Nickfromwales

Hi. Answers will be along shortly I’ve just removed the duplicate thread as otherwise you’ll just have a volley of replies across both which is a bit messy

Any bare concrete will have dust / other surface contaminants so you primer that before laying any kind of screed or adhesive at a thickness of less that 50mm (normally above that you won’t need to prime but the installers would usually decide this). If you pour some screed onto a dry slab you’ll likely be able to chip it back off in one piece as it’ll have just adhered to the surface dust etc. A bit like you greasing a cake tin. The clip rails add to the mix as they provide a mechanical connection, but should not really be relied on as the only measure. Thin screed systems <30mm need a specialist primer which stays tacky for a long time. Boilers modulate, a bit like you controlling a light with a dimmer switch, so they can match the heat demand as closely as is possible. To drive a non modern boiler into UFH you’ll likely force some short cycling, the boiler repeatedly lights, heats up, can’t get rid of enough heat so hits the internal stat set point, then waits to cool slightly, then lights again, and repeat. That’s can lead to reduced longevity and much deceased efficiency. A buffer / volumiser adds a runoff volume of water, if you think of heat as air, it’s like you blowing up a balloon quickly, and then just letting the air out slowly over the next 10 mins, then repeating, therefore taking the ‘short’ out of short cycling. That make sense?

Hi. What are the floor coverings going to be in those rooms? I assume you’re lifting the floorboards to do the work and install acoustic insulation, and if so you can start by putting 50mm wide acoustic strips on top of the joists for the new floorboards to sit on. Depends really on how ‘mad’ you want to go, but you’ll need to be cautious of what insulation you pack around electric cables / light fittings etc, but the more acoustic insulation the merrier obvs.

I went to one gypsum laid job where almost the entire ground floor of tiles had separated. You could lift a few m2 by putting a chisel under the tile that was centred in the doorway to the wooden floor of the living room. It had been primer coated too, but it was the primer + adhesive + tile that was loose, zero had stuck to the screed so I assume they’d not scraped / mechanically prepped it at all.

Dry sand & cement? Or gypsum? Yup, and the Adrex (A35 iirc) stuff is too expensive to compete against. Undeniably good stuff though, and can take ceramic tiles 45 mins after laying at 80mm. I cheated by laying porcelain the same day, but insisted that the grout was done 7 days later......still alive to tell the tale

I disagree wholeheartedly, sorry!!!! That is a bag of shite, and even Stevie Wonder would agree.

There are an alarming number of dwellings that have had EPS EWI applied, that are now displaying huge amounts of damp and mould growth on the interior surfaces of the external walls, literally stopping at the party wall. This is down to rain getting in at the top, or air convection (aka thermal tenting) happening from the bottom to the top, with the moisture then being harboured by it condensing and then being trapped with nowhere else to go than into the fabric of the house. Do this properly or receive the consequences!

In a real life situation, in a 2013 B regs build which will be poorly insulated and very draughty (sorry OP), I think it will be an absolute necessity to guarantee rooms achieve the desired temps and then stay there. This advice is case specific to this thread and OP, and reflects the unknowns, build fabric, and different floor coverings. Balancing this, room by room, via flow rates on the manifold....... is just going to be wishful thinking afaic. £400 to assure you of excellent boiler longevity, and user comfort? Money very well spent IMHO. "This ain't no passive house baby!" edit: closer to £800 tbh with buffer and plumbing alterations, but I still would recommend this in a heartbeat.

☝️ 👌

Why not use cementitious self-levelling screed and have zero of the above? @nod what say you?

Punishable by a full 5 mins on the naughty step 👉 No probs, I'll cancel the cavalry

Are you intending to stand the first saleable property away from the existing connection for the farm and solar array? Is the plan / assumption to only be tethering the house you build for yourselves to that? I'd assume that connection has plenty of headroom for the second dwelling too. The DNO will need to be approached for this, as we can only procrastinate tbh, but I'd have thought there would be no issue with them digging down and splicing the new feed cable from the HV transformer to create the additional connection and supply cable for the immediate needs.

