Nickfromwales

The rubber makes a huge difference. I now use Killmat on any waste pipes over ground floor bedrooms / snugs etc as it works so well with the high frequency stuff, like water splashing etc.

Resilient bars are defo the wrong product, so I think you’re on the right path with your thinking. There are sound block rubber matting type solutions available, and I’d install that at the 6mm thickness, or 10mm if you can manage that, eg instead of the ply.

Off grid requires prediction / human intervention, that will never be out of the picture. Controls are only complex when you don’t understand them. Yes, ASHP direct to heating at first, and when the slab is up to temp ( satisfied ) the ASHP can run over into the TS / buffer for absorbing every drop of sunlight via that energy multiplier. Diesel genny would obviously not lose its cooling fan, just a 3-port motorised valve to toggle between that or the TS. Heat from the genny is incidental, not routine, and it’s waste heat if not captured. Can be further diverted into a solar coil in the UVC ( if it ever runs in the summer ), as ever, each instance is unique.

Absolutely. Apologies for the lack of info, has been a very long and arduous day…… EPS is cheaper than shoplifting so no excuses for not achieving as you suggest, eg 300mm all round aka passive raft / similar ethos.

You just wouldn’t go for a TS with an ASHP for both heating and DHW as the CoP would be out the window trying to get the stored temp up high enough to producer DHW. ASHP option needs to be at lowest possible temps for maximum CoP, so the PV in winter ( sub 25% of the same kWp in the summer ) remains effective. For every 1kWp of PV you should be aiming to produce at least 3kWh of heat energy, ergo a 4kWp array should be worth 12kWh of heat energy ( so installing a minimum of 12kWp of PV should get you, albeit conservatively, through a winter ) I would look to the slab as my thermal store, and incorporate a huge amount of thermal energy buffering at very low temperature. DHW should be via an UVC without a shadow of a doubt. Heating and DHW need to be segregated in an off-grid design IMHO. Generator for winter deficit should be a water-cooled unit, with that waste heat fed into a second set of UFH coils, or, if room for it, fed into a buffer cylinder that is shared between the ASHP and the generator. The buffer should really be a huge cylinder ( 1000L+ ) for bridging grey days where there is little ‘spare’ solar revenue. I aim to be ‘off-grid’ by next simmer, but grid tied for reliability / fail-safe.

Could I ask how you are eligible for this, as a new build?

If it’s just you, the plot, and a machine…… get stuck in Just keep doing a head-count of wife and kids. There would be very little excuse needed for me to hire a BFO machine and get cracking, and it’s got to be therapeutic too. Crack on, it’s not as iffy as it looks, just find out where the services are and go slow there.

+1 You‘d fit a thermostatic bypass aka Laddomat arrangement which lets the heat source recirculate back over until the device is up to a set temp. Only then does the heated water get sent to the store You may need a plumber who better understands this system, as that is quite basic knowledge in the world of wood-burning for heating. Eg; https://www.ebay.co.uk/itm/Laddomat-11-100-for-wood-boilers-up-to-80kw-Biomass-Wood-heating-Burning-/163652025906?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=710-127635-2958-0 Water will heat very quickly from the WBS, and that will likely not absorb all of the heat created by a burn, so beware of your thoughts there. If you’re going to fit an ASHP ( I’d defo not install a GSHP unless it’s a huge property ) then you’ll get an UVC anyways for DHW. Do away with the thoughts of getting DHW from the WBS then, as you sound like you’re not true “off-griddy” folk and want some life away from cutting, storing, drying and conveying wood to burn? If using wood for winter heating, you should budget about 1/2 a wheelbarrow a day, possibly 3/4, so would you be able to source and process that amount anyways? For DHW and heating you could just do away with LPG / oil auxiliary heating and just put all that money into PV and batteries to run the ASHP for heating snd hot water. Is the slab down with UFH pipes cast in? Is it a decent chunk where you can load shift heat energy into it?

Hi. Which manifold do you have? Not very good failure rate at all!! I have UFH manifolds that I fitted for clients which are coming up to their 20th year anniversary's and zero issue / failure / complaint.

