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The thing to take from this ( specifically for myself and no dis respect to @Thorfun and @Onoff efforts ) - is that any idiot can build an entire underground house with initially ( and indeed even now ) very little skill /knowledge . I think that’s pretty cool ; but you need this forum for it …

I think after reading both @Onoff's and @pocster's bathroom threads I learnt that asking questions is not a thing to be afraid of on here! so don't worry, learn what you can from us making c**k ups and then still ask away as I guarantee you'll make c**k ups too! 😉

getting better under the expert tutelage of the buildhub experts.

I have been planning to use an ASHP so have pipes at the required 150mm centres. Given the energy situation, I am now less sold on an ASHP vs Oil. If you have a tank full of oil you know you can heat the house, not so it there is a risk of blackouts. We'll have log burners as well but that's obviously faff. Environmental: ASHP: When heating using an ASHP the marginal electricity* will be most likely generated from gas: 0.5kgCO2/kWh electricity / 300% = 167gCO2/kWh of heat Oil heating: 2.52kgCO2/lire / (10.35kWh/litre * 85%) = 286gCO2/kWh of heat Winner: ASHP 42% lower* Cost Install: Hard to say accurately but about the same given the grants available. Winner: Tie Cost to run: ASHP: Assuming 300% efficiency again and current electricity price of 45p/kWh -> 45p/kWh / 300% = 15p/kWh of heat Oil: Assuming 85% efficiency again and current oil prices of 90p/litre -> 90p / (10.35kWh/litre * 85%) = 10p/kWh of heat Winner: Oil 33% lower Personal Energy Security: ASHP: heat demand is at a time of year when personal generation not really viable so dependent on supply. Supply could be subject to interruption (blackouts, smart meter bugs). No flexibility on price. Oil: bar it being stolen, when you have it you have it. Can stock up when price is low. Winner: Oil [Interestingly, for gas, the environmental is much closer 185gCO2/kwh (so ASHP saves just 10%) but running cost even lower though grid supply so security not so good] * Using marginal generation figure as I am weighing up adding an additional electricity load, rather than the average. The longest streak without coal is 67 days, so perhaps should use coal for this calculation: 0.8kgCO2/kWh electricity / 300% = 267gCO2/kWh of heat ASHP 7% lower than Oil That 67 days is unlikely to be over winter. Government plans to ban coal powered generation towards the end of 2024, but that may get pushed back. I doubt these figures include full CO2 emissions from transport, infrastructure, workforce etc.

You can get the grants on a new build but I also think that odds are that the boilers will usually outlast the heat pumps…I still favour heat pumps for environmental reasons ..they are not a perfect solution but they are certainly progressive. That said..I know of the old split unit air conditioner units in much harsher climates that have lasted 22 years so it’s all a bit of educated guesswork but still guesswork

We have a Bora hob that is flush mounted into the quartz worktop - the 2mm expansion gap is filled with black silicone - no issues.

Pass, is there any fire strategy drawings? I appreciate you are doing a lot of work yourself, I don’t get involved in fire risk assessments , just follow their guidance as I like to have others put their insurance/design on the line. but worth looking into sealing of risers/penetrations with some experience. https://www.thebesa.com/media/1409061/firestopping-of-service-penetrations-guide.pdf

Well technically, I think @Carrerahill’s comments were sexist/verging on sexism/bringing sec into the discussion unnecessarily. Anyway, @Jilly’s suggestion is a good one. I will give it a try.

Pellet stove needs a standard chimney or liner suitable for a wood burning stove so if the chimney is in good condition then you will be fine.

You can never have too much log storage!

No, it needs cooperation at both ends of the link. Of course. But IEEE 802.11s isn't exclusive to Apple by any means. Just not so widely adopted.

Then look ! This is the fun stuff !!

not got as far as looking for fittings yet!

Not sure of your choices for fittings . But I mainly went with roper Rhodes . If I hit you with one of their taps it would kill you . I like that . Not killing you ; but the fact it’s not plastic shitty shat crap .

yeah, I know they are. but s**t happens and then you have to cough up the cash to flush it away.

