Nickfromwales

That 1800x420 on the long left wall....why is that a vertical? That should be a double rad, same height as the 600x700 and then the '1800x420' rad should be sent much further down that long wall, eg towards the bi folds. That arrangement will create a cold 'end' to that room as the vertical rad to the right of the bi folds will do next to nothing unless it's roasting hot. You show T50 which is not much use to a vertical / decorative radiant panel like that (which doesn't convect well at all). If you aren't having 2x vertical down there, and the one one the long left wall can be a big type 21, then you'll be fine if the other 2 600x700 are both type 22's. Type 21's do look far less intrusive in open areas, but you still need more heat in that space imho (I've been installing CH for 30+ years btw). If the type 22's don't fit the spaces they are in, then simply make them longer type 21's. Much better to be turning a big rad down, as you cannot turn a small one up , plus if you then end up running much higher flow temps the boiler efficiency will drop off at a steep rate.

Hi. As the 1st floor of the property is within the heated envelope, the insulation your architect suggests is completely unnecessary (redundant). 25mm would do the square root of zilch anyways with UFH, so the subfloor would get heated regardless of it, and I personally think you'd be better off with the thicker screed atop the (22mm?) deck boards. You simply lay the membrane, tape and staple it down as required (do a good job of this), then clip the pipes to the deck with clip rails or simple nail clips, and pour the screed. Prob a good idea to put expansion joints at each doorway / threshold as this will run at a slightly higher temp than is 'ideal', eg so it is responsive and can cope, and will therefore expand and contract a little more than say a slab would; not so important with wood floor, but defo at any transitions (wood meets tiles of a bathroom etc). Without seeing the house or being in possession of any proper details that's the best advice I can give here of course

And on EPS, anyone who says they haven't had at least a minor blowout was either very lucky, lying, or braced it all enough to make a bamboo scaffolder happy

Yes, was a shock for that client, but even with very meticulous builders on site that was the max undulation that they had to overcome. There are different experiences from different members, please all remember that these are simply my experiences and folk can do as they wish with the info, but I am an advocate of people knowing there's a hole in the ground ahead of them, vs offering them a ladder to get out after they've fallen in said hole.....better to know the pitfalls in advance of making a choice, and then you have the ability to make your own, informed, decision. @MCoops are you decided on a type yet? Just I can adjust the info to be more focussed on the preference vs generalise etc, to get you over the line a bit quicker. Are these to be dwarf walls, or full elevations with a full oak frame within?

Ok, thanks, I’d never asked the question, but interesting to see them how Isotex seem to have tried to limit the bridges. A very different block to the Durisol. Velox different again as it is a totally separate internal leaf after concrete, this offering up the best option for an airtight build, but still needed a huge amount of time / labour / materials + liquid AT membrane (Passiv Purple) to parge and seal to airtight before dot n dabbing. Just sooooo much additional work. 🤷‍♂️😵‍💫

Nudura had a major advantage of being an 8’ long block which gives quicker lay time and straighter walls. Annoyingly it’s a Canadian product ,so the inset nylon(?) fixing strips are at 405mm oc, so our metric 1200x2400mm stuff doesn’t work. Shame they can’t do a different stock model for the UK, but it may be we just don’t buy enough of it. Will need battening then board, unless you become inventive and are happy to stick the boards together and keep the joins away from the strips. Can be done, just an additional consideration when costing up the gross figures. As far as wet plastering directly over woodcrete (if that’s what you’re referring to) then you’re in for a surprise as to just how hard that’ll be. On the Velox build there was an annex done first off, full wet plastering directly to the woodcrete, and required a lot of sets to get it ready to skim. Ended up around 30mm thick overall. The dried out walls had a visible crack around every single block, like the walls were painted over Lego. Took a lot of additional painting to deal with the enormous amount of locked in water that then sat in the woodcrete / bonding / skim etc, like best part of 6 months with heating and MVHR running. Not sure if they carried on displaying the cracks, but they were unhappy enough to take my advice and dot n dab the main residence. The unevenness in the cured woodcrete ICF was nowhere near close to taking a few sets of skim to a finish for paint. The sales patter may suggest this is easily achievable, but it ain’t. 👎. The clients wallet was hit HARD, getting this to an acceptable finish. Very hard. EPS ICF can be buffed out with surface rasps, and is very easy to rid of any undulations. EPS cuts quickly and easily with a hot knife, but woodcrete is a PIG to chase or remove for services. I ended up using a 22mm SDS wood chisel and it took forever installing cables and pipes at the required safe depth.

