Oz07

Have you put your supply pipe in yet? What size have you specced? Here you can have 25 or 32 i think. I had the bigger one on last place for better flow rate but think the meter pipe is the same size

But why would you have it banned because it didn't work for you when it sounds like it would suit OP perfectly?

Why short loops @Gus Potter?

No biggie just mail a fillet on when lathing up. Job done

Poor OP getting crucified here because he wants to stick with a gas boiler 🤣. It's like a swear word round here. Not everyone wants to write a thesis on thermodynamics just to get heat and hot water. These new boilers are all coming ready for when they mix the gas too. My prediction is majority of UK homes still using gas for heating by 2050. Tories have said they will scrap net zero legislation, not that they will get in. But the tide is turning on the eco zealotry.

Yeh I think the ratio these could go down to was advertised as quite good but im not really clued up. 15:1 from memory

Yeh the urban plumber guy used a 30 ish kw with cylinder, but the person in the comments implied that these bigger combis can just do everything out of the box. I think the Navien one had some kind of hot return loop to fit. They're not even that expensive so is it just better to go with one of these out of the box and job done?

I watched the urban plumbers youtube video where he made the storage combi. In the comments someone mentioned a couple of high flow combi boilers there was the worcester bosch 50kw which can do something like 22L per min and a Navien 54kw one which also has a high flow rate. Does a boiler like this tick the boxes @Indy? you'd be getting 2 showers at once with minimal complexity

Is there any benefit to internal/external stacks. Assume same temp air inside them so no thermal differences? Just neatness u suppose but square boxing in corner sometimes ruins the room

Just fill it up then as you say see if water drops. I normally put 1m stubs on pipe and test each run when coming out of ground.

Hard to see the plan with it being a photo. Nice big house. Gf toilet looks a bit cramped to me for the scale of the rest of the place.

I just think they would rather deal with something when in occurs and seek to reclaim any costs if applicable afterwards. I just can't see a massive water company coming out to replace a section of sewer for pvc as a preventative measure. Although you do say its already leaking. Is there a build over agreement for this work or not needed?

@JohnMo you've not really answered my question, are you a politician by any chance?! In all seriousness im beginning to come round to your ashp way of thinking but It seems to me you have to be quite clued up, almost an engineer to make sure its designed and set up right. Can they not recharge water as quick as a gas boiler then even if rated to same kW? Does op want the gas to get away from all this boffin stuff @Indy?

They all seem to have these little pvc boxes on now, with holes behind which vent them. You see them on containers in self storage places so they must be good. Have a google for them. Tbf some site containers have panel heaters in too. Might be worthwhile if you have elec.

Good answers here interesting thread. Without wanting to derail too much how do ashp users cope with this scenario? Can they heat water just as quick as boiler? Is it all just about having enough kw? Or do you need massive tanks with elec only system.

Can't see water company doing anything themselves at their cost.

the scissor lift seems like an upgrade! You might have to cut one end of the guardrails off god knows they're hard enough to get in without a wheelchair!

Don't brick manufacturers still have ancient deals where the first merchant to submit an enquiry with your plot gets a % of the sale regardless if you go elsewhere? I've also had it where you get a quote off truss or floor beam or lintel company direct. Tell a merchant and they say we get x% off that and they split it with me for the order. You're right its a minefield

Vexgold worth a call but I don't know how you guarantee its good quality. Have to be there on delivery to inspect and be prepared to send back. James Latham are a bigger nationwide outfit might be worth a call too.

I've always just used the structural slab as the only floor when building with a ground bearing slab. Not used UFH in those though. I normally do hardcore, blinding, dpm, insulation, dpm 100mm slab and job done. Use the self compacting concrete to get a good flat finish. Bet it would be squeaky bum time putting some crack control cuts in the slab with UFH pipes in there! I can't see the logic in putting 2 floors in but obviously each project is unique and has reasons.

Im sure you're right but I think there's a few to many physics / heating boffins here who don't realise how clever they are. Us layman just want our boiling hot rads and open windows!

Why 170mm on top of 100mm slab. That just seems crazy to me, sure there is a reason? Why don't people just put the ufh in the floor slab and have no screed with self compacting concrete? Do you have to increase the thickness to allow for the pipes interrupting the continuity?

Can ct1 be used for glazing units or does it effect the black rubber round the edge? I know silicon is a no no but its hard to find something paintable that is good for this in timber windows

is your house roughly 250m2 net internal space then? If you have a look around here at build costs you could be anywhere from 250k-upwards of 500k so there is a lot of wiggle room on the figures you submit to lender.

Just make sure you have separate building control applications then and explain your method to the BCO he will work with you then hopefully