Iceverge

Hi @BartW What exactly have you committed to with the TF company and can it be changed? Have you a minimum U value you need to meet? What materials have you paid for so far?

If you're using a company to provide helical screw piles or ground screws they would have a solution. As I understand it they just keep going down until an appropriate torque is reached with each pile which corresponds to a bearing strength. The screw may need to be lengthened with galvanized tubing which is cut off at the correct level once piling is complete.

We put the meter box on the garage and ducted the house supply from there to avoid this faff. An estate of ICF newbuilds near me have the meter box on a stand alone wall adjacent the house. In essence the ESB ( Republic of Ireland Electricity Supply Board) were happy so long as the meter box was adequately accessable and protected. Speak to NIE and ask.

2*2 battens are typically about 45 mm x 45mm, hence that choice for service cavities, filled with 50mm insulation. Going larger brings issues with not being able to use 90mm nails from a nail gun and needing to bang them in by hand or use screws AFAIK. Screws are probably 10 times the price and ten times slower than nails from a nail gun. I would put a 45mm batten on top of the 140 mm studs. With your 15mm gap to the pir you should be able to add 60 mm batts nicely here, no thermal bypass, Then a vapour membrane. Then a 45mm batten at 90 deg to the first, this will cancel nearly all thermal bridges with Insulation and service wires + pipes in here. Then osb and then plasterboard. Rockwool would be fine but again an organic insulant would buy some better heat protection.

Density of material kg/m³ Thermal conductivity W/mK Specific heat capacity J/kg/K Luckily there's lots of resources online. Both predictive and historical. Here's one I just found. https://solargis.com/maps-and-gis-data/download/united-kingdom Not quite that many. More like one in 5 to 6. https://www.lboro.ac.uk/media-centre/press-releases/2021/july/over-4.6-million-homes-experience-overheating/ It's certainly not perfect but it's one of the better ones. I'm not quite sure where you're getting the guess work tag. https://www.passivhaustrust.org.uk › ...PDF UK Passivhaus and the energy performance gap Do we? It depends on what level of accuracy you want to predict to.

I suppose it depends on the size of the users. If it's predominantly childeren or smaller adults it'll be ok. I did some measuring drawing up our place. A toilet needs about 800mm between the walls for "knee space" minimum in my opinion, 1000mm is better. Make a mock up of the situation with 2 chairs ( one as a toilet and one at 90deg as the bathtub and a wall and see what feels comfortable. I've just cajoled my Mrs into the WC with a measuring tape and she was happy with 550mm kneespace. If I did that my lap would be full of wee after a number 2!

Can you move the wall to make more space in that case?

Do you really need the bath? I think this will feel really tight.

Have you planned a fall for your flat roof? Bregs suggest 1:40.

This part here makes me wonder, if you've just been given an off the shelf solution rather than something proper. The 15mm air gap created I suspect is for production builders to who only aim for the minimal levels of insulation, thermal bypass or airtightness. It allows them to drop their 140mm panel onto site, the electricians fix a 25mm backbox up against the PIR, the boarders put a 12,5mm plasterboard over the top and hey presto it all matches with a 2.5mm gap to allow the socket cover clamp the socket "firmly" in place onto the plasterboard. The trouble with that 15mm gap in your case, is that unless it's very well sealed, it'll be able to vent outside air, ( especially in windy weather) making the 125mm of PIR outboard much less effective. Solutions. 1. Can you contact the TF company and see if they can either. 1. Full fill the studs with 140mm PIR. 2. Foam the 15mm gap at regular intervals before fitting the 80mm PIR over the top to ensure that the 15mm air gap behind is trapped in pockets and the air is guaranteed to be stationary (unventilated) As a final touch I would reduce the internal PIR to 50mm, and boost the service cavity to 45mm and fill with woodfiber or similar high heat capacity and higher density insulant sheepswool or hemp batts. This would really improve your decrement delay (phase shift) and help prevent overheating.

Pics always help. What level of use do you expect to get from it? Will it be used 40hrs per week or 30 mins every couple of days? Sheep wool is a nice product but if you just shove it between the studs as is (assuming no membrane externally) , it'll get wet and infested with creepy crawlies. Also your timber frame and cladding will rot and decay without proper ventilation. Post some pics and a solution will be forthcoming!!

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 think one of the keys is to find a hot fill dishwasher + washing machine and cook on a fire of some description.

We have one of these. It works fine. We heat our 300l to about 70deg and blend everything to "hottish" at the taps. I have a mate who does pv solar installs. If you exclude DHW and space heating a very modest solar array and battery can suffice year round. Must ask him again but I seem to remember 2kWp of panels and 2kWh of battery being mentioned. I agree with @jothre the boiler stove.

I should probably ask a more specific question. Can you describe your total wall build up from outside to inside specifying will be done when the timber frame factory has done and what remains to do yours self.

Have you considered an airtight/vapour barrier anywhere in the buildup? If you add external PIR there's a risk of condensate forming on the back of the sheets and rotting the sheathing (OSB I guess). It'll probably be fine if you've got a good airtightness/vapour control layer with no holes inboard somewhere. Airtightness will be much more important from an energy use and comfort point than insulation, what target do you have?