Worse copies imho, as the block has way more woodcrete bridging between the external leaves to the internal ones, eg far more pathway for air / infiltration and obvs water / rain ingress etc. I'm not posting negatively or argumentatively here because I woke up on the wrong side of the bed btw, these are actual, hands-on, real life experiences that I have had from gaining 1st hand experience, whilst physically being on these projects, and from being on site for the duration from pre-construction right through to completion. I'd be interested to understand which of these manufacturers were early / late to the table too, before I suggested one copied another perhaps? The achievable U value with Velox, for eg, must be far in excess of both Durisol and Isotex, as the concrete core is completely enveloped in EPS, with just multiples of small cold bridges from the metal ties. If you look at all 3 systems pragmatically then this is inarguable, by the design differences and not just my conclusions, and these are the fact based findings of myself, at least.

Yup, as long as you have the depth for the pipework not a problem. You'll need to bin the pan connector that comes with it and get one of these : https://www.ebay.co.uk/itm/133894857870?gad_source=1&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338723872&toolid=20006&customid=Bz5Fkp0jAAAAfGvQfV9LRaaPpc8NAAAAAA The 3" to 110mm adaptor that is supplied with the frame goes on to the new part, and then that goes to a standard UK soil pipe fitting. 👍

Combi defo the right choice if you’re never intending to add solar. If only 2 of you then it’s a no brainer. The cost and disruption to the whole of house plumbing to retro fit an UVC here do not make sense vs the ‘slight’ uplift in gas use when opening a hot tap; bearing in mind you only ever do so WHEN you WANT hot water anyways? There are just too many good combi’s out there, and if the remit is for lots of pockets of hot water through the day, hand / dish wash etc, then the likes of the Vaillant 938 (their heat store combi with 15L of stored hot water on tap) is the weapon of choice. Fitted loads of these and it’s as close to having a UVC as you’ll get without actually having one. 👌. Combi all the way here afaic. 👍

I have direct experience with both Velox and Isotex (both are woodcrete) and these blocks do harbour moisture, transmit it through the block, and are very different to use when stored dry vs left out in the elements. They do dry out, when kept dry though, but are like a coarse sponge vs a teabag. With woodcrete there was defo a presence / visible signs of moisture in the product within the dwelling, particularly on rainswept elevations, but not with EPS, at all. Agree about free flowing under gravity, as that’s how water (rain) was getting inside the builds. It was notable on the lower 1/3 - 1/2 of the internal leaf, but was sopping at DPC. This was its worse at window and door reveals. The sub-contracted builder on that particular project was a very fussy chap too, so this wasn’t down to poor workmanship, quite the opposite in fact as in ‘it’ was getting a helping hand from that chaps team; they were learning and mitigating as they went, to allow for such inadequacies, through his diligence and perseverance. I’d say these types of builds should have the external rain-screen on asap. Regarding EPS ICF, I have never seen the same, and I’ve been around enough of them. A brilliant product in comparison and will always be my go-to when a client approaches me with an enquiry and a preference to do an ICF build. I'm also not a fan of the block having a bridges, or many bridges per block, capable of allowing air flow or moisture to wick, and with EPS ICF you don’t get either as the bridges are either EPS, synthetic, or stainless steel. 👌.

Thanks for this feedback. No need for apologies, folk comment here on their current experiences, if stuff changes then what you’ve done is spot on, eg come back and tell us 😎😉🫡 Not just me that thinks they’re boat anchors. Defo oversold in the ‘bumf’ and failed to deliver big time for me (certified Passivhaus project where I was attempting to shine). Cheers HW 😤. Since replaced with Heatmiser by a local sparky, and I wish I’d have not stuck my neck out with HW EvoHome, hindsight being a wonderful thing etc etc. HW are great for just about everything else, but here, sadly, a complete flop. When you boil the HW EH down, they’re just a really flashy (and expensive) on / off switch, with very few strings to its bow.

BCO will want 1:60 ideally, or 1:80 if needed, but at 1:40 it may fail (if they give a shit that is). They're only really bothered about the ground and down / groundworks / manholes etc, and MAY ask about the SVP / AAV, but not many do tbh.

