KillyfadNewBuild Posted March 4, 2022 Posted March 4, 2022 Hi All, I was hoping to run past you all our situation with our first floor 200mm concrete slabs. We are being recommended liquid poured TLA insulation on the floor from our builder mainly due to the slab being at some parts ever so slightly uneven, so the poured insulation will work to level out the floor before the screed goes in place. I have on my notes that the architect mentioned with the 200mm concrete slabs you don't need insulation, just lay the UFH pipes and screed over them - which I may have noted wrongly. What have you done on your upstairs, or from experience what would you recommend for depth of insulation and screed? Thanks and as always, I appreciated everyones feedback. This forum as helped me so much in the last few years from an non-subscriber to now a member.
JohnMo Posted March 4, 2022 Posted March 4, 2022 Are you building a nuclear proof bunker? That's one thick floor. What are the rooms on the first floor? How well insulated is the house? What is on the ground floor for heating and insulation?
KillyfadNewBuild Posted March 4, 2022 Author Posted March 4, 2022 17 minutes ago, JohnMo said: Are you building a nuclear proof bunker? That's one thick floor. What are the rooms on the first floor? How well insulated is the house? What is on the ground floor for heating and insulation? Haha great to know we can use the house for a nuclear bunker - it was within the architect's plans for the build to have 200mm concrete slabs up stairs; our contractor who is family connected and we trust didn't flag any issues with the depth. There is 3 bedrooms, 1 with ensuite, a bathroom and a hot press up stairs. The house is well insulated, we also plan for the windows and doors all sealed up with fentrim and key areas sealed. Heat pump for heating throughout the house with UFH upstairs and down.
Thorfun Posted March 4, 2022 Posted March 4, 2022 I'd say it's worth having a little bit of insulation on top of the slab simply to stop all the heat from the ufh going down and just heating the ceiling of the ground floor. even if that's 25mm PIR. I guess it all depends on FFL on the first floor and ceiling heights. do you have the space to put insulation down or not?
KillyfadNewBuild Posted March 4, 2022 Author Posted March 4, 2022 Yes, there is room for insulation and the contractor is recommending some TLA even if it's only a few inches. It seems to make sense to add some insulation.
tonyshouse Posted March 4, 2022 Posted March 4, 2022 If the house is well insulated how come you need heating upstairs?
Thorfun Posted March 4, 2022 Posted March 4, 2022 48 minutes ago, KillyfadNewBuild said: Yes, there is room for insulation and the contractor is recommending some TLA even if it's only a few inches. It seems to make sense to add some insulation. sorry....what is TLA?
Thorfun Posted March 4, 2022 Posted March 4, 2022 46 minutes ago, tonyshouse said: If the house is well insulated how come you need heating upstairs? this is a very good point! 🙂
JohnMo Posted March 4, 2022 Posted March 4, 2022 5 minutes ago, Thorfun said: sorry....what is TLA? thermal lightweight aggregate, screed with EPS beads mixed into it. 1
JohnMo Posted March 4, 2022 Posted March 4, 2022 We have UFH in bedrooms, (single storey building) the issue I have with it, is once it's on, it's on, no turning it off when you want to go to bed, so pretty much a waste of time. If we need the room warm we open the doors and within an hour it's the same temp as the rest of the house.
Thorfun Posted March 4, 2022 Posted March 4, 2022 9 minutes ago, JohnMo said: thermal lightweight aggregate, screed with EPS beads mixed into it. cheers. did a quick google and the lamda value doesn't seem great. https://coreprosystems.co.uk/building-insulation/thermal-lightweight-aggregate-tla/ this place suggests 140mm thick to get 0.25W/m2K U-value and this place https://www.energystoreltd.com/professional shows their best thermal conductivity is 0.043W/m.K which is worse than EPS. so, it seems good if you've got a lot of room but if you're tight on room then PIR and liquid screed will give better results. would be an interesting investigation to calculate the cost difference between those 2 methods. maybe the OP's contractor is suggesting it because it will save him time but may not necessarily be cheaper for the customer.
