Sun, 03 May 2026 10:18:29 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299635#Comment_299635 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299635#Comment_299635 Sat, 14 Jan 2023 18:47:52 +0000 maxsm
How deep will I need to dig down to end up with a new floor at the same level as the current concrete floor?

After digging down I understand the layer order will be: 300mm insulation - DPM - concrete - 60mm wet UFH in screed - 15mm engineered wood floor. Is this in the correct order? Am I missing any layers? What thickness will the concrete be?

In the short-term the wet UFH will be powered by a gas combi-boiler but I may end up with an air source heat pump and/or solar water heating in the future. Is there anything in terms of plumbing/thermostat set-ups I should do now to ensure the UFH is compatible with my future energy plans?

Hope all that makes sense, any advice much appreciated, thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299647#Comment_299647 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299647#Comment_299647 Sun, 15 Jan 2023 23:37:45 +0000 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299649#Comment_299649 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299649#Comment_299649 Mon, 16 Jan 2023 08:22:09 +0000 GreenPaddy
That saves the cost/time of pouring the screed. Depending on the duration of the build, and thus drying out time of the conc slab, you may need to roller-on a liquid DPM over the slab, to retard the vapour upward passage which could cause issues with the finish layer.

Have done that lots of times over the years. Works a treat, plus you've a finished level floor right away, not monkeying around with allowances for the screed, on every measurement.

Skinning cats ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299656#Comment_299656 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299656#Comment_299656 Mon, 16 Jan 2023 11:02:11 +0000 maxsm
@tony: why would you advise the thicker screed layer?

@ greenpaddy: so if I allow the concrete to dry properly I can do without the liquid DPM? and I can't visualise how the a193 mesh works sorry, would I lay the wood floor directly on top of the mesh? (a photo might help my tired brain!)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299658#Comment_299658 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299658#Comment_299658 Mon, 16 Jan 2023 11:27:36 +0000 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299670#Comment_299670 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299670#Comment_299670 Mon, 16 Jan 2023 17:22:11 +0000 Dominic Cooney https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299671#Comment_299671 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299671#Comment_299671 Mon, 16 Jan 2023 17:23:26 +0000 Dominic Cooney https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299672#Comment_299672 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299672#Comment_299672 Mon, 16 Jan 2023 17:32:22 +0000 Dominic Cooney https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299683#Comment_299683 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299683#Comment_299683 Tue, 17 Jan 2023 08:25:28 +0000 GreenPaddy I use the 193 mesh as it's heavier than the usual 142 (?) as walking on the thinner mesh makes it jump around and bend.
There are plastic "stools" to set the mesh on, though my guys tend to prefer the steel "toblerones" (don't know the correct name - steel mesh supports should give you some google hits).
From memory, conc slabs dry out / cure about a mm per day (of course that varies). If you pour the slab early, which I do before the kit is erected, then you may have enough time for curing, and no need for the liquid DPM. It's not a massive cost for the DPM, and easy enough to roller on.
You need to do a bit of floating, to give a reasonable surface of the concrete, but not polished, but certainly not tamped ridges.
If you find the odd low area (ponding) a little latex self level does the trick.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299718#Comment_299718 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299718#Comment_299718 Wed, 18 Jan 2023 12:27:25 +0000 maxsm
@greenpaddy - so do you lay the 'toblerones' directly onto the DPM and then fix the mesh, pipes and pour concrete?

in terms of heat transfer is there any advantage to using screed over concrete?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299723#Comment_299723 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299723#Comment_299723 Wed, 18 Jan 2023 18:17:28 +0000 borpin
Also beware your levels if putting in inward opening doors. Check with the door manufacturer how high the bottom of the door is from the level the door frame sits on (yes I have that T-Shirt).]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299737#Comment_299737 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299737#Comment_299737 Thu, 19 Jan 2023 10:12:19 +0000 Dominic Cooney https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299743#Comment_299743 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299743#Comment_299743 Thu, 19 Jan 2023 13:41:43 +0000 GreenPaddy
Heat transfer, my guess is better in concrete than a screed, but check the heat transfer rating. It's prob not a lot in it, so wouldn't chose one way over another based on that.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299745#Comment_299745 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299745#Comment_299745 Thu, 19 Jan 2023 15:58:58 +0000 revor https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299758#Comment_299758 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=299758#Comment_299758 Thu, 19 Jan 2023 20:16:56 +0000 djh Posted By: borpinAlso beware your levels if putting in inward opening doors. Check with the door manufacturer how high the bottom of the door is from the level the door frame sits on (yes I have that T-Shirt).We have a mat well just inside the front door that allows the door to open without having to go over the top of the bamboo flooring (purely coincidental you understand :) Our other doors are outward-opening, except the patio door that we set the FFL from. (Oops!)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=302716#Comment_302716 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=302716#Comment_302716 Thu, 03 Aug 2023 04:42:09 +0100 wookey
https://www.backtoearth.co.uk/lithotherm/]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=302717#Comment_302717 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17696&Focus=302717#Comment_302717 Thu, 03 Aug 2023 08:05:17 +0100 GreenPaddy