swelliott Posted February 19, 2021 Share Posted February 19, 2021 Hi, I am going to be purchasing a Profix low profile UFH system from The Floor Heating Warehouse. I have been told that the castellated trays do not have double sided adhesive on the backs (unlike a lot of other companies’ trays) and that they need to be screwed down using at least five screws per tray. The trouble is that the flat I am laying it in is an old 1950s building and there is at least 1 pipe (which I know of) buried in the floor about 20-30mm from the surface. As such, I don’t really want to run the risk of putting a screw straight through a water pipe and have therefore thought about sticking the trays down with something like No Nonsense contact spray adhesive. Has anybody else done this or got other ideas for keeping the trays stuck to the floor whilst I pour the liquid screed on it? Alternatively, will the no-nonsense spray adhesive service in keeping the trays in situ? Many thanks in advance for your input. Link to comment Share on other sites More sharing options...
Temp Posted February 19, 2021 Share Posted February 19, 2021 Is there enough insulation in the floor for UFH? Link to comment Share on other sites More sharing options...
OldSpot Posted February 19, 2021 Share Posted February 19, 2021 (edited) 2 hours ago, swelliott said: I have been told that the castellated trays do not have double sided adhesive on the backs (unlike a lot of other companies’ trays) and that they need to be screwed down using at least five screws per tray. Really? According to Profix they do! You could probably use 5 minute PU adhesive like Lumberjack or Soudal Edited February 19, 2021 by OldSpot Link to comment Share on other sites More sharing options...
swelliott Posted February 19, 2021 Author Share Posted February 19, 2021 Thanks for the replies Temp and Oldspot. Temp - the existing floor is the original screed floor that was laid down when the building was built in the 1950s. Whether there is insulation underneath the top level of the screen or not, I don’t know. However I am governed by what I can put down by the lake at the front door which is approximately 40 mm high And I still have to get tiles and tile adhesive on top of the screed yet. oldspot- Thanks for pointing this out. It’s the first time I’ve seen that. If you have a look on the floor heating warehouse website it shows a YouTube video with them screwing down the drains. I have emailed Profix to confirm which is the correct procedure. Thanks for the adhesive recommendations. Link to comment Share on other sites More sharing options...
Onoff Posted February 19, 2021 Share Posted February 19, 2021 ? I used the red Polypipe trays. They just clip together. Any overlapping joints I was concerned about just went over with duct tape. Link to comment Share on other sites More sharing options...
OldSpot Posted February 19, 2021 Share Posted February 19, 2021 (edited) Looking at the Profix website it looks like the standard panels have an adhesive backing but the panels with a XPS insulation bonded to them do not. Profix suggest these have to be screwed down in their installation video. Edited February 19, 2021 by OldSpot Link to comment Share on other sites More sharing options...
Temp Posted February 19, 2021 Share Posted February 19, 2021 3 hours ago, swelliott said: Temp - the existing floor is the original screed floor that was laid down when the building was built in the 1950s. Whether there is insulation underneath the top level of the screen or not, I don’t know. However I am governed by what I can put down by the lake at the front door which is approximately 40 mm high And I still have to get tiles and tile adhesive on top of the screed yet. Im not sure I would install UFH without finding out. We have 80mm of PIR in our floor between battens and wish we had more. Link to comment Share on other sites More sharing options...
swelliott Posted February 19, 2021 Author Share Posted February 19, 2021 4 hours ago, OldSpot said: Looking at the Profix website it looks like the standard panels have an adhesive backing but the panels with a XPS insulation bonded to them do not. Profix suggest these have to be screwed down in their installation video. Thanks Oldspot. I called Profix today and they said the reason they state on their website that the low profile trays can be stuck down with self adhesive backing is because they are launching self adhesive backed panels in April. However, as they are not ready for sale yet, the current trays still need to be screwed down. Link to comment Share on other sites More sharing options...
swelliott Posted February 19, 2021 Author Share Posted February 19, 2021 3 hours ago, Temp said: Im not sure I would install UFH without finding out. We have 80mm of PIR in our floor between battens and wish we had more. Thanks for the input Temp. I may be wrong so please correct me if so, but I thought that these low profile systems were meant to overcome the need for lots of insulation underneath the UFH because, as with retro fitting in old houses, installations have little depth to play with (without digging up the existing substrate), and secondly, the pipes are a lot closer to the surface so more heat is felt in the room. Link to comment Share on other sites More sharing options...
Temp Posted February 20, 2021 Share Posted February 20, 2021 They can't do the impossible. Link to comment Share on other sites More sharing options...
scottishjohn Posted February 21, 2021 Share Posted February 21, 2021 will be a failure with NO insulation below -do not fit with on insulation layer ones with no insulation assuming you are using an insulation layer then fitting panels OR you have a full concrete floor with insulation uderneath the slab and then creed on top of your panels and pipes Link to comment Share on other sites More sharing options...
