Nickfromwales

You can check with their tech dept and see if they’ll allow you to introduce a 6mm aggregate to the mix. With A38 you can, and it’s mixed on site with a paddle mixer so you just add as you go. I can ask my screed guy for you if you like? I mentioned using A38 on a previous project ( walk on in 45 mins, and lay ceramic tiles in 4 hours !!! ) and he mentioned another product which he said was better again. Can’t remember the name of it for the life of me, sorry.

You’re decking the floor twice then though? It doesn’t get much simpler than alu plates, tbh, but if you’re DIY’ing then do what you feel most comfortable with. You using that ground and 1st floors? Or just 1st?

Engineering will tell you that the deflection is ‘fine’ which means it’s to the maximum that you will tolerate. That’s not a good standard to strive for in your own dwelling No probably about it. Been in houses that have been built both ways and the difference is massive, not slight. Folk should also remember that if they want to use alu spreader plates for UFH they need 400mm centres.

??.Have you asked for pozi joists @ 400mm centres instead of 600mm? Makes a HUGE difference in the bounce in the floors. If it was my house I’d also ask for extra strong-backs on the longest spans. Pennies in timber, priceless in results.

There will be plenty left to do, trust me. You'll just have started to hate the process by the time you've got to the 'nice bits'. Some like the journey.....others prefer the destination. Horses for each of those courses. Just sometimes the horse is only fit for the glue factory because it's too knackered at the end

If you buy one with an electronic brain vs hydro-mechanical, you can move the regen to 03:00 so it's done when you're fast asleep

This is just such a no-brainer. Watched a TF company put a 300m2 build up, including passive raft foundation, all to passive standards, in 31 days. AT score was 0.27 ACH. If you want the satisfaction of self-building, go for ICF ( just not Velox ffs ), but if you want your sanity and marriage in one piece go turnkey TF. By the time you've buggered off to choose your bathrooms / kitchens and floor coverings, the house will be most of the way up.

Then it will be a terrible benchmark and not apples for apples. Here people are mostly self / new building for themselves, developers cut any and every corner to make a fast buck. Even the "good" ones are not great. Premium is just the price the buyers paid for dwellings which were likely a load of shart.

The only reason I'd fit a hybrid basically, otherwise it would be a correctly sized and appropriately installed HP

Twin cylinder just keep soft water flowing during regeneration, whereas a single will give hard water through to the house whilst regenerating.

Yes, my thoughts exactly. Eg heat demand goes up to the point that CoP diminishes or flatlines, so it uses fossil to compensate. I'm just curious to know how comprehensive or 'clever' the controls are, where it stands with outdoor air temp vs internal demand and what-not. Time for some annoyingly long chats with the good people at Grant. Wish me luck.

It's such a relief that we have a father figure on here. Keeps us on the straight and narrow

Ah, yes it is. You got me lol. Also, an example of answering your own question then? Yes. Get your M&E coordinator to design everything to fit into the fabric of the build, have the steels etc pre drilled...... On my current clients MBC PH build, the in-house designers and I, plus the SE, did all this in advance. 300mm posi joists met 252mm steels, so no gap for 92mm ducts to go under ( above the ground floor ceilings ). I asked for the grade of the steel to be beefed up, and the profile reduced to 202mm. Job done. We now have 98mm under the steels which a) gives free run throughout the ground floor, and b) negated having any holes made ( bar 1x 117mm FW hole in 1x UB ). Plumbing / electrics / mist system / MVHR / and FW+WW all in without a single boxing in. Hopefully your TF company can work with you to do the same

This is an example of folk not involving an M&E early on in the build process. All of my projects have the steels Pre-drilled for MVHR and FW/WW etc and permissions in place for drilling through glulams. Can you ( have you thought to ) petition the SE to ask if you could have the steels penetrations done retrospectively? In other projects I have reduced the 92mm ducts to 25mm x 225mm rectangular ducts to get up inside the service cavities of an MBC TF and that negated a lot of unsightly boxing in. Don’t know if that can help you out with some of the runs, or maybe going from round to ‘oval’ ducts and mechanical 90o bends etc.

Very easy if you're dull enough to put it straight down onto a dry floor and to not put it where the lowest point is and systematically work the layers back up towards the high point. @BrianCork94 Tell this guy to put more leveller down and to do half the fall starting at the lowest point. 6mm or so over ~3m should not be noticeable.

To protect it against EVERYTHING lol. Including the unknown.

Make yourself a box out of OSB / PLY, fill the inside with bubble wrap, and slide that over the manifold to keep it in one piece.

He's a man after my own heart. I would deffo divert to a small buffer or LLH when in 'cooling mode' instead of having a big cold buffer. Should help to control potential condensation issues. I am looking at using 2x 3-port diverter valves to switch between devices per 'mode'.

Defrost cycle simply fires up the HP pump. only, and the water from the buffer is used "in reverse" eg it is then the HP which is 'heated' by the warmed water in the buffer. Pump flow ( direction ) stays the same, as confirmed above.

The use of hybrid HP's is to get you warm. I'm not talking about regular HP's so the argument / situations would be very different. The idea being you'd only be using the absolute minimum amount of fossil as possible, but have the opportunity to employ a HP for the shoulder months. When it gets baltic and a typical HP would then 'max out' without providing enough heat input, you employ a hybrid to get the best of both worlds; electricity based heating to a point where the SCoP is still sensible, and then fossil for when it is unavoidable. That gets homes off fossil only heating, so the CO2e will be minimised as much as is practical.

The controls / weather comp / when the oil or gas kicks in etc is one of the main topics I wish to discuss with their Tech Support guys, ( when I get 5 mins spare!! ). Hoping for a degree of synergy on that front. In terms of when the hybrid kicks in, that will be nothing to do with prices of energy? That will be decided for you eg when the house is cold and the HP cannot get the house temp up so the burner will kick in to supplement / take over. Cost will be what whatever they will be, as you will simply need it to do whatever it needs to do, whenever it needs to do it, in order to maintain the desired internal room temps. You won't really be able to able to strategize that much tbh, so probably important to oversize the HP to make sure it does as much as it can before burning any fuel.

I've been fitting their oil boilers for decades, never had a single failure. Very robust bits of kit. Am currently looking into their hybrid LPG and oil ASHP's for some clients builds which 'aren't quite there' in terms of airtightness / thermal detailing etc.

The tee is "equal" so flow from the HP pump can go to either the buffer, the UFH or both at differing potentials without any issue at all. A typical CH system h as multiple tee's all the wat through the arrangement, and no problems there that a bit of balancing doesn't put to bed.

With the 2 pipe buffer you can usually get away without the secondary circulation pump that would be required to get flow to the manifold pump. Less components and a more simplified install. I typically go 4 pipe with LLH’s and 2 pipe with buffer tanks. The arrangement you show offers both hydraulic separation and energy buffering, so I would run with exactly what you’ve drawn above. For the defrost, afaik, the check valve will not cause issue as I don’t believe the pump reverses flow for that (?) Anybody?

Just remember to sleeve the pipe when passing through structures with a cavity, sealing the open ends of the sleeve on the side which would allow any accumulated gas in the sleeve ( in the event of damage ) to escape to atmosphere or the ventilated space.