Nickfromwales

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.

Agreed. Which is why I say he should sample, at the joist tops, and if even a whiff of glue additional screws should seal the deal. Without samples, we don't know if the boards are glued or not. If they are, but it's minimal, the deck will have taken to the top chord. Attempting to part them would be a train wreck as the natural timber will split away and never seat back down evenly. The retro-added glue would just fill the voids and jack the floor up having the opposite to desired effect. Sample time is now, eg before any more advice is possible.

It'll be reasonably unique to each instance. System volume, pipe centres, actuators vs no actuators and so on. 100L should more than suffice as a one-size-fits-all solution tbh, but it's then down to whether it's deployed as a 'thermal store' or an 'energy buffer'.

Yes, it can be a double-edged sword. You need to pull this guy to one side, and have a quiet chat away from the build so he takes you a little more seriously. He will likely be a little more humble then too. In terms of moving forward, you now need a solid deck and nothing more really, so options need bringing to the table. IMHO you have only one option at this stage, and that is to get the builder to screw these boards down, 5 screws per 600mm joist line with them starting and finishing 50mm away from the tongues / grooves. You need to stipulate to this chap that the screws need to be JUST pulled just under flush with the top surface of the boards and not smashed through thus losing all purchase. Explain if this is done, and the floor can be walked on without squeaks etc, and he carries this out meticulously, you will be willing to settle on that middle ground. Explain to him calmly, that if that detail is not executed to the letter ( word ) then he will become responsible for removing the walls and floors and starting over again, or paying for someone else to do so after he has been asked to leave. The bar needs to be set ( or reset ) before this guy does ANY more work for you. Next. It is YOUR responsibility to make sure any 'old correspondence' is dusted off and reiterated. Every inch you give = a mile away from what you expect. Expect nothing, assume less, reiterate everything and check, check and check again.

I think you lost me at "Complete......" tbh

Ok. Time for a reality check……. Has the builder said that a glue of whatever type had been used? If he says yes, then get a 100mm hole saw and sample 4 areas ACROSS joists. Remove the pilot after the hole has been started and then you won’t penetrate the top chord of the joist. If the discs of board come loose and lift out then his bluff is called. Start there. Don’t bend and tell them you want to know without any shadow of a bout that “a glue” has indeed been used. The part that stinks the most here is the fact that the builder has said that the floor will lift!! That tells me no glue whatsoever has been used because if it had you would NOT lift that floor 1mm. Stinks of no glue to me. Call it, and get the deck samples across the pozi’s and don’t accept any more BS.

Complete and total nonsense, sorry. Please don’t give such non-comprehensive replies as it’s extremely unhelpful. Allowing for an install with both a high, and a low level cyl stat, the ASHP can be made to kick in during shower number 2. The return water temp would be higher so the HP recovery would be higher / faster. Something to consider. With PV or an E7/10 boost the tank could be heated to a premium temperature above the normal capacity @55oC. Something else to consider. Direct electric heating via the immersion ‘could’ be strategically directed purely for times where DHW was most needed. It ( the immersion(s) ) can also be used for delivering extra DHW at times of duress, which I call “guest mode” on my installs. Occupants go up to the cylinder and hit a 30 / 60 / 120 min immersion boost switch accordingly. If done an hour before duress the tank temp ( and therefore it’s sustain ) can be elevated significantly thus increasing your lower temp x 300L @ 55oC capacity to a much higher capacity in the same size cylinder. Something else to consider. People do a funny thing after showering, it’s called drying off, squirting on sweet smelling products, etc etc. They also shower typically at 38oC. Therefore that needs to be considered in the calculations for the time needed for the cylinder to recover between showers / bathing. People do a funny thing after getting in the bath too. They get into it. And then they stay there for a while. A “couple” could easily manage with a 210L UVC with some very basic disciplines. A lot of things can be taken into consideration when sizing a cylinder, and stating all those things makes for a comprehensive reply.

If it’s not made its way out there, they’ve been more than conservative with the glue for sure. It’s nigh on impossible NOT to get that displacement. If not evident, time to get proof.