If they are buttered before being laid onto 100% solid notched bed ( of adhesive ) then they will be as solid as lots of small 6mm thick tiles. 6mm is a thin tile, so think twice before going for that tbh. 6mm tiles on a solid bed of adhesive will be safe to lay, but if there are any voids under them, where the adhesive is not continuous, those areas will be where any cracks ( point impact damage ) will occur.

Just look at what happens when some cock buries a disposable BBQ on the beach

I would fit one immediately outside the galv housing, as I do with all external oil installs. As you state, there is no immediately apparent requirement for fire valves for an external boiler, but a bit of sense must prevail when the boiler is attached to the outside wall of a residential dwelling It's not meant to be pretty, it's there to stop a catastrophic fire.

This is what I do with every slab penetrations design, as it's just sooo much easier to not have smaller bore waste pipes traversing the walls / cutting units etc.

That sucks. Pull them into line early on, and remind them that you’re the customer. If you don’t gel with them, it’s time to get rid. For control, I’d go with something dead simple and robust, like Phillips Hue. You can put one of these…. https://www.philips-hue.com/en-gb/p/hue-tap-switch/8719514440999?origin=p70750597731&gclid=CjwKCAjwwo-WBhAMEiwAV4dybbII5hoxKPkNnTbYT7B8JOgZ_6bYAIChcNuD258EG2g72nzzeUJsshoCMJ4QAvD_BwE&gclsrc=aw.ds at the top and bottom of the stairs, or anywhere else, are fully wireless and can do scenes and dimming plus basic on / off. Plug n play, job done. As far as getting cables around, it’ll be a simple job of drilling holes and fishing cables here / there. A thin ‘ribbon’ type cable will be ample, but will all likely need soldering and gear-shrinking. A good electrician should do this in his sleep, but you may also do well to check with the staircase manufacturers to see where it’s best to do this. May save a lot of unnecessary labour / time if you snd the sparky have some help / insight

Yup. I bet there is little to no ‘glare’ off those. Nice lights btw. Less of a PITA to fit compared to the sink-in plaster lights, but they are worth the extra effort imho.

These have the lamps in the base and cast a nice soft spread up the ceiling. OCD on centres, height etc is essential so the ‘fans’ of light are all the same on the vaulted areas 👍.

I do most of the lighting designs for my clients, not rocket science really, just more knowing what products are best suited to which applications / locations. For vaulted, I quite like the plaster in up-lighters as above 👌. Pics don’t really do it justice tbh.

If the rads are off, +1 to it very likely being air still in the system being vented at the automatic air vent in the boiler. If the boiler does a pump overrun cycle after hot water has been satisfied, the pump will circulate the heating circuit water to cool the boiler heat exchanger down ( but this is manufacturer dependant ) and should be ruled out first. I would run the central heating flat out at full temp with all radiator valves set to max temp and do that for a full 1 hour. That will purge all the air from the heating circuit and only then can you really start the next processes of elimination. Yes it’ll be very warm, so time it gif an hour and go out for a while to allow the house to cool back down. Start there.

As a large electric shower is utterly cold mains dependant, it would be sporadic in performance to the point where it was unusable on any setting other than minimum. May as well buy a 7.5kW baby electric shower as it would be more reliable. Remember that this is an annex off a residence, and therefore, as I’ve not heard any differently, it is very likely to be fed from the main house cold mains supply. So, when anyone so much as fills a kettle, the dynamic pressure to the annex will drop to near zero by comparison, absolutely nowhere near good enough a scenario to suggest a very big 10.5kW electric shower as it would be 100% reliant on a “cold mains priority” setup which this likely will not have as residents could be in both the house and the annex simultaneously. Instantaneous DHW is a bad choice for this situation I’m afraid. A cold mains accumulator could be introduced, but it wouldn’t be my 1st choice, eg creating solutions for mitigating against the problems that poor survey / design / execution brought about. The only way high-powered instants would work at all reliably here would be if the annex were to benefit from its own cold mains water supply. Then there’s the electricity supply also, as a 10.5kW shower, plus water heater, plus space heating, plus sockets & lights = a minimum of a 60a supply to a chunky CU and a lot of extra expense / complexity. That’s if the existing 1ph domestic supply can handle the extra, new electrical loads….. 🤔

Why haven’t you just drilled straight out and lost an unnecessary additional bend? Then you make the external bend a T with a cleaning ( rodding ) eye on the end for self maintenance.