Any solar PV going into the existing hot water immersion? You’d lose that freebie if you jump to a combi. You’ll have to decide how much hot water you use, but there’s 2 adults and 4 kids (teens & upwards) here and I have a shitty Ariston combi I adopted and we have one bath & shower room plus utility, kitchen, cloak WC, and hot water is plenty survivable for us. If heating a big tank of hot water all the time for just 2 adults then a combi will likely suffice, and newer combis are much better at she flow rates, just get a min 28-30kW size and you’ll be fine. If PV, go unvented & system boiler for the free summer hot water.

👆. At 30+ years of age I’d replace any of the pipework that’s not 15mm or 22mm. “Microbore” needs cutting out if there’s any 8 or 10mm stuff in there. Keeping the backbone and any ‘embedded’ runs is fine, just needs to be flush properly, eg thoroughly, and then a good quality magnetic filter installed to stop any nasty residual crud getting into the new boiler. I’ve done these exact conversions so many times over the last 30 years that I must be in triple digits, so nothing to worry about at all, but the caveat is that you must accept that any pressure related failures will be on your head and not the plumbers; he’ll be connecting to pipework YOU own I’d say > 95% of the conversions done gave us no troubles whatsoever retaining at least some or indeed all of the existing pipe work (except the gas run which will defo need an upgrade).

Yup. They’re fine for internal use. The rest bends will make the flushed water much quieter, so I would do that if it was a job I was doing for a client. 👍. If it’s an SVP then obvs no need to an AAV 👌✔️.

+1. Have you allowed for air admittance, as this will be needed once the flushed water etc gets to the second vertical drop (eg at the outside branch)? Either that pipe extending up the outside wall to become an SVP or a stub-stack with and AAV on it if the former isn’t possible?

What say ‘yea about the detectors being mandatory in plant / equipment stores & spaces?

Having looked at recent plans I’ve had submitted to me by a client, this doesn’t appear to be the case. I know garages must have them, if attached, but not seeing plant spaces (other than when it’s the utility room) featuring them? @Mattg4321? You got your 18th yes?

“@SteamyTea for president!” 🫡

Not heard the sparky’s say that. But maybe because I’ve been doing that for decades anyways, so the subject doesn’t come up. @ProDave?

The fact it doesn’t crush under its own weight is what got me. Clever stuff, and would be great for HA or affordable housing en mass.

Check this out....

Good idea, but the layer of PB in the cavity / sandwich is no-any way you cut this. Please do keep the thread updated if you would, good to box threads of with more info and any resolution you get / how you got there 👍

My thoughts are, if you install “anti-crack” mesh into the slab, then it should be doing its job. I do make sure that the mesh passes through door openings, vs stops at the thresholds and then a new mesh starts again the other side with no crossover. That’s kind of in the idiots guide to tying mesh, but most guys I’ve been around who are installing mesh do this without being asked eg have at least one grid crossover at every sheet to sheet junction. With most good quality flexible tile adhesives you get a couple of mm of decoupling effect from the substrate, specialist adhesives such as BAL offer S1 which had between 2-5mm and S2 >5mm, so I guess getting 1-2mm with regular / popular flexible tile adhesives would be the assumption. Whilst the L shape slab cured a hairline crack appeared, completely expected, and then never changed state. It started prob 150mm inside the outside ring beam, spanned the living room of 5-6m, in the 100mm section, and then disappeared again at the opposite ring beam. I knew the tiles would be fine to traverse this without issue, as it was ‘microscopic’. Pipes are fine, there’s really just so very little movement, and the heating Durand go hot > cold > hot > cold every day, it just warns once and stays pretty constant throughout the winter heating season. Its all good, as long as the guys executing the slab are robust and give at least a slight feck about what they’re doing. All the steel / ground workers I’ve met to date have been spot on with this, including the MBC crew who do this in their sleep.

Just saying what I've been around for 20+ years of installing UFH, and there's never been any issue that I've seen or heard of. On site we tie in rebar to make a frame, add some battens to it, fix all the rising loose ends to that (then test or don't test), and foam around the base at TOC to allow some wiggle room when connecting the manifold afterwards. Yup, loads on here have done the same tbf. Cheap, simple, effective. Just less than great on the knees and back, so the 1st year apprentice or labourer gets the short straw whilst the old guys watch on from the pipe decoiler lol.