Nickfromwales

I'm doing 100mm centres as standard these days as it's much better to have the additional cross sectional area for heat transfer, plus it increases the water volume in the system which helps mitigate against requirements for larger buffer tanks with HP's. If this is going into a screed, I'd say a minimum of 150mm centres. The No.1 suicide mission with UFH is to not install the pipe in the floor correctly / fit for purpose. A quick google suggests that 18mm pipe is from PolyPipe, so I assume the plumber would get the design FOC from his merchants!! You asking how many loops there should be etc says there is not a design at present? I would want to see evidence of the requirement, for the heat loss of the room, being more than adequately met by the system. Do not accept anything less. Also ask if the UFH will run independently, eg away from the rads, as this can provoke a requirement for a buffer to stave off short-cycling of the heat source ( boiler in this case ). It's usually in the boiler manufacturers installation guidelines to mitigate against this by design. The reverse / inverted method of laying ( above ) also gives considerably less resistance to the flow of water. Serpentine gives you a barrow-load of 180 turns where the water must continuously completely change direction which is not great. Plus if you google some heat signature images of the two layouts, you'll see the serpentine has a warm side and a cool side, eg where the heat diminishes from the flow to the return. Reverse / inverted does not suffer this way, and this is quite significant in a system where the pipe is in screed vs slab. Challenge your plumber, as you are the customer and it's your home and your money being spent in it. Use the Heat Pump / future proofing as your "angle" if you need to 'convince them' that this needs doing.

The water will pressurise both sides equally as they are made common by the pipe joining both manifolds Are the white caps all fully open? Same for flow gauges? Where did you pressurise? On the drain point at the end of the lower rail, using the top as the vent?

That’s not for us to say It’s your BCO who may fail it, so pass the onus on to the builder VIA EMAIL and state that “on his head be it should it not be passed”. Make sure he knows you will not be footing the bill for any such subsequent alterations to satisfy BCO.

Do you understand why this gap is a requirement? It is so that ground settlement / movement ( heave ) etc never affect the pipe. Pipes set in without have sheered in half because this has not been observed. It has zero to do with the functionality of the pipe, this is to ENSURE its longevity. Tell the builder this, and tell him to rectify.

Illbruck foam for the 50mm void, check different types for suitability. The website is quite helpful. Use cement backer board eg 12.5mm Hardi / similar as the closure plate.

Go for the Dwr Cymru option IMO. You are not going to benefit from any of the above suggestions with a gravity DHW system

Agreed. Pointless if the deck is not exposed to the elements.

Yes, the over painting is to stop standing rainwater from getting into the joints and, trust me, they swell up soon enough. It’s only when people put a straight edge down do they realise how much swelling has occurred. Prevention will always be better than cure

Yup. Keep the 8bsr incoming and take outside taps off direct, reduce to 5bar and pick up WC’s and cold fed appliances, and then have the house at 3.5bar balanced. Are you fitting an UVC or a combi? Other?

No, it’s not. It’s a recommendation for extending the amount of time an installed deck can resist the elements. Specifically aimed at TF’s where the deck boards MUST be installed before the second lift can go on. As above.

Why? Does it say “Do not use this glue after purchase”? Been using it for decades and I won’t use anything else. D4 PU glue is exceptionally good stuff. If it’s summertime or a spell of bone dry sunny weather, I use a fine mist of water or a wet sponge to prep the to-be-glued surfaces / areas as PU is moisture cure and it behaves completely differently when given the required moisture ( there is of course moisture in the air, but it doesn’t get to the core of the glue so that suffers ‘pockets’, air bubbles that offer nothing in terms of gap filling or purchase ). Regardless, you’d see excess if PU glue had been used.

You can use a cement substitute such as Ardex A38. We use that in screeds to get on them in as little as 4 hours. There are others out there. I’ll message my screed guy and see what he recommends.

….but are advantages in not allowing you to cheap out and blow yourself into the next borough

Impey do similar, connecting to either 40 - 50 or 110mm pipe.

It's only linear on the tray side, the trap dos not go linear, it's just a normal round trap so you only need to do as @Mr Punter says.

A can of worms if you want to break into that space tbh. Is this extra space super important / necessary?

Yup. Twisting action rather than linear strokes etc to avoid such damage.

They basically want to avoid a situation where you have a compartment that can fill with gas, mix with air, and go ka-boom. You cannot run a gas pipe up a wall which is random dot n dabbed, but you can do that if the gas pipe is fully encapsulated in the dab from floor to ceiling. The point being, any puncture ( nail / screw / drill ) would only result in gas being discharged into the habitable space where it is assumed the inhabitants would smell it and realise there was a leak. For any other spaces or compartments where your nose would not be sniffing about, it's no-can-do. I'd argue that pouring grout ( self levelling compound etc ) down that 100mm duct after pulling the Trac pipe through would satisfy that requirement, but then they'd ask you to prove that every inch of the pipe had been successfully encapsulated. Bit tricky that one. I'd check though, as the void is ventilated so it's a bone of contention.

What is the max distance from wall to wall, where you can tamp the concrete with a timber beam?

Jesus. Ouch x 20. However, we may have found somewhere for the 2024 Buildhub volleyball championships.

Let’s see what the OP says will be the plan for the pool and then we can properly rip into him lol. ?

Could you elaborate re the water source?

Unless even poorly covered ( with a building of sorts ) then the expense will be eye-watering to keep this warm, forget hot. Ouch. My advice would be about 15kW of solar thermal dedicated to just this, with excess diverted into the domestic hot water ( DHW ) cylinder, so at least it’ll have the chill off it for most of the year. Heating during the colder parts of the year would need a direct ‘pool’ ASHP. Did I say ouch?

Hi and welcome to the forum. From what you’re saying here, and above, you may already have the horse and the cart the wrong way ‘round MVHR cannot be ‘on the table’ if the intention is to go for air tightness that is excellent. You’ll choke on your own fumes without MVHR, for one, plus to be “green” or “eco” ( terms often used very loosely, and more often with a complete lack of understanding of what that is supposed to deliver to you in this reasonably unique build ) you will 100% need to be actively recovering waste heat for re-introduction through the MVHR system! Building control will demand your as built air tightness ( ventilation / infiltration ) results to be sure you have adequate numbers of air changes per hour. If all the above is known, how do you propose to meet those requirements? Make the house AT and then fit loads of trickle vents? ?. All these questions need firm and robust answers BEFORE pressing ANY more buttons. I’m currently providing M&E for such a dwelling ( pool etc ) and the design work was enormous. The pool hall will need its own envelope as the dehumidification and heat recovery system typically runs at a slight negative pressure to preserve the build fabric, therefore it should not be able to ‘share’ the air volume of the residential section of the dwelling. Forget recovering heat from the pool hall, as every ounce of that will be absolutely needed to maintain the temps in the pool hall!! How big is the pool? Is it a pre-fab that you are “dressing” into the house Lots and lots of things here will impact on the others, so measure twice cut once ?

Hi. If space is at that much of a premium you can get an inverter which can be mounted outdoors, with just the ancillary equipment indoors ( isolators etc ) which may solve the issue. Or go for panel mounted individual ‘micro inverters’ which will just require a controller.