Posted by: @maximumdo

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The current build-up is 16mm pipe clipped to PIR insulation between timber joists, with 22mm chipboard above. There is effectively an air gap between the pipework and the floor deck, which seems to be significantly limiting heat transfer.

Ok, I'm not an expert in underfloor heating and I'm not from the UK, so I can't help you there, but every time I read something like this I wonder who the heck comes up with building heating systems like that. The air gap is a problem. The chip board is a problem as well as it's essentially an insulator for heat transfer as well. So if I understand correctly you have heating pipes -> air gap -> chip board... yeah, that's never going to work and never should have been installed as such. It has to be the least efficient way to set up underfloor heating. There is no bridge to carry the heat from the pipe to the floorboard in the first place. If you then add wood floor on top, it only gets worse. Air is an insulator. You are essentially trying to heat the room using a low-temperature radiator inside a sealed wooden box.

The way you could apparently fix this (again, I'm not an expert, I had to Google this installation method which apparently is done in some places):

- Fill the air gap around the pipes with a biscuit screed (a sand/cement mix) or specialized conductive granules. This creates a solid mass that touches both the pipe and the underside of the chipboard, eliminating the air gap.

Personally: I would check if your floor is structurally sound enough to just get rid of the chipboard, and pour screed to the level of where the chip board is now. Place your wood floor over that with an appropriate underlay that minimizes insulation. The screed will act as thermal mass, which has lots of additional benefits (much more gradual temperature changes, rooms not cooling down fast, etc.)

Again, not an expert, so don't take what I wrote as advice, but as someone living in a cold climate, it pains me to see how bad heating systems are engineered over there...

@upnorthandpersonal I agree with what you are saying. I am looking for a company to help me fix it. 

I have been advised that biscuit screed would increase thermal mass but not output.

I’m not an expert and I am looking for one. Thanks 

Posted by: @maximumdo

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Hi everyone,

I am looking for an experienced underfloor heating specialist who can help us resolve a significant issue.

As part of a full house renovation, I spent considerable time researching before appointing an installer to supply and fit our heat pump and UFH system. There was a long gap between design and installation, and the work was completed just before Christmas during what was already a very stressful period for us. We were not living in the property at the time, and I regret not scrutinising the finer details more closely.

In short, the UFH has not been installed in line with the design intent, and there is insufficient pipe coverage for the downstairs to reach a comfortable temperature.

The current build-up is 16mm pipe clipped to PIR insulation between timber joists, with 22mm chipboard above. There is effectively an air gap between the pipework and the floor deck, which seems to be significantly limiting heat transfer. Upstairs radiators are performing as expected, so the issue is isolated to the UFH.

The installer has acknowledged that the system is not right, but we are not being presented with a technically clear resolution.  We are now at the stage where we simply need this fixed properly. We have engineered oak flooring ready to be laid and decorating on hold. The uncertainty is taking its toll.

Suggestions from a couple of people I have spoken to so far have ranged from adding screed and cement boards, to removing the chipboard and relaying with routed/grooved boards. We are constrained by finished floor heights at the bifold doors and by pipework that runs through a now-tiled utility floor.

At this point, we are prepared to incur additional cost if necessary, but we need a competent specialist to assess the situation, review the design versus installation, and provide a definitive solution.

If your company has the expertise and capacity to assist, I would be extremely grateful to hear from you. We are based in Farnham, Surrey.

Thank you for taking the time to read this.

You must heat a mass when using UFH, the only alternative I can think of if you do not use a mass like screed is to use deflector plates that clip the UFH pipework to the chip board. TBH the best overlay to use is overlay boards so they are using the boards as the deflector.

https://www.theunderfloorheatingcompany.co.uk/product/aluminium-spreader-plate-2-grooves-200mm-centres/?srsltid=AfmBOop2YUo8WsnnZbVXetsvaDJlV1c0_NVbJi7R_u3IPClmkoFCDGO5

Posted by: @ashp-bobba

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Posted by: @maximumdo

↑

Hi everyone,

I am looking for an experienced underfloor heating specialist who can help us resolve a significant issue.

As part of a full house renovation, I spent considerable time researching before appointing an installer to supply and fit our heat pump and UFH system. There was a long gap between design and installation, and the work was completed just before Christmas during what was already a very stressful period for us. We were not living in the property at the time, and I regret not scrutinising the finer details more closely.

