TerryE

The UFH manifolds in and pressure tested. It's coming along. Next step to plumb in my Willis heater. @jamiehamy Is this one next?

I do have to wonder how you are going to use your boiler. Sounds like you need a buffer tank to me. If you want your UFH to output roughly 1kW then you'll only want the slab a few degree's above target if you are heating over extended periods but don't want to cook. Have a read of both Jemery's and my blogs where we discuss the design issues.

We adopted a similar approach to Jeremy. Our two internal stacks terminate in AAVs. We already had a branch to the kitchen, so we extended this round to our gable and have a ventilation stack there. Our intent is to use an external AAV if the BIsnp OKs it, and even if he doesn't we might just end up having an accident after sign-off. If we replace the full stack, then we'll use a short one with an external AAV.

The other thing is as Jeremy says the noise Over 1m/s and its audible. The sound will start to carry at 1½m/2 and by 2, you are starting to get cavitation in the pipes which will literally wear them out: those vacuum bubbles imploding on fittings and pipe walls will systematically erode them.

@jamiehamy was there a reason for using a 32 mm MDPE supply instead of 25mm? Broadly the 25 MDPE pipe has the same internal diameter as 22 copper, and 32 MDPE as 28 copper. You aren't really supposed to expose MDPE to direct sunlight, so you'd normally go from MDPE to copper on entering the house. So another option would be to use a 32 MDPE to 28mm (copper) stop cock where the MDPE enters the house and then run your main riser backbone in copper and T the 22mm pipes directly off that. If you are a bit wary of working in 28mm copper then you can always use the Pegler Tectite fittings which look neat and are demountable if you need to do so. @Nickfromwales, any comments?

Simple Qs, but the answer is complicated. The first thing to establish is what your rough average heating requirement is. This depend of a buck of losses: through the walls, slab, roof, windows, air exchange losses. In a house build corrrectly to the 2013 Bregs, this should work out at maybe 5 kW. However houses as built by most of the major builders are far below this one average and clearly the earlier your house was built then in general the less energy effcient it will be and the more heat losses that you will need to balance. At the other extreme you've got super insulated houses like Jeremy's and mine which need less than 1kW input in the depths of winter. So my Q1 back to you is: how much heat do you need to supply as a base input to keep your house in balance. So if you need 5 kW, say, and you have 200m2 of UFH area then the floor will need to deliver ~25 W/m2 of heat into your lining space which requires the floor surface to be at roughly ambient + 4°C. For your house this might be more or less, but if it is much more than 10°C then you will have problems with hot spots. So you need to work out roughly what the ideal floor temperature should be for your demands. Clearly this will drop as the weather gets warmer since your heating demands drop. So now this is the circle that you've got to square. On the one hand if you pump water into the slab a lot hotter than this, then your controls system will end up on a roller coaster of heating the floor and waiting for it to dump heat and cool down again, but if you have the water demand temperature too low then the boiler will continually short-cycle, which is very inefficient and this really kills the life of the boiler. As Jeremy mentioned in passing, the only sensible way out of this is to have a decent lagged buffer tank. Your boiler reheats this buffer on on/off temperature thresholds so that each heating chunk is a sensible amount - - say 30-40 mins of continuous output at its optimum output setting to lift the buffer to 40°C say. Your UFH manifold / pump / mixer then blends this buffered hot water into the slab at ambient + 6-8°C if you want to sustain +4°C, say. The boiler then run for 30mins every 3 or so hours, and the UFH pump circulates pretty continuously, trickling just enough heat to keep the rooms comfortable..

Just remember that you need to protect the external vertical face of the EPS with a rodent-proof barrier. The last thing that you want is Rattus Norvegicus or even Tommy Titmouse setting up home in your EPS and starting a family there. We chose a perimeter slab path and an engineering brick plinth because this was zero maintenance for the life of the house, but others have used steel mesh and render.

Maybe so, but for the 3rd or f4th time, I will say: these jubilee clips aren't some generic ones: we bought these as part of an installation kit from a reputable Gas supplier. I agree that all sorts of comments are relevant to auto changover set-up, but having now read through the guidelines, LPG configurations are divided into three categories: Cylinder installations -- that is where you have a static storage vessel which is typically refilled on-site from a suppliers LPG tanker Multiple bottle installations Single bottle installations. The best practice for these three is different. Jan and I decided from the outset that we wanted a single bottle installation. And that's what we have. IMO, it doesn't make sense to say: I would have had a multiple bottle installation and then criticise the installation for not following multiple bottle best practice. There's a lot of good advice here but maybe we should somehow tag the various points as relating to either single bottle or multiple bottle installation and keep the two quite separate.

A good rule of thumb is that if the joist cross the wall and are resting on it, then its load-bearing, because it is -- bearing a load, that is.