Do you mean the Kappa cistern..? Check your choice of flush plates fit the cisterns as they have different ones for Delta, Sigma and Kappa

Well I have full fill with rockwall batts and a brick face, the insulation has a BBA certificate fir full fill. The west face gets very wet and the bricks were saturated but when core drilling for the ASHP although the inner face of the outside bricks were wet it had not gone into the insulation. As a precaution I coated that wall with sealer and now the water runs of it like glass.

Once you cut back the path and either fill with shingle or have a channel drain the wall should dry out. I would be wary of doing any rendering until it is bone dry for at least 6 months.

Ohh I know the answer to this one!! link 1 is designed to clip over the joint with the legs so that you can clip it on and pull the pipes apart, so you can do it one handed. link 2 you have to press the tool against the joint while pulling the pipe out so need 2 hands! not used the fancy metal ones!

I think you are going great guns here, and I for one appreciate this thread, thankyou. It's going to be so much help for me, who, probably isnt quite so brave to ask questions, advice and show my work.

He has his own brand of wipes ??

I used number 2/ for my hep 2o stuff, not seen the others.

no comment

it keeps things interesting. if it all worked how it was supposed to life would be boring.

I think you worry too much how concealed pipework / wiring looks . I’ve said before a plumber etc. may have professional pride on it looking neat . I don’t 😁 . Also as I’m making it up as I go along lots of things change - there’s no plan . What does matter is of course the finish ; the tiling , decorating , etc. etc. - all the nice bits SWMBO likes .

<visits thread out of respect> How goes the DIY plumbing? Do you hate it yet?

you want 150mm insulation 75mm screed to make 225 to match external brickwork. EPS insulation is cheaper by far.

Asus Zen very good and easy to setup. I have the BT Wholehome setup. Strictly not a mesh system and doesn’t have an ethernet backhaul but it is very reliable, provides terrific coverage, plug and go so no fecking about necessary, is fast enough for our use and has worked reliably since I switched it on. I might choose to swap it all out for the new build but probably not. Everything that is fixed will be ethernet.

that'll make a change.

BH T’s & C’s state that we can bully you at out leisure. No retreat, no surrender.

yes but but caution to use with brick faced walls due to wind driven rain.

This was my build up which gave a u-value of 0.18 if you have a brick outer leaf you would get 0.19, but you have to be very careful using brick will a fully filled cavity due to wind driven rain penetration (you will need to have advice on this) there are products that allow / certified for a 10mm residual cavity (e.g. Kooltherm K106) but the max thickness of this product is 115mm. This is calculated to give a indicated U value of 0.14

full fill with beads or full fill with mineral wool, may even cost less than PIR as well Also, get onto U-value calculator | ubakus.com and have a play

Yup. 1st year apprentice would be sacked on the spot for that 💪.

You just find two bits of wood close together, put a long piece in, and bend it. “Use the force…..”

Last time I looked commercial systems were very expensive compared to PV systems. Just before the PV FIT bandwagon started I installed a large evacuated tube solar thermal system. At the time PV was very expensive and solar thermal was a fair amount cheaper per unit of energy collected. Then FITs arrrived, PV boomed and PV prices dropped through the floor, while solar thermal prices increased slightly, then most of the solar thermal suppliers disappeared as there's virtually no market any more. PV panels are fairly simple mechanically and mass produced on a large scale; from a manufacturing POV evacuated tubes are more complex, use more materials and are smaller scale. A decent solar thermal system isn't particularly simple. You need a pump controller to ensure that the pump only runs when there is energy available, so it doesn't suck the heat out of your tank and to try to ensure that it doesn't freeze and damage the system and try and protect it from boiling and dumping all the solar fluid out of the OPV. Then there's the water temperature issue. It's quite easy to get a HW cylinder up to boiling with a solar thermal system. That means that you should have a mixing valve on the HW output to remove the scalding risk. Additional work and expense. Then there's the effectiveness issue. Solar thermal works quite well in bright sun but its effectiveness drops dramatically with low illuminance levels whereas PV produces linearly so will still harvest some energy in dull weather. And of course solar thermal is a one trick pony. It will heat water and nothing else. PV will do anything that can be done with electricity, including heating water.

