Muellar

The 3 months was if i was super safe and got the window company out to measure so I'd get a super snug fit once the ICF build was done. I've been quoted a 3 month lead time from measure to supply & fit. I could go firm on the sizes I guess and insert wooden frames made to the size and build to that. Another site I was at showed me how they would undersize the window order by 50mm all round, or make the openings +50mm, and then pack out with XPS/EPS, but I just didn't feel comfortable with that approach. Having read about how you can get movement during a pour I got worried about messing it up and saw the SIPS as a more accurate build route since the SIPS co's would coordinate with the window manfacturer/installer.

Thanks @JohnMo I'd seen you've used Ecobrix and that to me was more 'idiot proof' than a lot of other ICF products. The blocks are substantive so would hold their own. I guess i'm at that wavering point and saw a SIPS product that attracted me and would shave 3 months off the programme and now we'll be renting that grabbed me, plus it's a lot thinner even adding in 50mm of cork etc, so I quite liked that as well. Given a number of life changes and i'm from a construction background I'm going to PM the build and have a few good folks I know that are keen to work with me on an ICF build, wheras the SIPS would be a package giving me a shell/roof and intermal walls quickly... but I think i'd be trading off on factors that will make it a home. Lots of great feedback here that has me thinking a lot.

Perceived advantages 😉 are in part due to me liking solid things and the feel you get from that, too many bad experiences of new build TF and studwork/squeaky floors, then our site is exposed as that way we get the views we'll have out over Lough Neagh, so I know we'll get hammered by the wind as I grew up in that area. To keep within planning ridge height without having a sprawling footprint we also made use of the fall of the land so have a partial basement - making one part 2 floors with only 1 appear above external ground level. I'm also a 'believer' in thermal buffering/mass as well so the whole thing stacked up to me for using ICF and I liked the idea of a thinner EPS layer inside than outside. I've always felt that cavity/brick-block has had it's day so that wasn't on my list of desired building forms. We will clad the whole thing partially in metal including the roof, standing seam either zinc or greencoat plx and the rest in charred timber, so in part what's behind those doesn't really matter. And yes... this whole discussion and the points you are all providing are swaying me back to ICF - although I get that you @sgt_woulds would see another method as being better than ICF. I'm guessing due to the carbon load of concrete from your comments?

This wasn't on my list as i'd discounted TF some time back purely due to a number i'd visited that didn't give me a feeling of warmth. I guess it's maybe due to them having been thrown up and if done proprely they'd be great but the dye was cast and i've yet to experience a TF home that gives me the feeling I seek. Sounds like you've got it right though, typical eh.

Thanks for that feedback Kelvin. Our site whilst not in a built up area or on a flight path is exposed so we will get a lot of wind noise, plus livestock in the fields and crows.... those crows make a heck of a racket. Noise is a key factor for us and is one of the reasons ICF appealed, ain't much going through c 155mm of concrete and triple glazed units. It's starting to look like we'd be best putting up with the longer construction time ICF has and getting the detailing right early given we hope for this to be a home we'd live in for 20+ years.

@SteamyTea - as we've got an exposed site and building in Northern Ireland the desire is for a quiet energy efficient home. ICF attracted me but then recently I was shown homes that are similar built using SIPS, my concern with SIPS was that they'd fluctuate too much with the external temps due to lack of mass/density. Reading other threads on Buildhub led me to the UBAKUS site. In turn that led me to taking the standard SIPS build-up I was given and adding cork EWI to see how it would improve the U value to be similar to the ICF and what the resultant decrement was. I was happy with the ICF results I had and to answer your question I guess I am after a 'model wall' based on the ICF characteristics. All other factors I'm good with - glazing/floor/orientation etc.

@JohnMo - I got the U values on the SIPS with cork to be similar to the ICF build up I'm considering so the comparison was as equal as it could be on a U value basis so I could see the difference in decrement values. I did wonder about SIPS and noise but have seen a load of examples of the SIP i'm interested in being built both in city centres and on exposed remote sites (similar to ours) and was told they are quiet. You've got me wondering now.....

Hello I've progressed a house design using ICF, but got concerned at all the detailing so that various things could be installed - from boxed/hidden blinds to fixing of heavy items - and this made me consider SIPS as an alternative. My gut feeling that having density/mass in a build was a good thermal buffer and then reading through various items on BuildHub I found out about decrement and then UBAKUS so I inserted various build profiles to see what the results came out based on a base SIPS option i've seen and then adding 45mm of cork to the outside and finally an ICF build up I like. The benefit of SIPS over ICF now looks to be on the increase I'd get on the internal floor area, with a fixed external allowance, as well as ease of future fixings for what looks to be a marginal benefit due to the difference between the increased phase shift that ICF gives when I look at the temperature difference on the inside surface. Have I got this roughly right or is there a better way to look at this? I have included screenshots of the output from the software for the 3 main scenarios i've considered.