Conor Posted March 4, 2022 Posted March 4, 2022 We used the TLA and it was grand. Hell of a lot easier than laying PIR boards, and similar cost. Basically zero prep other than clearing the floors and shuttering voids. They did both our floors in a day. We used alpha screed, very good. Stapling in the UFH clips was difficult enough, our stapler couldn't cope with it. But if you have a contractor doing that, then not your problem... 1
Thorfun Posted March 4, 2022 Posted March 4, 2022 26 minutes ago, Conor said: We used the TLA and it was grand. Hell of a lot easier than laying PIR boards, and similar cost. Basically zero prep other than clearing the floors and shuttering voids. They did both our floors in a day. We used alpha screed, very good. Stapling in the UFH clips was difficult enough, our stapler couldn't cope with it. But if you have a contractor doing that, then not your problem... how would you attach the UFH pipes if using TLA on top of a slab or block and beam? using click tracks? or the egg-crate type thing? then put the TLA over the top of that? we have block and beam and I was going to lay EPS but maybe I should look in to TLA a bit more.
Conor Posted March 4, 2022 Posted March 4, 2022 25 minutes ago, Thorfun said: how would you attach the UFH pipes if using TLA on top of a slab or block and beam? using click tracks? or the egg-crate type thing? then put the TLA over the top of that? we have block and beam and I was going to lay EPS but maybe I should look in to TLA a bit more. We used clip tracks, but you still need to staple the bends and any narrow buts where you can't get the tracks down. Plus the tracks themselves need to be stapled down as the will just lift the polythene of stuck down. We ended up hammering in the staples with a rubber mallet. Not as bad as it sounds!!! 1
Thorfun Posted March 4, 2022 Posted March 4, 2022 1 hour ago, Conor said: We used clip tracks, but you still need to staple the bends and any narrow buts where you can't get the tracks down. Plus the tracks themselves need to be stapled down as the will just lift the polythene of stuck down. We ended up hammering in the staples with a rubber mallet. what was under the polythene though? it had to be soft to take a UFH staple, right?
Conor Posted March 4, 2022 Posted March 4, 2022 (edited) 28 minutes ago, Thorfun said: what was under the polythene though? it had to be soft to take a UFH staple, right? Sorry, images in no particular order forst one is the pour of the final liquid screed on top of the TLA/polythene and UFH. The TLA. It's soft enough for about three days. After that, it gets a bit too hard to staple. The TLA goes straight onto the slab. Edited March 4, 2022 by Conor
Thorfun Posted March 4, 2022 Posted March 4, 2022 7 minutes ago, Conor said: Sorry, images in no particular order forst one is the pour of the final liquid screed on top of the TLA/polythene and UFH. The TLA. It's soft enough for about three days. After that, it gets a bit too hard to staple. The TLA goes straight onto the slab. ahh...right got it. so TLA is poured then you staple the UFH pipes to that before it goes off and then finished off with a liquid screed. how did the TLA compare price wise to using EPS? I get the feeling it'll be more expensive but quicker (as is the norm with these things)
Conor Posted March 4, 2022 Posted March 4, 2022 4 minutes ago, Thorfun said: ahh...right got it. so TLA is poured then you staple the UFH pipes to that before it goes off and then finished off with a liquid screed. how did the TLA compare price wise to using EPS? I get the feeling it'll be more expensive but quicker (as is the norm with these things) Works out double the cost of EPS, and about the same as PIR. We have 175m² to do, lots of steel beams and uneven slabs. Would have take ages to get right and didn't have much room for error. 1
Thorfun Posted March 4, 2022 Posted March 4, 2022 11 minutes ago, Conor said: Works out double the cost of EPS, and about the same as PIR. We have 175m² to do, lots of steel beams and uneven slabs. Would have take ages to get right and didn't have much room for error. we also have steel beams and slabs at different levels to the block and beam. I will investigate it as an option.
Iceverge Posted March 4, 2022 Posted March 4, 2022 Save some cash and dispence with ufh upstairs IMO. Maybe a just couple of small loops in the bathrooms for comfort. Espically if you're well insulated and airtight. Fix to the slab and cover all with a thin screed. Enjoy the extra room height. It sounds like your builder is thinking like 2002 not 2022. The insulation is only for very leaky houses that intermittent heating was the only option.
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