I don't understand why it seems it has to be one or the other. What is wrong with having both. If you have the G98? limit for PV already fitted why not fit ST, rather than increase your PV.

Or fill cavity below the void up to the underside of b&b. And then fill with PIR up to your floor insulation.

160mm recticel achieves 0.11...might be a fair compromise? It's 10% higher performing then Kingspan equivalent.

The only time I've seen foil insulation suggested seriously is for retrofit where nothing else was feasible. The idea is that radiant heat gets reflected back into the room to be absorbed. Which is great. but with a well insulated wall, that same radiant heat is absorbed by the wall, so still remains within the same thermal envelope. So what have you gained by reflecting it back in? Foil can make make some improvement in badly insulated walls. But on a new build that is not where you should be. If weight is an issue, improve the foundations.

If you have structural issues foil won't save you. I'd avoid it in any case, most of the performance numbers they claim comes from the unventilated airspaces created within a wall, much like double glazing. Any kind of air circulation would ruin the theoretical performance and it's a renovation so you'll have some air movement. Mineral wool, cellulose/hemp is a better way to stop the air moving. Fire will love those air gaps too if it gets in there. PIR between studs is fine if you like suffering, don't care about summer overheating, of fire risk, or materials wastage! Do you have any pictures of the building as it stands, inside and out? Im guessing that you don't have a tremendous budget so it's important to save as much cash as possible. I think you don't need to remove the tounge and groove boards outside if they are in good condition, just lap, staple and tape a good breather membrane over the top, then some 38mm or 22mm battens for ventilation and some more cladding. Internally you could take down the T&G and put hemp batts between the 6x2 studs. Then cut 45deg tracks in the studs and push in some T L or C profiles to provide cross bracing screwing them into the studs. Then cover and really diligently tape with a good vapour membrane, fix 47mm cross battens for a service cavity insulated with 50mm hemp batts and then reuse the tounge and groove cladding. It could be done piece by piece, fairly cheaply and would be windtight, airtight, have little thermal bridging, good phase shift, breathable, good sound protection, low embodied carbon, good fire performance, low materials wastage.

Please don't. EPS beads or mineral wool batts everytime. Use normal medium density blocks and widen the cavity for better U values. If you can play with the numbers yourself you can see how useless lightweights blocks are as insulation. The difference between 0.15-0.16w/m2k is almost imperceptible and anyway it's unrealistic. Above 0.18 was the best I could make from your above materials.

@Nickfromwales @Russell griffiths @saveasteading, is this better?

qq on this subject. I have a lot of 20mm electrical conduit lying around. can I use that for 15mm pipe? according to this question on the SF page for it so that will give an 18.2mm ID. a bit tight for 15mm hep2o pipe or should it fit like a glove?

With my planning fight I wanted to start the garage workshop under permitted development (a house existed on the site) and I found that any demolition on site counted as “starting” ( I still had to fight that tho) so make sure anything you do is documented.

Just chuck an 80 grit flapper wheel in the grinder and dispense of these acts of tomfoolery…..

Agree, it would not sound hollow or thin if it was full of water. That's why I suggested call DNO get them to identify it. I dug up a small black unknown cable on my site. The DNO were happy to come and look at it, carefully open it up and determined it was a redundant old telecoms cable. They would rather do that and be sure than risk damage to their network.

I am cropping, bok choy lettuce spring onions rainbow chard purple sprouting broccoli kale texal greens radish suger snap peas garlic strawberries all in abundance and having to give stuff away ! It’s amazing what you can do in a small area. I will be getting my polly tunnel up within six months ready for next year as I feel I have outgrown my fish box garden.

That does seem very high. I take it that price doesn't include the warranty. I don't know, but I guess it could be that conversions are more expensive than new builds as the underlying asset of the existing house is at risk. Do shop around as prices vary hugely. SelfBuildZone are another provider to try if you haven't already.