Green Building Forum - Underfloor heating upstairs.... Sun, 05 Jul 2026 02:35:28 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306186#Comment_306186 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306186#Comment_306186 Mon, 08 Jul 2024 18:10:21 +0100 Victorianeco
Has anyone done a cost to benefit calculation on various methods?

I'm thinking:

A. 50mm PIR insulation between joists sat on roof batten, 16mm pipe in a 50mm biscuit screed (potential issues for weight?)

B. Spreader plates with rockwool insulation below

C. Any other alternatives whilst the boards are up?

We have approximately 100m2 of upstairs floor area to do. Finished floors will be 18mm OSB with underlay and carpet...]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306187#Comment_306187 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306187#Comment_306187 Mon, 08 Jul 2024 18:21:00 +0100 Simon Still
https://www.wundagroup.com/water-underfloor-heating/joisted/
www.wundatrade.co.uk

they don't seem to sell the system we used, which was an overlay on top of the chipboard floors (so took about 20mm) in fibreboard panels. We've got acoustic Rockwool between the floors.

On upper floors the considerations are a bit different - you don't necessarily need to create a load of mass (especially if you run continuously at low temperature)

(Most of our upstairs rooms get enough heat transmitted from the floor below and we don't actually have the UFH circuits on)]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306188#Comment_306188 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306188#Comment_306188 Mon, 08 Jul 2024 18:26:46 +0100 tychwarel its cheap and very easy to fit]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306189#Comment_306189 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306189#Comment_306189 Mon, 08 Jul 2024 18:38:53 +0100 Victorianeco
I always thought a screed mix would retain heat better and also allow a better area of heat transfer. This was what we used in our last house in the first floor bathroom but with tiled floor on top of ply.

Tychwarel any issues with noise of plates heating up and expanding etc? I think this would be fastest method of construction, and of course time is money. Do they give enough heat to transfer through the finished floor?]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306190#Comment_306190 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306190#Comment_306190 Mon, 08 Jul 2024 18:43:06 +0100 tychwarel Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306191#Comment_306191 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306191#Comment_306191 Mon, 08 Jul 2024 18:46:54 +0100 Victorianeco
What temperatures are you running and any suggestion on a supplier for the plates? They seem very expensive for what they are...]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306196#Comment_306196 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306196#Comment_306196 Tue, 09 Jul 2024 07:45:04 +0100 Dominic Cooney It was where the loops of pipe crossed over the floor joists, we chiselled them into the top because the joists are existing and very old and rock hard pitch pine. Should probably have gone through half way down but that would have been even more epic.
Low temperature for us due to GSHP usually 30-35 degrees C
We used 18mm solid oak floorboards as the structural floor and finished surface I had to be very careful screwing them down (hidden fixings through the tongue) to avoid any pipes.
I prefer hard floors to carpets.]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306197#Comment_306197 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306197#Comment_306197 Tue, 09 Jul 2024 07:52:09 +0100 Dominic Cooney underfloorparts.co.uk
Probably the cheapest I could find, but maybe they had the size(s) we needed because we had some odd joist spacings! I had to plan it out carefully to work out what I needed and where, and the pipe route.]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306201#Comment_306201 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306201#Comment_306201 Tue, 09 Jul 2024 09:26:23 +0100 Dominic Cooney Top left is "under bath", and there are some void areas over MVHR pipes because there just wasn't enough room for everything in the floor void.]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306203#Comment_306203 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306203#Comment_306203 Tue, 09 Jul 2024 10:10:23 +0100 Simon Still
Low temperature for us due to GSHP usually 30-35 degrees C

That's not really that low - the heating curve for flow temp on for my upper floors (overlay under wood/tile) only hits 29C at 0C external (32 at -10).]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306206#Comment_306206 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306206#Comment_306206 Tue, 09 Jul 2024 11:11:52 +0100 Dominic Cooney In my head 20 degrees water in the pipes would give 20 degrees in the room, but I was soon disabused of that concept.
I guess the heat loss of the room/building is critical, it’s needs heat input faster than it loses it.]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306209#Comment_306209 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306209#Comment_306209 Tue, 09 Jul 2024 16:19:08 +0100 Gareth J Posted By: Simon Still)

(Most of our upstairs rooms get enough heat transmitted from the floor below and we don't actually have the UFH circuits on)

That's something my folks say about their barn conversion which has UFH downstairs and rads upstairs. Radiators are only on very occasionally.

Similar in our cottage. There's no heating upstairs except bathroom/ensuite. Occasionally we run out filled rads in bedrooms as and when.

Have to wonder about the economics/carbon investment in installing heating upstairs if it's only used barely ever. Regs are regs though I guess.]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306210#Comment_306210 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306210#Comment_306210 Tue, 09 Jul 2024 17:38:16 +0100 djh Posted By: Gareth JRegs are regs though I guess.What regs are there nowadays?]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306212#Comment_306212 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306212#Comment_306212 Tue, 09 Jul 2024 17:57:15 +0100 Dominic Cooney Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306215#Comment_306215 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306215#Comment_306215 Tue, 09 Jul 2024 18:23:22 +0100 Gareth J Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306240#Comment_306240 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306240#Comment_306240 Fri, 12 Jul 2024 13:32:24 +0100 Rex https://lewismetaldeck.com/) on my first floor but the structural engineer told me it was not possible.

Have the pipe in polystyrene insulation with spreader plates. Heating is not a noticeable as the ground floor (screed) but what annoys me is every time the heating come on, the floor pop and bangs. I figure it is the expansion of the pipe where it is a push fit into the plates, but it is really annoying and frequently wakes us in the early morning.]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306283#Comment_306283 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306283#Comment_306283 Fri, 19 Jul 2024 09:09:57 +0100 Simon Still


Posted By: Rexwhat annoys me is every time the heating come on, the floor pop and bangs. I figure it is the expansion of the pipe where it is a push fit into the plates, but it is really annoying and frequently wakes us in the early morning.


Interesting. What's your flow temperature? suspect it's far too high. Our Wunda overlay system in fibre mats with spreader plates has never made any noise but flow temp is 21-30ish.

Posted By: Dominic CooneyWe resorted to Oil-filled radiators in the bedrooms in the last place we did, because they could get too cold in winter. We assumed that heat would rise, but obviously it didn't do so quick enough. Which is why we put the UFH in upstairs this time. Insulation in the walls wasn't as good as it could be though, due to space constraints.


That's the thing. We're over 3 floors (tall narrow townhouse). The top floor gets cooler but is probably OK, the middle floor where our bedroom doesn't need the UFH).

Ultimate solution now is probably Wet UFH on ground floor and air-air for upper floors as top up/summer aircon (which is justifiable if you're powering off your own solar).]]> Underfloor heating upstairs.... https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306287#Comment_306287 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18157&Focus=306287#Comment_306287 Fri, 19 Jul 2024 13:29:53 +0100 djh Posted By: Simon StillI'm not sure the regulations make any requirements of heating - our neighbours Passive build had only a couple of plug in radiators initially (they've now installed a single Air-Air heat pump unit)I think the regulations require that there is the capability to heat the property (to 18°C in bedrooms and 21°C in living areas) according to the SAP model that is also required. There are specific extra regulations if the heating uses a boiler or whatever.]]>