Leaderboard

Gut feelings can be quite misleading here. A fact that is unfortunately preyed upon and encouraged by the concrete industry. I'd dig into Jeremy's post above. As a general rule in building, unless someone can attach some SI units to their statements they've not grasped a full understanding.

I suppose I should add that I found myself, a few days back, wondering about exactly how much wasted ( diverted ) energy would be spent maintaining a "passive" dwelling that had not been designed with some degree of management for unwanted / nuisance solar. I believe it would be significant, eg a shameful waste. Even having excess PV going into that endeavour seems a little grotesque from a design PoV, and it should, instead, be going into other strategic energy storage for self consumption. "Fabric first" as always, wins the day.

This is one of those topics where 'in my opinion' folk like to say how their house is so good they don't need it - bit of a look how big my schlong is statement. Yes, in a passive house the first floor will generally be warm enough without, but the outlay is minimal and the benefits worth it imo. We talk about oversizing ASHPs to make them work less hard etc, why wouldn't you over size the 'emitting' surface within the house so it is easier to warm up/cool down. When folks are insulating their houses to the hilt and making them airtight and sticking loads of glazing in, keeping cool is a far bigger issue than warm. The use of an ASHP in cooling mode seems a go to approach on here to help in that sense, surely having twice the surface area when using the ASHP in this manner is one of the key points in favour of installing UFH upstairs. For context, my own build is 0.1 U Value for walls, floor, ceiling, triple glazing and 0.2ACH. Keeping warm is not an issue and was never going to be, I put the UFH in upstairs for other reasons, keeping tiled floors 'feeling' warm and helping to cool in the warmer months.

Your icf house should be airtight without any internal finish. I tested mine before plasterboard and got a good score, big mirrors, cupboards, flatscreen telly, fix a chunk of 5/8 ply behind the plasterboard, then just board over. Externally, mine sat outside with no external protection for 3 years, you can stand there with a hose on it if you want, you won’t get any water penetration if you pick a good icf and if you detail the window and floor junction correctly. The only thing that hurts it is UV.

Yes, don't see why not. Our place, when we bought it, already had a 3-phase supply but a meter on just one phase. Also, it might be easier to get a supply in place with someone on a single-phase (which should happen quite quickly) and then request upgrade to three-phase afterwards. If this takes a while it won't be an issue if you aren't using it.

Yes I built my own, but I "cheated" and had separate current clamps for power going to the house (consumed power) and power coming from the inverter (generated power) so that made life easy. Before that I did experiment with a single current clamp and comparing the phase of the current waveform to the voltage, but although it worked, some loads, I recall the washing machine in particular, really confused it. If you are going down the road of roll your own, look at the electricity meter chips. They have cracked this to perfection so they should be able to separate import and export for you to use.

Thanks, and agreed. My ethos is prevention vs cure, so where some designers will give you the option to go 'full throttle' to cool a home, I prefer to simply work on preventative methods to stop it getting hot in the first place. With successful management ( by using controls with a tight hysteresis ) the runaway should never be more than a degree or degree and a half, eg the uplift over the time taken for the controls to recognise that occurrence and for the system components to have kicked in to respond to tackle said unwanted uplift. A correctly designed system, in a relatively relaxed state, should not struggle to bring that back down in a reasonable timeframe without having to become too aggressive in its response. To cool a house down that has been left to runaway to, say, 24oC would almost need air con to drag it back down, given that by then the fabric surroundings would have had time to achieve that new ambient and would be holding on to that heat energy for a much longer / extended period of time, ergo the 'response' would need to dialled up then from a whisper to a shout. Each dwelling / instance is different, so I review each case uniquely, and on its own merit, in my day to day business. Comments here, however, do sometimes generalise a little, but it is a widely differing crowd on here with varying dwellings / installed systems / wants / needs, so we do our best to cater for all.

Boosting helps increase the transfer, but transfer will still happen at standard flow rates. Our first-floor non-boost flow rate is 145m3/h which should equate to 1.5kW/1.8kW cooling/heating. If this is "useful" or not, will depend on the specific build and your goals. Our whole-house cooling load is just 330W so, along with UFH on the ground floor, 1.5kW is enough to "trim" things on the first-floor on the hottest days of the year. Our total heating load is around 3.5kW, which can easily be covered with UFH but having some output on the first floor helps avoid befrooms getting chilly on the coldest days of the year. What we found this winter is that even with MVHR on low at night the air suppy (after heat exchange) is enough to lower bedroom temperature to 17/18C even when ground floor is a nice 21C. This approach was based on feedback from others with MBC builds that were very happy with just ground-floor UFH as primary source or heating/cooling, but commented on the fact that on the hottest/coldest days of the years bedrooms could be a few degress higher/lower than the ground floor which wasn't always ideal.

