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Your architect is dim, that's not how you work UFH. Installer is worse he should have corrected him. Long and slow is best for all heating types with a heat pump, especially UFH. So if you have WC mode enabled, you run so the thermostat do nothing much, use them as temperature protection. So I would wind the room thermostat (s) up to say 23, and leave the heating to sort it's self out for 24 hrs. If the whole house is hotter than you want the WC curve needs to be adjusted down. If individual rooms are hotter or colder the UFH loops need to be adjusted, more flow is hotter, less flow is cooler. But the heat geek guy should be advising all this. Then once set the heat pump should manage itself.

Correct. In effect from 15th June 2022.

No we didn’t put one in our previous Think 22

Well no the caravan wasn't insulated enough but you get what you get - 25mm polystyrene between a metal skin and vinyl coated hardboard. For a 12 month stay it's not worth overcladding the outside (ruining any resale) and it's small enough inside already. So yes you have to suck up the extra cost of using electric heaters. As for a 4x4m shed - luxury! SWHMBO has put up with a 6' x 4' with washing machine and tumble dryer and a small freezer balanced across them. This is a building plot not a sports field. What with a sloping site needing to take a 100m2 footprint house plus scaffold space, a 36' x 12' static, two 20' containers with our stuff in them not to mention two cars which can't be left on the single width track outside; add materials and contractors vans.... As for mud - don't have any! Wish! We did have stone laid but hey as soon as a machine gets digging during wet weather I defy anyone to say their site stayed clean. Just taking the machine from excavation to low loader spreads mud across the access let alone moving around the site. All that lovely stone laid under the sun disappears under a coating of glutinous brown clay that sticks to everything. It's then you find out why you kept all those offcuts of carpet in the loft of the previous house - told you they'd be useful! Throwaway door mats - the latest thing. I wouldn't say these are negative views, just saying as it is. If you can't manage a bit of discomfort (or even the occasional "why the f... did we start this" screaming match) then self building is probably not your thing. Go buy a nice house already done for you. With a clean driveway.

weed membrane will do fine if you have some around. FYI The random fibres type is better than the woven in keeping everything out but it will be marginal for your circumstances.

Inconclusive. It was definitely the heat pump coming on, even though neither heat nor tank were programmed to run at the times it was happening (random Monday mornings), and none of the room stats were calling for heat. It's only happened once more since I reported the problem, and not since I put all the room stats into frost protection mode, so I may have to wait until next winter to see if it's still an issue.

perforated drain pipe there is posh stuff that allows precise flow, and there is cheap stuff that is tricky to get exact. wrap it with geomembrane so that roots and silt don't get into the pipe, then surround in gravel.

@garrymartin thanks so much!

You use the @ sign in your reply, and then the name of the person. As you start to type the name, a popup box will appear and you can select the person you want to respond to. So @Cookie, you're welcome! 😉

Sorry GarryMartin I wish I could figure out how to reply direct! Thank you so much, that's much more clear. Much appreciated.

If you can enclose it even better. The worst thing in the winter is opening the door and all the warm air rushes out. At least an open porch let's you strip the wet stuff and get the boots off, for a quick dive through the door.

Tell her the money saved living in a caravan will pay for a nice kitchen 🤷‍♂️

I have read somewhere [probably here!] that a shed porch makes sense. IE 6x8 shed with front and back door, back door leading to caravan door. plenty of hanging space for dirty clothes on, when taking of before entering caravan.

these are what we are using https://www.bpcventilation.com/panasonic-fan-coil-unit

If you’re going for the on site caravan option, and thus saving £thousands, maybes suggest, especially during winter months, a regular night away in a hotel, even an inexpensive Premier Inn. If scheduled ahead will give something for her to look forward and will do you the world of good to get away for a night and rest the aching body. Would also suggest, if your site allows, sectioning off the site from the caravan and spending just a few quid making it much more homely and more of caravan holiday home as opposed to a caravan on a building site . Even a bit of turf or whatever, some temp fencing or whatever. is there an option to do a detached garage first that you could in some way even if for dry storage or a temp shower etc.

when did this come into the regs? i didn't put one in for a site approved for BR's in 2021, completed this year.

Yes You will need it in and working for sign off

@Nickfromwales I'd settled on PE-RT / AL / PE-RT in my notes but this thread had me questioning myself again! Thanks for the clarification.

Pert (alu) for me, and just looked at the last invoice from UFHTD Ltd and that's what's on there. Not sure where I've mentioned PEX, but I have used both over the years. FYI, Pert Alu on every job nowadays. Just bombproof stuff tbf.

That's my understanding - EV charge point required. The only time you could install ducting or cabling instead is if you can prove the total cost would be in excess of £3600 as I read the regulations.

My top tip. Do NOT fit an accessible fan isolator in a rental. I have known tenants turn them off because they are noisy then complain about the condensation. I do not believe they are legally necessary (I have asked several times for someone to point me to the reg that says you must fit one and nobody has) but if you really feel you need to fit one, put it up in the loft close to that loft hatch. Check how air will get into the room to replace what is extracted, you may need to plane a bit off the bottom of the door for instance.

Greenwood CV2GIP, low background ventilation, easy setup, smart boost when humidity rate of rise is above a given threshold - almost silent. Mounted in ceiling and duct away, if that's easiest. Pulls about 2Wh electric. Normally get them on eBay cheap enough.

