MortarThePoint

Plain inhibitor (no antifreeze) is much more dilute and cost effective than with antifreeze but obviously wouldn't add any winter protection https://fernox.com/product/protector-f1-500ml/ https://www.screwfix.com/p/fernox-f1-protector-central-heating-inhibitor-500ml/342pp

Pipes full of water and house roof on with proper windows half in (poly windows elsewhere). It is the conventional wisdom to do a wet pressure test before the pour and to leave it pressurised during the poor. The pressure test could identify if the pipe was damaged as laid or at another point prior to concrete which you could identify and rectify before pour. Agree you are unlikely to do anything during pour. But it's nice piece of mind to still have pressure after the pour. Finally, a pressurised pipe will better resist damage from being squashed. 6bar of pressure is around 100PSI so can resist the full weight of a person across an area of just 12mm x 100mm which is around a foot's width. Yes the pipe is strong, but may as well help it. Here I am convinced water is a better choice than air as air is compressible and water not. That means that air would only ever push back with the system pressure whereas water could momentarily increase the pressure, and locally due to inertia. The inertia of the water would resist impacts much better than air would. Agreed, but when inexperienced it is often about minimising unquantified risks. You don't have the experience to know it will be fine anyway so you do what you can to give yourself the best chance.

I've used 16mm pipe with an ID=12mm so 113ml per metre. My total system volume is 180l, so I'd need 45l of this stuff or 9bottles at £202. Expensive but less than burst pipes. Do most people have antifreeze/inhibitor in their UFH systems? I know inhibitor is a must for radiator systems, but don't know about UFH. @Nickfromwales do you normally install inhibitor antifreeze in UFH?

Is there any trick as to how to add it to the system. I filled my UFH directly from mains so don't have a pump box. Might have to get a small water pump (like for fountains) as haven't plumbed up any proper water pumps yet (system is only UFH pipes and manifolds so far). I presume this is what you used: https://www.screwfix.com/p/flomasta-0623-concentrated-central-heating-inhibited-antifreeze-5ltr/4409r

What antifreeze/inhibitor did you use? Air bubbles add a lot to the noise of a system, is it possible that when you topped up the system you significantly reduced the amount of air in the system?

I have a compressor so could threoretically blow out the water, but I'd rather not I think.

I have UFH pipes installed in screed and am unlikely to have any heat source available before the temperature starts to get low over winter. Do most people just have plain water in their UFH or is antifreeze usually added? Has anyone else gone through winter with UFH in place but unheated? Another consideration is that once I eventually have the ASHP installed, I would like to be able to use it to cool the UFH during the summer. I'm sure it would be set up to keep the water above freezing, but a failure mode is to over call the water which could burst pipes.

Wow that must have given a very good U-value as you pretty much have a continuous ~300mm thick layer of foam insulation. I can see Posi-joists work really well with insulation like that.

I can imagine an unfortunate time gap opening up between the two schemes for new builds though unfortunately. I have spoken to installers that loath the MCS/RHI scheme and say how much it jacks up the cost. There's the danger the new scheme will just be the same nightmare. One installer has said he's considered abandoning doing ASHP installations because of the MCS.

I don't know if there has been much confirmation, but looks like the new £5,000 scheme is not available to new builds: "The grant won't, however, be available to those in social housing and new-build properties at launch." https://www.moneysavingexpert.com/news/2021/10/government-to-offer-p5-000-grant-per-household-to-help-them-repl/ This is bad news for anyone worried about the RHI deadline next March.

Hmm, now feeling less smug about my 2m spirit level.

I'll be doing that for architrave and skirting for any tiled/wood/laminate areas, but I can see the benefits of door lining going in before plastering. Maybe not before plasterboard though I guess. I'll probably loose fit when putting up the MF and slide it out for plaster boarding, before then finally fitting before plastering.

No MVHR. Probably want a gap of around 3 - 5mm for carpet clearance. Looks like I'm OK with not having to trim the verticals.