I had this post stashed away in my scrapbook (ideas and great things others have done) so may help with the hep2o manifold ideas

1st time self builder here - project managing myself and luckily have the time to do so. Builder is great and knows a lot of the other local trades who he trusts. They do a proper job at a reasonable rate. Some trades have come through him such as groundworkers joiner and sparky and others such as the plumber specialist roofers and windows have sourced myself.

Another plus is If you get the trades in yourself You can pick and choose Where as your builder will just ring round and get whoever is available Fast =£££ Especially on a self build

ps. read through the many blogs on here and it will give you an indication as to what is involved if project managing the build yourself.

congratulations. now the fun begins. as @nod said, the builders proposed route seems to be quite common, especially amongst self-builders who wish to get more hands on. you'd basically be taking on the role of project manager which will definitely make it cheaper but will also take longer. This is the route we've taken with our timber frame. we organised the groundworker to get the basement dug and built, the TF company to build and erect the TF, the roofer to fit the slates, the window company to do the windows, the chippie to do the cladding etc. it is a lot of work and takes up a lot of your time so you need to be aware of that. you need to ensure that required materials are on site at the right time and need to co-ordinate trades etc. but it is doable and, although stressful, is very rewarding. best of luck and we look forward to seeing how it all progresses.

185mm gross is a healthy amount of PIR, so I would stick with this tbh. Now I see the 60mm internally the concern of cold bridging from the frame is dealt with. Don't apply to the outside, as others have said, as it will unnecessarily complicate things ( with little reward imo ). Looks good as-is.

This arrangement is becoming quite normal With many builders struggling to find trades to first and final fix It will certainly work out cheaper But take longer than a turn key If your not on a tight deadline It will be an arrangement that will suit you both

I would do wet or even electric UFH in bathroom/ en-suites and electric towel rads (for towel drying, not heating 300 to 400W). And provision for an electric panel heater in bedrooms. UFH in bedrooms has no real place, we have it and its a complete waste. Very slow to heat up and even slower to cool down. You need (possibly) a warm hour in the morning and evening. But cool when you go to bed. I would keep the cash in your pocket.

We are having the top half of one gable end clad with ash thermowood, in horizontal feather edge style. The rest of the house will be rendered with EWIPro Silicon render. We are not doing anything to the ICF before the cladding goes on. The ICF supplier will have construction details for all types of external finishes and what is required.

I think you are looking at something poorly done and think it’s all like that. why can you see through the wooden cladding ? Obviously it must be an open joint system, in which case they have obviously used an incorrectly specified membrane. do you want open joint cladding? Icf can be covered in what ever you want, you then just use the correct mounting system. there should be no reason you can see a reflective membrane under it and I hope for their sake it was all taped up or they will have all manor of creatures living in it. pic is timber on Icf.

Do a test run and see if it butts together...?

DO NOT PUT POLY ON THE COLD SIDE OF THE INSULATION! Vapour control needs to be on the warm side. if poly it needs to go I prefer no membrane but you could use breather layer. inside I would add insulated plasterboard or insulation and plasterboard, Best to get this from the US as sounds like 24” centres and we use 600c/c thicker the insulation the better and so could you add more externally?

Mangetout peas? Silly!

Sorry?

It'll be fine with a top coat!

I wouldn't cross the road to piss over Wren. Showroom is drop dead gorgeous, killer salespeople, "buy now or your children and the planet will die before you get back in your car".....etc......and then nothing after you have left and have paid, other than two fingers when the order all arrives smashed to bits by an over-worked angry delivery driver and huge turn-around times to get replacements 'when they can fit you in'. I lost a lot of money on 2 of their installs, when replacement panels and cabinets etc kept on getting redelivered by the same angry driver in the same state. The builder had to threaten the driver with a slap around the face due to just how badly he was treating the clients order whilst getting it out of the wagon and lobbed onto the pavement. 7 damaged deliveries of key decor panels which halted the whole install, and when the client went to the showroom to protest the showroom manager took over and got the transport manager to deliver the new white gloss decor ends, and proudly opened it up, removing all the 34 layers of bubble-wrap, to reveal the new hand delivered panel, damage free, in fcuking grey.