In short, the UFH has not been installed in line with the design intent, and there is insufficient pipe coverage for the downstairs to reach a comfortable temperature.

The current build-up is 16mm pipe clipped to PIR insulation between timber joists, with 22mm chipboard above. There is effectively an air gap between the pipework and the floor deck, which seems to be significantly limiting heat transfer. Upstairs radiators are performing as expected, so the issue is isolated to the UFH.

The installer has acknowledged that the system is not right, but we are not being presented with a technically clear resolution.  We are now at the stage where we simply need this fixed properly. We have engineered oak flooring ready to be laid and decorating on hold. The uncertainty is taking its toll.

Suggestions from a couple of people I have spoken to so far have ranged from adding screed and cement boards, to removing the chipboard and relaying with routed/grooved boards. We are constrained by finished floor heights at the bifold doors and by pipework that runs through a now-tiled utility floor.

At this point, we are prepared to incur additional cost if necessary, but we need a competent specialist to assess the situation, review the design versus installation, and provide a definitive solution.

If your company has the expertise and capacity to assist, I would be extremely grateful to hear from you. We are based in Farnham, Surrey.

Thank you for taking the time to read this.

You must heat a mass when using UFH, the only alternative I can think of if you do not use a mass like screed is to use deflector plates that clip the UFH pipework to the chip board. TBH the best overlay to use is overlay boards so they are using the boards as the deflector.

 

https://www.theunderfloorheatingcompany.co.uk/product/aluminium-spreader-plate-2-grooves-200mm-centres/?srsltid=AfmBOop2YUo8WsnnZbVXetsvaDJlV1c0_NVbJi7R_u3IPClmkoFCDGO5

 

To add, you will probably find the UFH brand they used sells a spreader plate application to suit the pipe, if not I think as standard they take a 16mm pipe. we have these screwed to the bottom of a mezz floor we did last year and they heat the floor above through 38mm load bearing chip boarding.

Posted by: @ashp-bobba

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Posted by: @maximumdo

↑

You must heat a mass when using UFH, the only alternative I can think of if you do not use a mass like screed is to use deflector plates that clip the UFH pipework to the chip board. TBH the best overlay to use is overlay boards so they are using the boards as the deflector.

 

https://www.theunderfloorheatingcompany.co.uk/product/aluminium-spreader-plate-2-grooves-200mm-centres/?srsltid=AfmBOop2YUo8WsnnZbVXetsvaDJlV1c0_NVbJi7R_u3IPClmkoFCDGO5

 

I am getting conflicting advise. Some say a biscuit screed and cement boards. Some say that won’t help and I need more pipes. TBH a biscuit screed and cement boards is our easiest option.

We have a height issue, so overlay boards can’t be used.

Posted by: @ashp-bobba

↑

Posted by: @ashp-bobba

↑

Posted by: @maximumdo

↑

Hi everyone,

I am looking for an experienced underfloor heating specialist who can help us resolve a significant issue.

As part of a full house renovation, I spent considerable time researching before appointing an installer to supply and fit our heat pump and UFH system. There was a long gap between design and installation, and the work was completed just before Christmas during what was already a very stressful period for us. We were not living in the property at the time, and I regret not scrutinising the finer details more closely.

In short, the UFH has not been installed in line with the design intent, and there is insufficient pipe coverage for the downstairs to reach a comfortable temperature.

The current build-up is 16mm pipe clipped to PIR insulation between timber joists, with 22mm chipboard above. There is effectively an air gap between the pipework and the floor deck, which seems to be significantly limiting heat transfer. Upstairs radiators are performing as expected, so the issue is isolated to the UFH.

The installer has acknowledged that the system is not right, but we are not being presented with a technically clear resolution.  We are now at the stage where we simply need this fixed properly. We have engineered oak flooring ready to be laid and decorating on hold. The uncertainty is taking its toll.

Suggestions from a couple of people I have spoken to so far have ranged from adding screed and cement boards, to removing the chipboard and relaying with routed/grooved boards. We are constrained by finished floor heights at the bifold doors and by pipework that runs through a now-tiled utility floor.

At this point, we are prepared to incur additional cost if necessary, but we need a competent specialist to assess the situation, review the design versus installation, and provide a definitive solution.

If your company has the expertise and capacity to assist, I would be extremely grateful to hear from you. We are based in Farnham, Surrey.