Thanks. I've measure the vertical and their internal dimension is 2006mm which for a 1981mm door is 25mm over. I guess that leaves 3mm air gap at the top, 3mm at the bottom and 19mm for flooring. Does that sound about right for carpet plus underlay?

Should door lining kits be fitted so that the bottom of the verticals rests on screed or should a gap be left for flooring? I can imagine it may depend on flooring choice (tiles vs carpet). Sorry for the basic nature of the question, but there is a first time for everything.

So you've still got a screed or something left to lay after this photo was taken?

Thanks. Looks like they have glued and screwed the door liner to the metal studs so should have a solid connection. I can't see any signs of packers so perhaps the metal frame reveal is 2 or 3 mm larger than the door liner. A couple of questions: Why don't the vertical bits of the door liner go down to the floor? Why the gap above the top of the door liner?

Thanks very handy. They appear to be using 10mm extra for timber studs so: 838 + 2*28 + 10 = 904 Given metal frame is much more accurate than timber studs I'm tempted to just build the kit into the metal frame studs as I go, so effectively reducing that 10mm extra to zero. If you could measure with the laser that would be awesome as MF may be tighter reveals than timber studs.

@Conor sorry to call you out, but do you know what your contractors did for this? Did they make the door reveals tight to the lining kit? I guess ultimately, what size gap for what size door?

I'm wondering why not to build the door reveal with the door lining kit inside all in one go. If you prime the wood of the liner kit you can plaster skim afterwards and if you're taping an jointing it wouldn't matter anyway.

What gap did you leave between the c-studs of the reveal for what size door?

If so inclined, could add floor channel sleeving the C-stud at the reveal as well as bending the bottom floor channel 300mm up:

I'm establishing various door openings in metal frame and wondered if anyone recommended any particular door liner kit as being good. They don't appear to fully standardise on the thickness of the timber and that affects the size of the reveals to be left in the metal frame stud walls. There do however appear to be lots that are 32mm nominal which equates to a finished 27mm. There appear to be thicker ones for fire rating purposes. A 70mm stud with plasterboard either side works out as 100mm, so it's the 115mm nominal / 106mm actual lining I'll want I expect. Is the extra 11mm (12.5mm plasterboard) or 6mm (15mm plasterboard) is to allow for plaster skim? You have to reinforce the C-studs next to a door with timber and there are two ways of doing this. Either tuck a piece of timber into the C-stud or move the stud away from the reveal to have it on the reveal side. Which is best for a solid job? How much wiggle room do people leave with MF studs? One general guide copied below suggests 10mm both sides but that seems excessive for MF. I was planning to go with 5mm each side so a reveal width of 830mm. 10mm (wriggle room) + 28mm (lining) + 762mm (door)+ 28mm (lining)+ 10mm (wriggle room) = 838mm (call it 840mm) [3] https://www.selcobw.com/products/doors-windows-stairs/doors/door-frames/door-lining-sawn-metal-stud-32-x-115mm-nom-pefc https://www.wonkeedonkeexljoinery.co.uk/fitting-a-new-door/how-to-fit-an-internal-door-frame/ [3] https://www.juliancassell.com/2528/interior-door-frames

I don' like salmon so works for me ? . You also get to watch you food go round in a rotary one like a gameshow prize. Joking aside, the extra space does make good sense if not too much of a premium. If it adds a large premium then how often does the extra space help. If you're building to sell then bells and whistles in the kitchen can make up for a corners cut everywhere else it sometimes seems. Like awful cars with good radios with connectivity.

Some designers justify increased prices with increased functionality normally accompanied by increased complexity. I don't need my microwave to be online, I need fast hot food. We won't be going integrated for the likes of a microwave. I'm not a fan of the integrated look and we have space on the counter. My brother went integrated and the appliance he chose had a £200 surround so he had a local fabricator make a stainless one for £60. Looks very slick.