the builders, I'm trying to establish all the facts before I deal with them.

 

[Madrab]

Yes, it's just the retrofitted area that's the problem. The underfloor heating in the extension is working well, this had screed poured over it.

Don't want to throw more water on the fire but..... given the manifold doesn't have actuators, each area won't be zoned? Is there a separate pump and thermo mixer for the manifold too, can't see them in the pic. Do you have any other emitters, rads etc?

As the sections aren't zoned then the other concern I would have is that the screeded section would normally be run differently than the retrofitted spreader plated area. One is a large thermal mass that should really be kept at a constant temp to work efficiently, the other is more reactionary as there is no thermal mass and is normally switched on when needed. Both would also usually be run at different temps.

Who designed the UFH setups?

 

[TinyGillespie]

The UFH setup was designed by the heat pump engineer. He's coming back to discuss the options with us. Apparently he did discuss using the cementitious board with the builders, which they've not done.

On the ground floor we only have one zone.