Onoff Posted February 21, 2021 Share Posted February 21, 2021 On 19/02/2021 at 20:42, swelliott said: Thanks for the input Temp. I may be wrong so please correct me if so, but I thought that these low profile systems were meant to overcome the need for lots of insulation underneath the UFH because, as with retro fitting in old houses, installations have little depth to play with (without digging up the existing substrate), and secondly, the pipes are a lot closer to the surface so more heat is felt in the room. A member here has a super insulated house with 300mm of polystyrene under his heated concrete floor slab (100mm thick from memory). He's calculated he still loses 8% down through the floor. (Don't get me wrong, any insulation is better than nothing). Link to comment Share on other sites More sharing options...
PeterW Posted February 21, 2021 Share Posted February 21, 2021 On 19/02/2021 at 09:34, Temp said: Is there enough insulation in the floor for UFH? None by the sounds of it ... On 19/02/2021 at 20:42, swelliott said: Thanks for the input Temp. I may be wrong so please correct me if so, but I thought that these low profile systems were meant to overcome the need for lots of insulation underneath the UFH because, as with retro fitting in old houses, installations have little depth to play with (without digging up the existing substrate), and secondly, the pipes are a lot closer to the surface so more heat is felt in the room. Far from it - you will just be heating a concrete slab and the ground underneath. With no insulation - 1950’s they didn’t use any - you will have basically a massive heat sink under the floor. What heat source are you using for this ..? Also, the tray systems work better with screed - you sound like you want to tile so if you have 40mm to play with and desperately want to use UFH, you need to go with one of the insulation panel systems which will allow direct tiling and allow for this at the door. That would probably limit you to 25mm insulation level max. You need to look at this sort of product. https://www.wundatrade.co.uk/shop/home/quick-shop/wundatherm-quick-shop/boards-quickshop/underfloor-heating-board-wundatherm-ultimate/ Link to comment Share on other sites More sharing options...
swelliott Posted February 22, 2021 Author Share Posted February 22, 2021 Thanks to everyone for your comments and thoughts. The flat I am renovating will be to flip and sell ,and although I am not the type of person to cut corners, pulling up the current floor in order to get more insulation down under the UFH will cost a small fortune. Furthermore, my preferred heating system in this type of flat would have been traditional radiators. However, the floor is solid concrete throughout and so is the ceiling, which again would ensure that the running of pipework to all the radiators would be an an absolute nightmare in chasing out. Because I am governed by the step at the front door of only 40mm, with the low profile system and screed being 20mm, adhesive and tiles being another 13mm, that only leave me 7mm to play with. So after reading everyone's comments, I will go with the low profile castellated trays that are already backed with 6mm insulation. I'm sure there will be people out there who say this ins't nearly enough but apart from pulling up the existing floor, I can't see that there is anything else I can do. Thanks again. Link to comment Share on other sites More sharing options...
Mr Punter Posted February 22, 2021 Share Posted February 22, 2021 Your supplier is badly reviewed. If your flat is on the ground floor, most of the heat will go straight into the ground. There is an aim around the world to reduce C02 emissions and your proposal is doing the opposite, by heating up a large conductive area in direct contact with the ground. I appreciate there are no simple solutions for this but 6mm insulation is not going to do much. At least go for the overlay boards suggested by @PeterW. Most people here doing new build would suggest at least 100mm of high performance insulation for UFH. Can you take a bit off the bottom of the doors? Link to comment Share on other sites More sharing options...
Big Jimbo Posted February 22, 2021 Share Posted February 22, 2021 The poster is only looking to do up, and flip the flat. The lack of heating will be a problem for the purchaser. Heating on 24 hours a day, and still freezing. One of the reasons i have never bought a property that has been done up. Imagine paying top price for the flat, because it looks the biz, only to find the heating costs a fortune to run, and it's shite. 1 Link to comment Share on other sites More sharing options...
TonyT Posted February 22, 2021 Share Posted February 22, 2021 (edited) It’s not the first flat with concrete floors and ceiling to get rewired and new heating system. Post a layout drawings of the flat, showing boiler positions, cupboards etc you can make box skirtings to hide pipes, put radiators back to back etc UFH will be pants in this flat Edited February 22, 2021 by TonyT 1 Link to comment Share on other sites More sharing options...
