Nickfromwales

and ? Passive in the slab and a bit poor where the heat rises and wants to escape?

You didn't say how modest I am?!

Then defo foam it all and let the foam ooze a little to the top. Leave to cure and cut back with a sharp knife or saw, with the cut benched up a little to leave you something to seal to. Wet the area thoroughly with a brush and some 50/50 PVA/water solution and install the foam whilst that is wet (it helps the foam to stick and also allows the PU (moisture cure) to cure without voids etc). Then get some brush on Passive Purple liquid airtight membrane; speak to Adam White of Intelligent Membranes to check if it's worth priming first, but IIRC you can apply that straight to the parge and the plywood. Use a sponge and clean water to rub any residual dust / contaminants off the plywood, do a good job of this, and then use a bit more of that PVA solution to size the plywood (leave it to dry this time). Use a good few coats of the PP where it crosses the foam and sits on the plywood, and leave to dry thoroughly before each following coat. It's really good stuff!

@Annker What are you trying to seal up in that picture? If you're planning to tape the top of those metal hangers then what about the gap on the other side of them? I think you'd be better off with a foam (FM330) here and get it in from the underside and over the top and down, to fully encapsulate the steel hanger where it is cut into the wall.

510mm for a 250L. @G and J, you would still be able to dress a larder unit around it for cosmetics and not know it’s there; plinth should still go on too, with this sitting on the deck, or raise it on a masonry platform if not. @JohnMo, Which HP cylinder did you see at 400mm / 210L for a HP?

Yup. 100%. A tall, slimline HP UVC would fit in there a doddle. Waaaaay better option tbh.

No room for a horizontal UVC under the stairs? I’m doing one for someone else on another new build, where we’ve tried to stuff the M&E into every nook and cranny to preserve useable storage / spaces for living.

Pmsl. GIA needs preserving as I was quite concerned that you might suffer beyond all hope without an attic to stuff all your unwanted useless crap into, eg until the ceilings below began to sag…..like our old attic, lol.

All depends, has the OP stated they have a thick slab? Great if they have, but even then you have a limited amount of time to get heat into such a thing if you want to batch heat on off peak electricity. As above, and always case specific. The very minimum of flow temp is relative to how quickly you can inject heat energy, so low temps with a thick slab requires ‘on constant’ (long and low) vs a thinner screed which will need to be brought up to temp much quicker, and lose it just as quickly soon after. Horses for courses.

You’d just hydraulically separate the heat source from the UFH pump then, so very easy to do tbh. As long as the heat pump can deliver heat higher than the design kw requirements it’ll be fine. I’m a big fan of putting more pipe (therefore more volume of water and cross sectional area for transferring heat energy) into the floor, and that add volume; this can often result in no need for a buffer. This all boils down to the unique circumstances, as no two scenarios are identical, so needs design input and some thought.

Just terrifying tbh, wtf was he thinking?!

I’d go 250L and time when to heat it, so you’re always using off peak power > ASHP. Bigger the cylinder, the lower the stored temp. Any solar planned? Battery?

Are you having a new slab etc or running off / adding to existing? If all new then run ducts in the insulation of the floor and pipe your hot runs that way (as the crow flies) and you’ll not be waiting very long at all to get hot water out of the furthest outlets. If you’re brave, just put 15mm hep into 25mm flexi conduit and set that in first as last, just needs you to babysit (protect) the ends until 2nd fix so the pipe doesn’t get damaged. Can be pulled out and changed if the worst comes to the worst, but better off with 30mm ducts minimum if you’re going to pull these in afterwards.

GIA is important in a “compact” dwelling, so I say to go with your plumbers advice. If someone said I’m going to put your UVC in the bedroom cupboard they’d be sent packing on the spot. 💩👎. Garage for plant, bedroom cupboard for spare trollies 🩲 😉🫡

Use Marmox or Jackoboard (XPS), and you won’t need a VCL. Have the cuts butted up tight and use CT1 to bond the boards to the steel, using continuous lines of it to stave off convection airflow between the steel and the boards. Aerogel vs XPS = near zero real life differences tbh, but if you can use the thickest board you can then every extra mm will be a bonus. I’d avoid PIR as you can’t fix much to it without it delaminating.

@Jilly If you feel bullied, just reach out to the mods and we’ll send the boys ‘round to have a quiet word The management. 💪🏴󠁧󠁢󠁷󠁬󠁳󠁿

Yup. I was wondering how they got hold of load bearing PIR…… I think the block layer has gone rouge here.

Wasn’t that after your family beat you up for trying it at 42°? 😜🤣

MBC use a particular moisture resistant MDF behind the external breather membrane, not OSB3 there, not sure if that’s the issue.

That obvs pushes the stone course out and then requires a suitable extension to the foundation system to accept the load. A low profile faux version would be affixed to the structure, bonded to cement boards mechanically fixed / bonded on the external facades, so would be simpler and cheaper perhaps, but down to the product you eventually decide upon.

Yup. Have a look at a bag and you’ll see tiling outdoors is completely permissible and commonplace worldwide. The product just needs to be cementitious, and flexible, and primed according to MI’s.

That’s as clear as mud, but I think it refers to the 10mm welded plate which supports the outer block skin finishing no closer to the face of the block than 25mm, ergo there will be 25mm of block unsupported. So A methinks, but another pic with the cross sectional drawing should be in your possession too?

By the time a steel got to those temps you’d all be long 🪦 or simply stood outside with marshmallows on long sticks anyways, so it’s all quite a lot of nonsense in a domestic 2-storey house with windows tbf.

Also you can use these LINK inside a regular (more attractive) vent.