Hi my name is Chris and just completed a big renovation project (second one). Looking forward to get some advice on a few areas. Looks like a great forum! Wish I had found it earlier! Chris

It's the other way round. We have this exact setup working at the moment with 7 fancoils and UFH coil. We have the ASHP setup (we use Home Assistant to automate everything) to provide cooling 2c above the current dewpoint running 24x7. Dont need it for DHW as eddi and solar more than takes care of that. The fancoils (panansonic) can individually be turned on and off. Thy are just dumb radiuators at the end of the day all your controlling is a fan. Commissioning the Zehnder unit the weekend which has the intake cooling/heating battery also in the ASHP loop so will see how that assists as well.

Have you tried setting the flow temperature via the adjuster that normally is accessed under the handle on quite a few mixers. Allows you set the base mixing volumes. You would need to dig the manual for your specific mixer.

I had a similar problem and bought a new rubber seal kit from Screwfix, possibly this one. It was not a very good fit and was prone to spring out again. Eventually I put a block of wood behind the connection to keep it all pushed in place. Maybe the other kind would be better. The pipe was however long enough to reach past the "ridge", I think you need to fit it like this as it will help centralise the pipe in the hole whatever seal you use. IIRC the hole in the ceramic was centrally on the axis so I didn't have your problem. You could cut radial slots or holes in the end so even if pushed right home there will be room for the water to escape from it sideways.

That should be a godsend. You can run on it and build on it. Break it up later unless your levels are wrong. I've never understood the desire to throw away z slab then put it down again.

Hello. I am an MVHR Designer and I thought I would weigh in on some of the posts made, as I think they are a bit misleading. This is incorrect. Where i-joists are used, rigid ducting is the norm. The major advantage being the ease of cutting holes in i-joists, and the amount of holes that can be made (following guidelines on the data sheets). People often think of semi-rigid (flexi) ducting as space saving, but clearly with this type of joist you would require far more holes because there are far more ducts. A good designer will ensure the guidelines for holes are not breached. It is straightforward to cut duct with a hand-held grinder, even with a 1mm cutting blade. See my post above, rigid ducting is the norm where i-joists are used for the floor structure. 28m3/hr down a 75mm duct is fairly standard for a lot of companies, however, an optimal design will use two ducts for this flow rate (or higher). Bearing in mind that lower air velocity = lower pressure = lower sound. Most people would rather spend a bit more, have more ducting etc to have an inaudible system, over saving a few quid but having a system they can constantly hear. This is generally true. Rigid steel ducting tends to be lower pressure/sound. Semi-rigid does get unnecessarily harshly judged in my opinion. I have designed perfectly good systems for Passivhauses. In my experience it is due to many early systems being in semi-rigid, and were poorly designed and/or poorly installed. Even though it is straightforward to make connections airtight, I see more often semi-rigid systems with leaks due to improperly connected ducts to manifolds, plenums, etc. With rigid steel duct you just push it together once and it is airtight. And lastly the high volume of air many companies design for each duct. When I design I aim to put less than 26m3/hr down a 75mm (ID) duct, and less than 18m3/hr down a 63mm (ID) duct. To the OP, it looks like a nice system.

Yeah that's a lot of BS, we've had the same issues in Scotland with that felt. On slated roofs we don't have battens and it's still an issue. Just a cop out from them making a shitty product.

Before you go spending a lot of time and effort could I point out my recent experience with a mini-split. I had assumed that the cooling effect would be like the heating but just the opposite way round. Not so, when heating the effect is very localised but when cooling the cold air sinks down and spills across the floors. So one little mini-split is cooling the whole of our ground floor.

Interesting. I have just had EXACTLY the same problem. The membrane? Roofshield.

Yup. You should be making the runs as least resistance as possible, to ensure fan speed is minimal and audibility is low / non existent. Remember to include box attenuators at the machine to kill the noise at source. Install them on the ducts to atmosphere also if you have neighbours / other noise close by.

BPC gave me this general advice for 75mm ducts Do not place valves above showers (Outside shower area) · Place the Kitchen Extract Valve near the sink, not above the cooker. · Kitchen, Bathroom, En-Suite and Utility Valves require a double duct run. · If the duct run is greater than 15m, double the ducting. · If the duct run is greater than 20m, triple the ducting. · If the room is greater than 20m2, the valve requires a double duct run. · Do not exceed runs of 30m.

(Or should that be 'if only I knew then what I know now...'?) One topic that I am keen on is thinking in advance is how elements of the house will be maintained once the build is complete (we only just have planning permission so are early in the process). I am sure lots of people have lessons that we could learn from based on mistakes they have made as well as the thought process that they went through in drawing up their detailed plans. I get the impression that there are some well explored areas and one would hope that architects/technicians will have the experience and/or checklists to methodically work through so that maintenance is considered. However, as a self builder I am sure there are lots of traps we can walk into. Does anyone have any checklists or could they point me at this sort of info if it has been discussed before? As a starter for ten I am thinking about MVHR units and their filters (both within the unit and on the external ducts into the building). Lots of these units seem to be in the roof so the ducts are high up, yet surely the filters are going to need cleaning at least once per year. Where we live we get loads of tree seeds and pollen which will clog up external filters in no time at all. I am not looking forward to the prospects of climbing up tall ladders in increasing old age (or paying someone) just to clean a filter. We are thinking that it makes more sense to have these lower down (but then not too low due to a host of other potential issues this could lead to). What have the rest of you considered (or just got wrong )?

Yay! 🙂