swelliott Posted February 22, 2021 Author Share Posted February 22, 2021 6 hours ago, Mr Punter said: Your supplier is badly reviewed. If your flat is on the ground floor, most of the heat will go straight into the ground. There is an aim around the world to reduce C02 emissions and your proposal is doing the opposite, by heating up a large conductive area in direct contact with the ground. I appreciate there are no simple solutions for this but 6mm insulation is not going to do much. At least go for the overlay boards suggested by @PeterW. Most people here doing new build would suggest at least 100mm of high performance insulation for UFH. Can you take a bit off the bottom of the doors? Thanks for your post Mr Punter. Can you tell me where you've seen the bad reviews? I did look for online reviews but could only find 1 website, Trustpilot, that reviews The Floor Heating Warehouse, and that had mixed reviews. I have looked into buying the Uponor Minitec system (https://www.uponor.co.uk/products/underfloor-heating/minitec). Have you had any experience of them? I have looked into overlay boards, but they all seem to say they are for tiling over or laying wood on. I will have a mixture of carpet, wood and tiles in the various rooms of the flat. The Wundatherm panels that PeterW refers to seems to be the same as the insulated panel that I am getting on the castellated trays, just not as thick as I am governed by the front door step. Although those panels can be up to 25mm thick (https://www.thefloorheatingwarehouse.co.uk/acatalog/Profix-Insulation--PPInsul.html#SID=556). I would love to have 100mm of insulation under the UFH but the current design of the flat means I can't. I could take some off all the doors, but not too much otherwise I would be left with a big step into the flat from an internal hallway which would look rubbish. I would like to say that even though I'm a developer and renovating the flat to sell, I'd like to think that I am conscientious and do think about the next owner despite what some might say. I know there are developers out there who don't care about the onward purchase, but I do. If I didn't, I wouldn't have come to this site for advice. Thanks Mr. Punter. Link to comment Share on other sites More sharing options...
swelliott Posted February 22, 2021 Author Share Posted February 22, 2021 On 21/02/2021 at 10:19, PeterW said: None by the sounds of it ... Far from it - you will just be heating a concrete slab and the ground underneath. With no insulation - 1950’s they didn’t use any - you will have basically a massive heat sink under the floor. What heat source are you using for this ..? Also, the tray systems work better with screed - you sound like you want to tile so if you have 40mm to play with and desperately want to use UFH, you need to go with one of the insulation panel systems which will allow direct tiling and allow for this at the door. That would probably limit you to 25mm insulation level max. You need to look at this sort of product. https://www.wundatrade.co.uk/shop/home/quick-shop/wundatherm-quick-shop/boards-quickshop/underfloor-heating-board-wundatherm-ultimate/ Thanks for the constructive comments PeterW. I've chosen to go with the tray systems as they seem to offer a low profile option, obviously something I need because of the 40mm max. depth issue. I will be putting liquid screed on top and I've been told 20mm is recommended which is just over the top of the trays. I will be tiling the kitchen, hallway and bathroom, but the lounge will have engineered wood on top and the 2 bedrooms will be carpeted. The Wundatherm panels that you refer to seems to be sort of the same as the insulated panel that I am getting on the castellated trays, just not as thick as I am governed by the front door step, although they do come in up to 25mm thick (https://www.thefloorheatingwarehouse.co.uk/acatalog/Profix-Insulation--PPInsul.html#SID=556). Link to comment Share on other sites More sharing options...
Mr Punter Posted February 22, 2021 Share Posted February 22, 2021 The reviews were Google at 2.7 and Trustpilot at 2.8. May not be at all representative. The only time I have specced UFH has been John Guest and Nu-Heat but for new build. The system you propose will chew through lots of fuel. Just about acceptable in a bathroom but not a whole flat. If you have decent ceiling heights you will not notice a threshold at the entrance door. Most houses have this. If you can get min 30mm Celotex type insulation under I will give you my blessing for underfloor heating. Link to comment Share on other sites More sharing options...
Dave Jones Posted February 22, 2021 Share Posted February 22, 2021 underfloor without insulation is a total waste of time and money. dont bother. Link to comment Share on other sites More sharing options...
swelliott Posted February 22, 2021 Author Share Posted February 22, 2021 Thanks again Mr Punter. So at the moment, when I step into the flat from the outside hallway, the level drops 40mm. I could alter the height of the door so I have to step up slightly when I come into the flat instead. If it's only an inch of so, that wouldn't be that noticeable but would give me about 60-70mm to play with instead. If I was going to lay something like 30mm of celotex down throughout the flat, what type of UFH would I then be looking at laying? Would it be like a floating system with the panels instead of castellated trays? Would I still need to pour screed on top? Link to comment Share on other sites More sharing options...
TonyT Posted February 22, 2021 Share Posted February 22, 2021 If you are flipping the flat for profit, what gives more profit. Radiators or UFH? Link to comment Share on other sites More sharing options...
swelliott Posted February 22, 2021 Author Share Posted February 22, 2021 33 minutes ago, TonyT said: If you are flipping the flat for profit, what gives more profit. Radiators or UFH? Installing rads would keep my costs lower and you would therefore think that the profit is greater. However, there are 2 caveats to that. The first is that UFH is more desirable and would demand a slightly higher price on resale, therefore making my profit higher by spending more in the build. The second is that although I'm in the business to make money, I'm not one of those developers who doesn't give a s**t about the buyers and would prefer to sell my properties knowing I've done a good job that the new owners will be happy with. Link to comment Share on other sites More sharing options...
TonyT Posted February 22, 2021 Share Posted February 22, 2021 You can’t say you are going to do a good job if you aren’t insulating under the UFH. ? 2 1 Link to comment Share on other sites More sharing options...
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