Thanks Gus, appreciate the points you've put out, all very thought provoking and gave me plenty to consider. 1. There is plenty of bearing each end as that 8.4 is clear. For access we can get a crane up to lift all the metal into position from the lane. It is a cost, but better that than splicing I felt so we'd get all the metal we need lifted in and stored in a laydown area we have. 2. Good idea, but that would kill the open plan kitchen/dining/living we've planned. Maybe we'd add more support, but then i'd have to balance the cost of 2x extra beams against the saving in depth. My gut is telling me it'll just add cost for marginal benefit though 3. We are 20km from the sea 'as the crow flies'. 8km from the shore of Lough Neagh but that's freshwater. I'll update when I get a few sketches together. Currently in the process of selling our home in England and there's been 'hassle' but we are back on track so that took my eye of house build items. D

I got a response from the SE and we could go with a reinforced concrete beam but the depth would increase to 650. With the ridge height being tight I'd prefer to have the 457 UB and pack at bottom with a timber stud then ICF so the window installers can fix into. Same for the ICF, I'm thinking we could pack the UB with timber and then fix the ICF into that as the UB will basically fill the cavity so I can't see much concrete getting into the gap - but I am a rookie here on the build out so maybe it's what happens?

As @Gus Potter sets out it became our requirement. Once you stand on the plot and can see the view you'd realise and i appreicate that's not easy here. We've had good friends point out the issues to us but once they've been up at it a couple of times they appreicate it and why we've gone for what we have. We even found a guy out Lisburn way, Lifesize plans where he projected the plans at full scale onto the floor and at first we said the opening was too large so he added some 'polystyrene' walls and when we sat there or stood in the kitchen we saw how big an impact it had on the overall space and feel. I've added a couple of photos to show the outlook we'd have from what would be the Kitchen/Dining/Living where we'd spend most of the time and is where this mammoth opening is in case that helps with understanding the decision we made. I'll ask the SE why he didn't spec rebar, but I accepted his position as i'm not an SE nor experienced enough. We have used rebar in the rear bedroom to created a cantilevered beam so we can have a clear glass corner window as the rear of the house would have a view out over rolling hills.

We went for such a wide opening as the orientation looks out over Lough Neagh and on a clear day (ok, it is Northern Ireland...) you can see the mountains in the distance. Winter months get the sunset on that side too. The SE has dealt with a number of ICF schemes and has done this before so it gave us flexibility on that opening so we decided it was worth it. Plan is to start build mid 2026 so as soon as I get some photos I'll post them.

We have an 8400 opening. The SE has specified a 457x152x52 beam and we are confirming with window suppliers on their abiltiy to have a sliding door with two sliding panels.

Thank you all for the input. Hope you've managed to have a lovely Christmas and New Year... I've put the effort in too and @SteamyTea i've adapted what you sent to me but only because I'd got the devices and loadings already mapped out given the room layouts and my thinking behind what would be used in each area. So here's my workings, warts and all on the basis of @SteamyTea and his rationale as well as applying BS7671 methodology to what I would suggest as being the ring ciruits just from my gut feeling using a video I saw. As a summary of the sheet: Using @SteamyTea principles I get total daily KW of 7.3 in winter and 4.5 in summer Applying the same number/wattage of devices and using BS7671 I get a total need of 42kVA If i take into account all the considered opinions, i'd take 25% of BS7671 as being most likely demand, so about 10kVA say in winter... It does show the demand that comes out from ASHP purely due to it's wattage rating alone and the application of the code. Heating and cooking is about 50% of the kVA using the code and applying the diversity rules. Maybe i've got it wrong, but without taking a course I feel i've applied it fairly closely. Interestingly, I found this really useful videa on youtube, https://youtu.be/7MhH-k6pEgI and the big takeaway I took from this was as the guy points out, that even in BS7671 it states it's impossible to work out. There's been other things i've seen where an electrician even pointed out that using the code his home installation woudl be illegal, but in reality it actually consumes about 1/3 of what the code would produce, even on a winter day with his kids leaving lights on! So I'm going to stop now and share my workings, but this has all given me the logic to go to NIE and state I don't need a 40kVA 3 phase supply and may maybe not need one at all if I go off-grid, but what would they charge for a 100amp supply and see what they come back with. However the more I've looked at this the keener I am to try and not connect to grid, have a mixed supply (PV, Ridgeblade, Log burner with heat exchanger and a back-up generator etc) and to log it all so anyone can see how well it works. Hope this is helpful/useful to others as i'm very grateful for your input. Electrical workings and key figures_01.01.25.xlsx

