Thorfun

hmm...but I don't have any soil pipes going under the slab like you did so I feel I need to run the sensors back to the plant/comms room rather that to where a wall will eventually be built and sticking up from the slab. again, talking about sensors in the slab at the moment so once they're in they're not coming out!

but the sensor is out the end of the conduit so it's in contact with the slab, right? so, therefore it won't pull out as it'll be concreted in?

like this? https://www.ebay.co.uk/itm/124433541502?hash=item1cf8d1297e:g:mTsAAOSwPKlfqoC- how would you know if the quality is any good though? or do you simply install lots of them and if one fails then just disconnect it and wire up a different one!

if I knew what you were talking about it might be better. but, I think you're saying that I should forget the Wunda probes and either get the Loxone ones or buy cheap versions of a DS18 sensor online.

thank you. will do more reading on this instead of my day job today. ?

just spoke to Wunda technical support and their probes have 2 wires and he said they're not proprietary and should work with other systems. they work with the Heatmiser systems that Wunda also supply so I see no reasons why they shouldn't work with Loxone. @Dan F I do notice that the Loxone ones have 3 wires though. do you know what the benefit of that would be? @Rob99? maybe this is something you would know about?

that's great. thanks guys. I'll do some more research on the probes before pulling the trigger today or tomorrow.

not worked it out nor know the answer to the other questions! can't find much information about them on the Wunda website either (https://www.wundatrade.co.uk/shop/home/quick-shop/wundatherm-quick-shop/controls-quickshop/floor-probe/#)

this is very true. but if I want to test the pipework before the pour I need a manifold, right? although from the reading on here the pre-pour testing of pert-al-pert pipe doesn't really seem necessary.

that's a great idea using the pipe as a conduit for the probe. cheers! those Loxone probes seem to be double the price of the Wunda ones which are probably double the price of generic ones. any obvious reason to go for the Loxone ones over the non-Loxone ones?

I'd like to take credit for it but that wasn't me! ?

looks like you need to use some of it to charge your phone! ?

in the slab or on top of the slab? I ask as it they're in the slab then most seem to come with 3m cable at most so I'll have to support them some how to keep them out of the way for the slab pour which could be a pain

I really don't want to know about @pocster's 'electric toys' that he uses in the dungeon but I am also interested in where the stored power in the battery went overnight?

I’m happy to pay £800 for peace of mind. If we never use then great! But at least the pipes are there if we do. thanks for the de-coiler tip. Will look in to it. definitely having UFH on the ground floor but still undecided about the first floor. If it turns out the pipe and manifold are only around £800 then I might just lay it anyway. But that’s definitely a decision I can make a lot further down the line.

sounds like a risky and stressful situation! I wish you the best of luck with it all. as much as I love the idea of the insulated slab (and it appears you do too) it just might not work for everyone. and so maybe a more 'traditional' approach to the foundations would suit you better so you're not so reliant on the lead time for the EPS and you can get the foundations and block and beam floor in and then worry about insulating as the build progresses? as far as I know you can still detail the potential cold bridges out using that route (although I am in now way a builder or very knowledgable in all of this!) so it might be worth considering.

and that is the important question that I don't know the answer to! but, I wonder if you really need to know the temperature of the slab deeper than near the top anyway as the heat will end up rising to the top of the slab anyway. and if you're measuring for running an ASHP in cooling mode and are worried about condensation at the pipes then the pipes are near the top of the slab as well. would those 50mm difference between putting the probe at UFH pipe level in the slab or on top of the slab under the finished flooring really make much of a difference in the grand scheme of things?

I agree with @Russell griffiths and get everything done while waiting for planning. yes it is a risk if they don't approve then you'd have wasted money and have to get things redone. but if you're in a rush then those are the risks you'll need to take. otherwise, you'll have to wait until planning is approved and then get all the calculations and designs done. for us it took about 8 months after planning approval to get the building regulations drawings done and submitted. but our build is pretty complicated with all the different aspects that need to be considered. I'm sure a simpler build wouldn't take so long.

also, just to add, our groundworks company are going to be using Stylite EPS and they also do the L shapes so maybe we will be having them above ground. I'd better add it to the list of questions I have for them but as we need to get the basement built first that stage is months away. https://www.styrene.co.uk/view_full_product/passive_foundation/stylite_passivehaus_foundation.html sorry for the confusion on this! reading back it seems I don't know what I'm talking about.....which is probably true! I do know 100% for sure we're not using 'L' shaped pre-cut pieces for the basement as this is what's being done. for the above ground I'm not exactly sure what will be being done. so I apologise again for the confusion. now I look at the SPI website and see the L shape pieces maybe we are doing that above ground after all.

take the base layer out beyond the slab and put up stands of EPS? if you're concerned then just get a company to design a pre-cut version. takes the risk away. it's been almost 5 months since Brexit so maybe the initial teething issues I hit have been resolved by now. you never know unless you ask.

should say that all of this will/should be designed by your structural engineer. what works for one might not work for another and might be overkill for someone else.

I guess I could also use an angle grinder to cut a narrow and shallow groove in to the slab to accommodate the probe after the pour as well?

no (at least not if I understand the question!). it will be the same as the Kore system just not preformed and not using the 'L' shaped pieces of EPS at the edges. e.g. This is how TSD designed it using the Kore system for the above ground arms: you can see the insulation sitting on the trench fill with the slab poured within the insulation. but we won't be using the 'L' shaped pieces with the upstand at the edge. at least that's what I believe at the moment. we're definitely not using 'L' shaped pieces on the basement so I presume it's the same above ground although that could all change.

hey, @Dan F, quick question on these temperature probes. do they need to be installed within the slab? can they be installed under the tiles/finished flooring and on top of the slab? that would mean I wouldn't have to make a quick snap decision on them to get them in before the slab pour.

by design I presume you mean foundations? if so, the basement and main house is sitting on an insulated slab (250mm thick) comprised of 200mm EPS300 underneath and 200mm EPS100 up the outside of the walls. The 'arm's of the house that are not above the basement are on 2m deep trenches down to the bedrock and then 300mm EPS300/100 laid with a 200mm slab on top. I used TSD for my structural design and they use Kore as their insulated slab of choice so it was all designed as a Kore solution. but it is just EPS so as long as I get what's required if the groundworks company don't want to use a pre-cut solution that's fine by me. They're aware of my requirements and the tolerances to work to for the timber frame and happy with it all. you can check out my blog for more details on some of this stuff.