My comment was prompted by yours; AFAIK there is no mention here about the WBS providing DHW. It would be a hugely complex installation for an annex, and require a lot of components / plumbing / header tanks etc.

No mention of DHW via WBS?

12kWp of solar would give you a huge amount of excess, and if your DHW is instantaneous you would defo still be buying electricity even on a bright sunny day for all times where the irradiance isn’t at max / other base loads are not satisfied. With a cylinder and an immersion you could store all the excess PV generation as DHW ( plus other things ) and save a LOT of money each year as that setup would provide free DHW for prob north of 6 months of the year to both the home AND the annex. That 12kWp would diminish to sub 4kWp for the 3 months of winter, so will not even scratch the surface for space heating with resistive heaters. Used a heat pump ( which will run the split A/C, and that 4kWp will be equivalent to 12kWp again because of the CoP of the heat pump. Please ask for an explanation if you do not fully understand any of my blabbering The reason I ask about how far the annex is from the house is because it should be quite easy to tether the annex to a centralised plant in the house. My current clients want a WC and wash basin ( + DHW ) in the detached garage, so I have ducted between the house plant ( UVC location ) and the garage to run plumbing inside. I intend pulling 2x10mm pipes ( hot and hot return ) together, mummified with Armorflex neoprene insulation, to give the few sporadic handfuls of DHW p/a that the garage requires. A PIR sensor ( aka occupancy switch ) will trigger a pump which circulates DHW in a return loop to give instant DHW to the WC basin hot tap, and when the room is vacated the pipes will just cool and go cold again. The hot return will be required to stave off the “dead leg” that would be created if it was fed with just a single hot ‘leg’, but only really a requirement if the hot supply pipe run exceeds 25m ( risk of legionella ). Upsize that hot feed to a 15mm DHW supply and a 15mm hot return and feed it from the house and that’s your all of your DHW to that’s annex done for a few hundred quid of pipe and insulation. Space heating could be completely via A2A split A/C units afaic, and I would save the cost of the WBS install and use those funds to pay for the A2A system. A/C gives cooling in summer, essential for a gym(?), and space heating in the winter. The summer A/C will run from excess PV generation. The insulation levels are sub BRegs so are by no means admirable, and floating floors are cold-ventilated, so space heating in the winter wouldl benefit from the excess heat from the WBS if you do fit it as the floors will be quite a significant cold bridge during the worst of the winter, but it will likely give off too much heat for all other times, with that heat contained to the room that the WBS is in. MVHR will not distribute that heat btw. Another issue is, the chimney of the WBS will be a cold-inducing ventilation heat loss demon, which will be constantly reducing the room temps for all the times that it’s not lit. Going for a room sealed appliance would resolve this, but it sounds as though you already have a WBS? The MVHR is a bone of contention, because if you don’t get the air tightness detailed, AND tested, and get a score of <1 ACH ( air changes p/hour ) the MVHR will do next to zilch or less. Use this time and the advice available here to make some informed decisions

Heater or cylinder?

Buy and temporarily install the unvented hot water cylinder ( UVC ) that will end up in the house, and spend once. Electricity may be an issue with all this resistive heating, so what supply do you have? Fuse board aka consumer unit ( CU ) already in? You’ll need a 60a supply minimum, plus any resistive cooking will be on top. A single powerful instant water heater will be 12-16kW, and need an enormous amount of electricity. Over a year you’ll probably pay for the UVC, certainly when you add up buying and installing all this kit, plus you’ll be able to pee faster than the water comes out of an instant water heater, unless it’s 3-phase. Just buy the UVC and put it in a 2nd hand shed / temp outdoor structure. You should have a really long think about what will end up in this outbuilding and install the long-term kit now. If it’s to be a gym, you’ll likely be fit from A/C, so maybe fit some split units now for heating ( as these units will provide heating and cooling ) and, again, purchase once. PV will run cooling and divert to domestic hot water ( DHW ) IF it is a storage device and NOT instantaneous. How far from the house to this building?