Nickfromwales

I am the principal M&E coordinator on that project, so the system is being installed to my spec / guidance. MBC have many of these under their belts, and they work fine for heating / cooling etc ‘out of the box’, and typically go in at 200mm centres in a serpentine layout unless someone specified differently ( for a reason ). Deviation of course causes uplift in prices For this project I am using very particular equipment, and also integrating cooling via slab + MVHR, so have done calcs which are unique to this sizeable ( 400m2 ) dwelling. One size does not fit all, so please do not focus too much on this detail for your build as it may not be relevant.

How are you heating yours? ASHP?

Yes, exactly why I’m doing it !!

The 3D cubes can be chopped and made to work, but second solution is far simpler of course.

Crossed with my reply. That’s the ticket !! ??

Surely that picks apart and you can create the corner with the parts? Remove the border pieces and construct with the square. Prob needs a Dremel / other to break the squares ‘apart’.

I’ve never laid serpentine in any of my installations. Reverse / inverted is the best layout afaic and allows for much better heat dispersion and almost zero 180o ‘U’-turns, which are not great for enhancing flow rates. Also, if installing on anything less than 200mm centres, inverted is the only layout that allows for tightly packing in the pipes. On my current project, an MBC TF passive raft, the pipes are going in at 100mm centres to maximise water volume in the system ( to aid the operation of the ASHP + cooling ) and that can only go in via inverted at that distance apart. If going DIY then serpentine may look simpler, but inverted really is a doddle to lay, me imho easier than serpentine as you’ve not got to perform so many ‘U’-turns ( which are difficult / easier to kink the pipe with when performing scores of them with each loop ? ).

Hi. With such low flow temps ( as associated with these types of emitter ) I really doubt that you’ll get any issues whatsoever. I would run the pipes under the stairs though, instead of dog-legging through the plant corridor. Come up into the manifold from behind, or even relocate the manifold under the stairs to free up some more space there if there’s nothing else under the stairs. That would be better than nothing, but again I think probably unnecessary with such very low flow temps.

Make sure you don’t go off the straight line when laying or it’ll quilt up and then you’re into cutting out sections and patching. It’s quite hard to spot too, so keep checking back on the previous runs to ensure they’ve stayed down. A cheap 9” roller will help to lay it smoothly. FWIW, I’ve laid Christ-knows how many floors without Ditra / other and not lost any of them ever. My golden rule is prepping and never laying onto a dry / dusty / contaminated subfloor. I have seen others lay directly onto screed which has been too long on site / not laid quick enough and the tiles + adhesive + top skin of screed has come up one one big sandwich. Screed needs to be sound, prepped properly, and bingo. I’ve only ever used a mat over unknown sub base or liquid screeds.

It’s 100% sound. Chill out. The pressure fluctuations are just relative to changes in ambient temp. Go drink more beer. ?

Is this in screed or a passive raft / slab?

Nope. It’ll get in those just fine. ? Do you have a loop above the manifold?

Ok, firstly if it’s a liquid screed, both ends of any sleeve would need to be sealed to stop them simply filling up entirely. Your pics show open ended sleeves, both ends, so these will fill with screed and do the square root of FA. If you have rooms very far from the manifold, it helps to insulate the flow pipe so as to preserve the premium temp water so it arrives at the zone it serves at as close to the TMV ‘injection temperature’ as possible. I see a lot of poor performing installs where the furthest zones really drag behind the others, some don’t get up to temp at all as all the heat has ‘gone’ by the time it arrives at its target area. I always shutter around the UFH pipes where they congregate at the manifold location, which allows for the pipes to be dressed in and bent / straightened to line up with the manifold nicely. Where necessary I also insulate the first 1-2m or more of each flow pipes that is serving a zone that is not local to the manifold. House / installation size / slab vs screed etc are all factors I consider when determining whether this is required tbh. 9mm wall insulation is sufficient, but again needs to be sealed and ‘waterproof’ so the liquid screed doesn’t get inside. As far as just using a sleeve, it is a good idea in terms of protecting the pipe where it may be damaged where it’s above floor level, but your proposals for expansion via use of bits of sleeve ‘here and there’ is of zero practical use afaic. Take the advice of the guys laying the screed, as this advice differs with different types / thickness / etc and each job needs to be advised on its own merits.

If you already have an oil tank and have retrospectively upgraded your dwelling, then it seems sensible, eg if the insulation and heat emitters aren’t quite ‘there’ and an ASHP alone will struggle wintertime. Otherwise I’d not really go forward one. The cost is high, but it’s a cheap be box external unit solution that is quite neat and effective imho. That means you can use the HP for the brunt of the heating and just have oil kick in only when absolutely necessary.

This kind of thing

Who priced you at that amount?

I’m ill….. ?

6 and two 3’s. More insulation, less losses, lower flow temp > better CoP from HP. There’s only so high a flow temp you can run at the end of the day. Look at how well electric UTH works in a bathroom

Someone’s got to pay for all the new cups. ✌️

Zero issues. I’m about to do the same in triple digits of M2 in screed and over existing ( insulated ) slabs. I absolutely will not be using the castellated trays, as I do not want the air gaps that are underneath. This faux pas is due to yet another architect who screamed “eco credentials” but failed to back that claim up. Otherwise the slabs would have been 75mm thicker and the UFH pipes encapsulated in the concrete. Can you not do this?

Just seen the pic. Mesh, deffo.

Is the screed in now? If so my apologies, just foam it!! Thought this was going into the screed and was to reinforce the screed at that point so it doesn’t fracture and just float there. Grafting and typing as usual.

Chicken dinner.

Fail to prepare, prepare to fail. Mesh.

I would get a Hybrid ( oil uplift ) ASHP and condense the solution. That would allow ASHP only where minimal heating is required, but then burn oil to fortify when, and only when, necessary. The 70m2 Will likely need 4 loops, as you’ll want to be well under 100m for each individual loop length to maximise even heat output across the whole area. Pipe size and centres ( distance from pipe to pipe ) will be dictated by the system you choose, but given this is retrofit which is incredibly tricky to get right I would 100% be using an overly system. If height is an issue, recess battens to accept 22mm P5 and finish them flush with the joist tops. Then I would skin the whole floor with 9mm ply glued and screwed for integrity. Then fit your overlay system on top of that with as much insulation in the build up as possible. Forget “thermal mass” you just want the heat getting to the room as directly as possible. Minimum 100L buffer tank, because of oil / ASHP, but if both they will need to become a multiple coil thermal store to hydraulically separate the different systems to suit. This will only give you a slightly better emitter, but at a cost. I would buy insulation not screed. Finally, draught-proofing the subfloor will be your biggest return, more so than insulation. Use foam a plenty, run the 9mm ply 8mm short of the external walls and then fully foam the perimeter. This will pay huge dividends.