Now I'd originally thought of having something like that, but was told 'don't be silly'. i'd seen a Woodfire EX15 that i'd quite liked, and had seen that not only would it be a nice feature, but we'd also have back up should things go bad - like recently during the storms and power went down. This whole experience with the cost of power has really made me think that maybe i'd dump the whole induction hob thing and go with Calor gas tank for cooking use and also a boiler to be used now and then, with adding in the Woodfire EX15 for use during winter and as a back-up. Then go back to NIE and ask 'how little can you give me' just for small power and other items.

Yes, Northern Ireland Electricity. I've made my own attempt at a sheet but I got an even larger figure... duh. Thanks for offering to knock one up for me, i'm very grateful.

lol... you've reminded me of a Father Ted sketch @Conor, thank you! And yes, it's how I felt when I saw the calcs come through I just couldn't believe the figures being presented but they stood by their calcs and this is an area I get confused in so I left them to their stuff being told by the architect they were good and could 'work wonders with NIE'.... unfortunately not the wonder I'd hoped for.

I assume so as the engineer did all the dealings. I've seen he's said that NIE will want to upgrade the transformer to a 50kVA regardless of what we want as it's currently at capacity. He said that a home such as ours from his experience would need 35-40kVA and we can have that but as single phase, not 3 phase. My conclusion is that NIE are holding a gun to my head now as they want me to pay for a transformer upgrade even though i'll only be 1 of say 20 properties drawing off it of which several are farms with milking parlours!

hope you're sitting down.... engineer came up with peak demand of 40,000 watts, so suggested a 3 phase supply of 41 kVa. I'm being told that I can have all the supply needed but as a single phase and not three phase supply. I reckon this is why the cost is as high as it is.

I tried this and got myself in a pickle. Created various spreadsheets and am now completely confused by the whole thing which seems to be a bit of a dark art to me. My current view though is given the feedback, is that i'm very tempted by the micro CHP route and getting a Calor gas tank put in. That way I transfer all the heating load and electricity gen to that particularly during the winter months when the PHPP calcs show the need. Once we are outside of Nov/Feb the heating need drops off, then CHP would decrease till we get sufficient from the PV/Batteries.

It is up on a hill but NIE have said they need to replace the whole transformer and want to charge me for that as opposed to just adding in my portion so they are playing a game in my view with me as i'd heard the transformer was up for replacement in any case. Now i've been looking into this seriously I'm tempted to go the CHP route that @SteamyTea mentions and using that at least for all the heating. To me it makes sense as winter months is when I would need the heating and is when PV output would be lowest, so having CHP doing that at least would be the way to go. If that get's me below a threshold then great, maybe NIE will see sense. Moving the house isn't possible.

We've got 300m2 so I guess size is maybe the issue as we've got a very low overall need for heating as a result of the ICF/Flooring/Roof and glazing (most glazing on South/West). All indications were we only needed a 6-7kw ASHP. The micro CHP may be the way to go given the cost NIE are wanting to upgrade the transformer and lay in the new supply @£35k. it may be that I just have to 'suck it up' but I feel they want a silly amount for what is a well designed home.

Thanks @SteamyTea... i've already got a quote for 5.22kw PV array with 2x batteries/inverters etc, but that won't deliver that amount all the time so I'd thought of adding in a wind turbine as we are on a hillside. I see there's micro CHP which could be a route as that would supply the heating/hot water so woudl offset what the ASHP would have consumed. Ideally I need to find someone who can do a proper calculation on the power needed so I have that with more certainty that the bowl of porridge it currently is for me!

£35k to have the connection to the grid via NIE who want to upgrade the local transformer.

Hi I've had a crazy quote for power supply and wondered if anyone has had experience of going totally off-grid at least for electricity supply and if there's someone you've known of who's been able to solution up a whole system? I'd already got plans to put in a 5.2kW pv array with battery packs etc and I'm thinking i'd be happy to go with the extra cost of a wind turbine (which will need planning) and then a back-up generator, but i'm lost as to how to work out the calculations with any degree of accuracy. Merry Christmas and best wishes for 2025. David