Thank you for taking the time to read this.

You must heat a mass when using UFH, the only alternative I can think of if you do not use a mass like screed is to use deflector plates that clip the UFH pipework to the chip board. TBH the best overlay to use is overlay boards so they are using the boards as the deflector.

 

https://www.theunderfloorheatingcompany.co.uk/product/aluminium-spreader-plate-2-grooves-200mm-centres/?srsltid=AfmBOop2YUo8WsnnZbVXetsvaDJlV1c0_NVbJi7R_u3IPClmkoFCDGO5

 

To add, you will probably find the UFH brand they used sells a spreader plate application to suit the pipe, if not I think as standard they take a 16mm pipe. we have these screwed to the bottom of a mezz floor we did last year and they heat the floor above through 38mm load bearing chip boarding.

 

 

Our house was built in 1930s with 300mm joists. Are there spreader plates that will fit this? I can’t seem to find them. 

@maximumdo 

this one has 200mm centres so you could trim the plate to 70mm each side (70+200+70= 340mm) of the pipe so they overlap by 20mm 

https://www.theunderfloorheatingstore.com/products/prowarm-underfloor-heating-spreader-plates?variant=49500258468121&gclsrc=aw.ds&utm_term=&utm_campaign=PMAX+-+TUFHS+-+Insulation+Boards&utm_source=adwords&utm_medium=ppc&hsa_acc=6400250539&hsa_cam=20546130927&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1&gad_campaignid=20546127591&gbraid=0AAAAAD_LkMvJdY94STqS4CjtNW1HbCWYP&gclid=CjwKCAiAwNDMBhBfEiwAd7ti1GSK-gsqzrRysgrDslizidXOZBY81Db5n0BftI2Y5LjYDVtqZIAXlxoCq7wQAvD_BwE

to get 3 pipes in you could use this one and either trim 20mm edges and jam the pipes against the side of the beams or place a small crease down the middle and pinch 20mm of the metal together and then fold it over to keep it tight reducing the gap of one of the pipe centres, this would take someone that kind of knew what they are doing and also they are not expensive so you could practice, another way if you need 3 pipes is cut down one section between 2 of the pipes, overlap the metals and rivet back together effectively reducing the centres if 2 of the pipes to 110, so you would have centres 110 and 150 = 260+ 40mm each side total 340 plate again.

https://underfloorheating-direct.com/products/aluminium-spreader-plate-390mm-x-1000mm-150mm-centres?variant=47130651230511&country=GB&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&utm_term=&utm_campaign=SHOPPING+%7C+Brand+%7C+UFHD&utm_source=adwords&utm_medium=ppc&hsa_acc=5268660065&hsa_cam=23455303197&hsa_grp=194699491194&hsa_ad=792716830968&hsa_src=g&hsa_tgt=pla-826413260061&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1&gad_campaignid=23455303197&gbraid=0AAAAADeqQ9k6Nm44xqJRYPjsfTKf5LdyY&gclid=CjwKCAiAwNDMBhBfEiwAd7ti1DrNxa6lLLXaJXGlMDuxuxm49puSrM_pTZULTTPUnOWfE0Bk1lgrIxoCijkQAvD_BwE

These deflector plates are very soft, you can cut them with sharp taylor scissors, sheers or cheep drill nibler.

I even found that for you 🙂

as you can imagine I am always modifying everything, 36 years of getting round stuff I suppose, best of luck...

https://www.amazon.co.uk/s?k=sheet+metal+nibler&i=diy&crid=2ABVHIW8JYBRT&sprefix=sheet+metal+nibler%2Cdiy%2C108&ref=nb_sb_noss_2

Just one more thing to add, the best UFH is thick screed, next is overlay and next is deflector plates, my advice is if they are looking to give you 55w/2m and the design is 2 pipes / lane lets call it, i would place extra while you have the floor up as the deflectors although a good solution and helps you to connect to the mass of the chip board its a weaker connection so more contact and pipes will help.  

It would also help to insulate under the floor not to loose the heat down and the deflectors will emit in all directions (although heat rises) but it will help

Thank you for the information and advise. It is good to know something can be done.

The floor is insulated between the joists with 75mm PIR and is taped too. The current piping is clipped to that.

I’m looking for a company that will advise, quote and install the remedials as we’re not experts in the slightest. 

@maximumdo Great, good luck with the quotations and getting the works done.