Initially the plumbers used MCLP crimp fittings for us. A couple of thoughts. The system looks like it would be capable of very high pressure as the system mimics hydraulic fittings. I suspect it is almost impossible to get a leak if the joint is crimped properly. Scraped pipes seem to be less of an issue than with push fittings. (I didn't have any issues however) All connections need a special tool, although it could be rented. Its not very DIY friendly if you want to make a small alteration later in that respect. If you decide to change a fitting your only option is to cut it off and throw it away. There's no second chances unlike de-mountable push fit fittings. I found the inner bore of the crimp fittings is quite restrictive compared to Hep2O or copper although in practice the flexitails for most taps seem to be smaller than both anyway. The MCLP pipe is semi rigid which has pros and cons, it can make a tidier setup in the plant room as it retains its shape when bent but is more difficult to cable through joists etc like Hep. The 10mm Hep is almost like running electrical cable. In practice the need to isolate outlets at the manifold individually won't happen that often in a domestic setup. If it does need to happen for a period with Hep2O manifold in a radial system all you need to do is demount that pipe and put in a stopper. 15 secs work. Here in Ireland we still use the old imperial fitting. (bangs head against wall emoji) The MCLP is continental 12mm 16mm 20mm 26mm etc.The fittings we use are British metric, 15mm 22mm etc so a typical connection done by the plumbers was MCLP 26mm pipe 26mm to 3/4 Irish crimp fitting with brass tail 3/4 to 22mm nut and olive 22mm British isolation valve 22mm to 3/4 nut and olive 3/4 brass tailed crimp fitting to MCLP 26mm MCLP pipe. Mental compared with a push on 22mm Hep2O pipe valve on 22mm pipe I replaced it with. Not such an issue in the UK but worth considering how you will combine MCLP and British fittings. Another point ( I know people will tell me to use a water softener) is that with all plastic and Stainless Steel Hep2O won't degrade like copper/brass in an acidic borehole water situation.

We had a mare with ours. I ended up redoing all the plumbing myself in Hep. It's an excellent system. We had a 13m run to the kitchen tap so in the end I ran a 10mm pipe to that too. About 5-6l/min flow rate. Not as much as the 8l/min for the cold tap but perfectly useable. It might be a consideration if your distance is large. A manifold radial system works a treat. 10mm for all hot basins straight from as near to the cylinder as possible. It works a treat and the difference is really noticeable compared to the ones I left the 16mm pipe from the plumber in place. Hot water in 5secs instead of 25. Pipe is cheaper than fixings so I don't think there'd be much of a price difference. You get the added benefit of having no fixings hidden anywhere in case of a leak.

ST isn't at the races anymore unless you have only a tiny area of roof to work with.

The shape of the house can make a big difference. If you have just BRegs minimum insulation and the design is, for example a series of interconnected cottages with lots and lots of external wall area, your figures might be correct. Given the scale of your energy bills I echo those above and advise you to get some advice from someone with experience in low energy buildings. It's likely their input would pay back in under a year. Someone with passivhaus credentials would probably be a good place to start. Alternatively if you post your plans on here (deidentified of course) there's plenty of knowledgeable heads who would be able to contribute further. In any case, fossil fuels costs will remain high now apparently due to speculative investment deserting the sector (so YouTube tells me?!!!) and the electricity energy mix will become less linked as the grid decarbonises theoretically swinging the price in favour of elec long term. We'll see.........

If you open the window can and look to see can water drain out to these holes following the red lines if it makes it past the rubber seal of the window. There should be a slot there to allow drainage on the inside that you can see with the window open. You can test it with a jug of water.

Welcome. Any plans to share?

Here is a link to a German retailer that with a bit of Google translate help you can filter by Dibt compliant stoves. https://www.kamdi24.de/kaminoefen-bis-5-kw/FILTER_VERBRENNUNGSLUFT:FILTER_VERBRENNUNGSLUFT_RUU_DIBT However I came to the conclusion an external air supply wasn't as important or useful as it first appears, although it is required by Bregs. Bregs require 550mm2/kW of permanent ventilation for stoves. At 0.31ACH our airtightness result still left 5000mm2 of equivalent leakage in the envelope. In theory enough for a 9kW stove. I'm pretty sure you'd have a tough time arguing that with building control but practically with a balanced MVHR system I can't see a small stove ever struggling for air. If the MVHR is highly biased towards extract you risk pulling fumes out of the stove. Not ideal. I have seen 2 examples of passivhaus with stoves that have good airtightness results. 0.59ACH with a boiler stove. https://mollyglass2012.tumblr.com/page/9 An extract from "Old Holloway" passivhaus. (one of my faves) 0.39ACH. Interesting both use poujoulet flues of different flavours. Maybe no more than coincidence.

This is what they did on ours. I wasn't a fan but was too late to request them change it to precast concrete lintels, I'm not sure if that's an option at your span.

PIV is an option also ( positive input ventilation ) but seems to have opportunistically doubled in price in the last few years. I installed one of these in my parents house last year as it was very damp. It just sits in the attic above the upstairs landing extracting from there to an outside vent. No ducts to any wetrooms. I did this on the impression that if the internal doors are opened occasionally then the humidity will equalise. It seems to be proving right. It has helped to get rid of lots of the mould although they seem to think the house is colder with it running. Hard to say objectively. I did need to install a DIY silencer as it was noisy without one. I can't see where the price increase goes over something like this is however.