This and you should have rebar reinforcing through the tongue back into the ringbeam. As J says, the cut-out method allows the tongue to be formed in the same pour as the slab itself. Yes you will get some degree of bridging because of reducing the EPS upstand at the doorsaw, but it you do the heat flow calcs, this is only a small number of W so long as you maintain some insulation thermal break. We used FoamGlas because I had some left over but it could even have been 25mm EPS. (We slated over ours.) The critical issue is not the absolute W, but that you don't want any surfaces in the door reveal getting below the dew point for the room and therefore getting condensation.

Congrats

Guys, as I said before: if you want to find who is correctly certificated then you can check with the Gas Safe registry by class and postcode. As to the supposed illegality of jubilee clips, as I said these came from a reputable dealer, and perhaps one of you better tell Calor that they are selling the same "illegal" fitting. Maybe this is why you should trust the registered professional.

Better consult the Lord High Executioner. I used 22/15/22s instead of 22elbows on the manifold loops and put the draincocks there. This is also for the pragmatic point that I can use this 15mm spigot as a fill point for pressure testing before the whole caboodle is complete. They can back siphon in pathological conditions, and you need to add some check valves on the branches to the DHW from the CW riser if you are concerned about this, but I would add that the DHW has to be potable in a modern pressurised system anyway, so there isn't any difference from the back flow risk from CW to CW tap.. Any taps or appliances where there is a risk of backflow should address this by design.

Jamie, for future reference you can get crossover fittings You also need to think about how you drain it down if you have to, so you might want to add some draincocks. IMO it's also nice to be able to isolate the entire hot or cold at the quarter turn of a valve and you can get decent full bore ballcock valve for this. But looking good

It doesn't work that way. Eventually you become a decrepit old fart like me and then its down hill all the way.

@Barney12, one of the hardest lessons that Jan and I had to learn is to accept that a build is going to take a lot longer than we initially planned. As a single self-builder you will have very little clout in making sure that trades will arrive on the date initially promised, and then when they do, it's a case of sods law and some other tradesman that you needed to complete before they could start is running late. The more that you crash the build timescales, the more stress you are going to have; the more its going to cost you; and the more compromises that you are going to have to make. Not good. You and your partner just need to ask yourself what the true cost financially and on your life is a 6 month slip going to make. An honest assessment. If the answer is that you aren't going to die in a ditch then I would suggest that you stretch the timescales. Add time contingency between the the key build phases. Then you are continually stressed to hell and having to reschedule trades. There are a lot of upsides to taking your time as well. In our case, there was a long lag whilst we got all of the planing and preconditions through the approval bureaucracy, then a flurry of activity in Oct / Nov 2015 when the slab, frame and windows went in. We didn't do boarding out and plastering until a year later, but in that time we could experience the space and in doing so we realised that we'd got things wrong, so we could shift a few internal walls, add another wetroom; shuffle upstairs room allocations. We also allowed the whole frame to stabilise and the slab to totally dry before the external stone skin went up and we laid the ground floor and boarded and plastered. Three months later we haven't got a single drying/settlement crack. Doing a self build is stressful enough as it is. Don't pile rocks on your back.

@JSHarris, Jeremy, I agree that there is a different sweet spot for professional plumbers who can have a high degree of confidence in the reliability of their joints, and this is also a case of time - money and the end customer might not be willing to pay. But @jamiehamy is a DIY installer, and I feel that decomposing the full down installation into separate sub-units and doing sub-unit testing is a sensible approach for him to consider as an option.

They use a rolling allocation: the team moves straight on from one job to the next. Our date ended slipping by 2 weeks.

Our TF manufacturer used a special to purpose air-tight OSB for the internal membrane and went to great lengths to address the vulnerabilities around the ends of joists, etc., and also contracted a guaranteed level of airtightness. Many of the high-end window installers (we used ecoHaus Internorm SW) make a particular emphasis of their installs being airtight as well. So it's a lot easier getting the airtightness sorted when the build technique is optimised for air tightness in the first place. Unfortunately, this isn't always possible, especially in the case of an upgrade to an existing property.

This test point issue does confuse me a little. I have a single pipe wending from a gas hob through a wall to a spigot where a gas bottle goes. The installer tests the pipe by sticking his pressure tester on the spigot end and thus tests the bits inside the house structure that are a safety issue, and then sticks the Propane flexible pipe on and uses his funny solution to look for leaks in the open air. Or he adds a tee and a test point, and does the test there? But how does he know that the test point isn't itself leaking when he closes it? -- Ah add another test point to test the test point, and before we know it (to misquote Terry Pratchett) we're test points all the way down. What I am really saying is that a test point makes sense to me in a conventional gas installation where you have one or more appliances permanently connected to a static supply or even an external static LPG tank and the engineer would be unable without it to test the integrity of the internal pipework for leaks. In this case we have a single pipe running through a wall with a gas hob on one end and a spigot for a gas cylinder on the other.