Anti-syphon devices are not for preventing back flow. A non return valve does that. Can you post some pics of the waste pipe plumbing and trap under the bath, and where you have accessed it to rod it through please? Baths also don't usually have P-traps.......odd that you say you have one? Again, a pic please

I'm curious as to how the higher profile deals with meeting the timber at the apex... Plus the fact this individual couldn't just go buy some black cement colouring.... 3/10 for effort, if I'm being generous, but as said above it prob keeps the rain out.

Somebody reported a post by accident here?

Agree to only use 16mm pipes here, but also accept that the different floor coverings will yield different performance / comfort characteristics, eg one will emit more w/m2 and the other less, so heat up times will differ from the set time to be at x temp at x time etc. This can be combatted by using smart self-learning stats per room / space, as these will decide how long a zone took to get to temp and then adjust (called setback) accordingly. I'd also recommend just clipping to the existing slab, and then screeding over with as little (suitable) product as you can get away with. There are self levelling cementitious screeds that can be laid at an inch thick or thereabouts quite reliably, but these (iirc) require a particular primer to provide the requisite 'purchase', so they don't part ways with the slab after being installed. If you use clip rails and fix straight down as I did here, then you will also have additional points of mechanical purchase via the clip rails. These I nailed down with a Spit Pulsa gas powered nail gun, firing 22mm masonry nails directly into solid concrete. £500 gun that paid for itself twice over on this one project, but you can hire also. These pipes were at 100mm oc, so that provokes the snail pattern, so the pipes only have to turn 90o vs serpentine where the pipe turns 180o at the end of every run; you need to not exceed the minimum bending radius of the pipe or it will kink! Prepare to have to install a 50L buffer tank (aka volumizer) for a bit of buffering for the boiler, as a lot of combis of that era won't want to modulate down to where you'd want them to be, if driving UFH directly.

Yup. The last one we quoted for a big project was £60k pa for the site agent, so we had the boxes ticked. Sent that to my QS who said, not going to be anywhere close enough, think again..... Ended up at £80k with all the trimmings. 2.5 years of that is hard for anyone to swallow, but for a proper managed and compliant site, these things cannot be avoided. We managed to value-engineer it a bit by appointing the role to a qualified chippy with other skills and qualities, so then the idea was to offset any 'thumb twiddling' time with programmed work that we had valuations in for. Just down to the level of GAF of the person you choose to employ I guess!

Yes, a WRAS approved motorised "ball valve" will suffice. I said motorised zone valve as I was up to me eyeballs again! I have seen them on the Telford thermal store (Tristor?) for cold mains top up of the F&E cistern, so assumed therefore that they must be ok? Just more of the principal of KISS etc

If you just want to be able to turn the cold mains off, in the event you left home and remembered it when arriving at the boarding lounge, then a WiFi fused spur connected to a normally open 2-port motorised valve will tick that box ✅.

Hi. The condensate CANNOT be run in copper as the discharge is acidic. All components / connections / pipe etc need to be plastic / PVC. You also need to make sure the condensate doesn’t discharge into a cast iron soil stack too. Condensate is cool / cold btw, no need for any heat consideration. 👌

Yup. Problem with white CT1 is a) it goes off-white (yellows) noticeably over time, and b) good luck trying to tool or finish that cosmetically! Sticks even to a wet finger 😣

Are we really looking at a cavity insulation layer of 240mm and then your air gap, or is that the actual depth of the cavity which means you cannot fully fill it? I’d pump this full of blown, bonded EPS beads, as with that product you can fully fill the entire cavity without issues of cold / damp / moisture bridging. Quick and simple to do in a day, depending on the qty / area obviously.

Same here. Haven’t screwed a WC down for prob 20+ years. CT1 nowadays; bed of clear under and sit the pan down into position. A load of baby wipes to clean the displaced goop until you have a nice ‘crevice’ and the CT1 is no longer visible. 48 hrs to cure, then whip around with a cosmetic bead of white silicone. When that gets grubby you peel it out and refresh. 👊

Yup, the sales patter and videos done by paid actors makes you drool for this..... I reckon you'd be regretting it in the first 2 hours or so. I just used to slash cut PIR so it had a wedge shape to it, then it would fit tight in between the timbers and leave a gap towards the front face. I'd just then foam between the timber and the cut edge of the PIR, let it cure, and trim back. Then just foil tape from PIR to timber back to PIR so zero infiltration can occur. As good as it's getting afaic.

Tell Knobby it’s game on 🥳✔️