Nick as I said this isn't what the regs actually say, and also the IGEM (the Institute of Gas Engineers and Managers) also quite clearly states in its Technical Guidance on The LPG System that: [My italics] So who do I believe: you and Dave, or the professional body responsible for the guidelines? However I've already discussed the safety fastener and maybe I should have declined to show the photo before this was fitted. Ditto using the correct spigot on the gaps pipe and the wisdom of a second anchor near the end of the pipe. I can ask the guy to come back and do this extra work, but I can't criticise him for not fitting an extra valve at the wall if his own standards authority says that it's not necessary. Can I? XXX. Confused from Northampton.

@jamiehamy IIRC, 51°C exceeds Bregs. The TMVs aren't fitted with NRVs. But you won't get back flow through a TMV. (Have a read of my latest blog post). Use an O ring or washer. Where I disagree with Nick's approach here (did I just blaspheme, BTW) is the lack of a compression straight on his CW riser. I break all of my copper work into separate sub-assemblies that I can make up on the bench and isolate for pressure testing before putting them into position. e.g. using an end stop instead of the TMV output. I also had my draincocks on tails so these tails can double as the fill points for pressure testing before final assembly. Doing this has three major advantages: No hot soldering in a confined cupboard in a timber framed building. You can test each sub-assembly on the bench (or the floor) before you put it in position. Unless you are Nick, you will find leaks and need to rework. You can flush out any residual flux and crap from the sub-assembly before you put it into position.

@oranjeboom, my main concern about that extra 0.02 on the slab U value is that it might entail you having to raise your FFL by 100mm or whatever, so you might loose 10cm of room height, say, for two shades of bugger all difference on your actual heating bills. How you achieve your airtighness (for example) is going to be far more significant in your overall heat balance.

Clive's link only describes the BS for flexible connectors and the only one which seems to apply to this is BS3212: 1991 Type 1. Dave your list is unreferenced, and as you say; you aren't a gas engineer. Many of your points might be valid, but how can I confirm this? I've tried doing searches on Google and gone down maybe twenty pages of results, all either not relevant or behind logon walls. Going back to the BRegs, Part J sections 5.19 and 5.20 apply and once we've added a securing chain as you suggest we comply with these. And in fact our gas engineer did tell us that we would need to fit one before the building inspection. Part J section 3.1 also says that all gas works must be a carried out by and certified by a competent person, and this is effectively defined by the person being current with the appropriate certificates and being on the GasSafe register. We also comply with this, though I note Dave's view about the actual competence of my gas engineer. The installation also has to be carried out in compliance with the Gas Safety (Installations and Use) Regulations. I did find the referenced HSE document: Approved Code of Practice and guidance Safe installation and use of gas systems and appliances, Gas Safety (Installation and Use) Regulations 1998 which discusses qualified persons, correct installation, testing, etc., but nowhere does it state that a separate test point is mandatory, for example. And the regulation itself only states that testing must be carried out. I also found a copy of the newer draft 2013 fourth edition does stipulate in guidance 9(1) "Whenever a new gas supply is made available for use in premises, an emergency control should also be provided". And 9(2) states "The emergency control can operate by a key, lever or hand-wheel which should be securely attached to the operating spindle". [My italics]. Yes it does go on to say that if a key or lever is used then it should be a quarter turn, but in the case of a single cylinder surely the hand wheel on the cylinder itself complies with this requirement. I agree that it doesn't in the case of a two cylinder with automated change-over setup, but as I said, we only have a single cylinder. There is a material difference between views of best practice, compliance and non-compliance. I will be more than happy to get the engineer back to do remedial work where we are in fact non-compliant. But interpretations on best practice are quite another issue. As I said the equipment was supplied by one of the main LPG suppliers locally and installed by a qualified engineer. It meets our needs and without firm references, I am not sure what I can go back to him with. I am not the expert here.

In our case if the gas runs out in the middle of the night, we'll just use the induction hob until I get around to changing it, so this isn't relevant to us. I am at a total loss as to why you need high pressure hose for ~20 mbar pressure. In the event that the regulator failed catastrophically then the last thing that I'd want is one of my gas burners going up to 1 bar say and blasting a gas flame 20 ft into the kitchen. Far better that the pipe outside fails. The thing about a boat is that it has this gas-tight LPG collector called a hull, and gas leaks in there are a severe safety issue. Maybe we'll have to get Jeremy and Dave hooked up with our local LPG dealer who provided the hose and fittings. As I said guys, can anyone actually point us to where the regulations on this are in writing and publicly accessible, rather than behind some logon wall only accessible to Gas engineers?