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just to add another side to this argument as we've had 2 trades do this. our flat roofer gave us a quote which we accepted and he then fessed up that he mis-measured and wouldn't need as much seedum as he quoted for and charged me less. i would never have known and it shows his integrity (and which is why i have recommended him elsewhere!). and our tiler gave us a quote that we were happy with and accepted and then at the end of the job he said he hadn't used as much material as he initially thought he'd need and gave money off the quote. so, just to counter that there ARE good people out there. 🙂

“To err is human” (so don’t beat yourself up mate) the person that’s not made a mistake has not been born yet 👍

HI @Coanda You are quite right, however the same 263m3 air flow unit will do both: the same push of air in, as the push of air out at the same time...... otherwise the building would blow up like a ballon... 😂 So this would be one 263m3 unit....

As warm air rises, have you checked the air temperature up there? You may find a ceiling fan can shift enough to raise the temperature lower down. You could try it out with a desk fan first if you have one.

I have a Topdon TC001. It's between £230 & £280 on Amazon. I used it a lot for work. Very happy with it. Really small but you need to choose either the TC001 with usb c or TC002 for IOS. Some images:

It sounds very difficult. At least the floor area of the house would give you an estimate of the maximum multiplied by your 0.5m height. Here is a price suggesting ~£50 per cubic m for polybeads - which feels about right. May save for buying more, but will have fitting costs: https://ecclestons.com/product/10-cu-ft-expanded-polystyrene-bead-bags/ At £25 per sqm, that is the same material cost as a posh carpet, or decent tiles or laminate. The way full fill works is it can come in a tanker and is pumped in, usually after you have lined the space with polythene to keep moisture out (!) If you are not able to line, you need to pay a lot of attention to moisture and ground conditions. Also I think to keeping Roland out when he considers visiting; polybeads are probably toasty for rodents in winter. It has also been done with a material called LECA, which is Light Expanded Clay Aggregate - a clay version of an Aero Chocolate Bar, in granules. It is more resilient to moisture. Here are some "LECA insulation fill" prices in bags - looks pricey! https://www.specialistaggregates.com/advanced_search_result.php?search_in_description=1&keywords=Leca Insulation Fill Price&delivery=pallet That LECA is around £130 per sqm at 500mm thick, at which price you might be better off using Aerogel Spacetherm on top in a subfloor. I think you need to map your void - do you have access? If you can see it can you map it with a torch and an estate agent laser measure, a protractor and graph paper? Plan B: Can you do it on top as a raised insulated floor, instead? Plan C might be perimeter 'skirt' insulation in a trench round the house, and letting the ground heat up underneath. I do not know how an underfloor void affects that. Either way, it will need some careful staff work first. HTH Ferdinand

Hi @Tosh I think that the red crosses are showing that the volume of air required at the indicated room outlet would have to travel too fast down the size of pipe suggested. This refers to the extract ducts.

Hi @Tosh It would really help if you showed us the layout. Usually you require 1 inlet any non wet room and one outlet on any wet room (wet rooms are loos showers kitchens, bathrooms, shower rooms and any room with a supply of water including utility rooms). However with larger or longer rooms you may need an inlet and outlet. I see nothing exceptional after looking at the design

Thanks for the help. This is the stage ive got to with it now

You might be being a bit premature. The CoP of the Gen 6 isn't great at low temperatures, and if you are having defrosts they can knock 6-8% off the output. My overall CoP when the outside temp was freezing or below has been 2.4 to 2.6, but the SCoP so far is 3.77

+1 - have a look at full fill with eps beads. Otherwise I fear there will be a lot of swearing and cursing and a poorly finished insulation layer. I also believe that once it's filled with eps it no longer needs to be ventilated as it ceased to be a ventilated void.

Try it without steel. The Romans did.

Two things to consider when buying an MVHR unit, based on sizing. Normally the bigger the better, they make less noise for a given flow rate than a small unit only just big enough. The other is allowing for turndown, once you have it commissioned and build signed off, as you may want to reduce flows especially if a few people live in the house. So all things considered a unit that has your duty point in the middle of the units capacity range, us about right. Your lounge also needs a good flow rate as it normally has plenty of people in it.

Octopus worked for us ..... pronto-ish.

Every MVHR company I talked to could not / did not want to see the point that I made to each of them - very politely. There is a conflict of interest inherant in the way systems are designed and marketed. The supplier designs the system. The only way round the issue is to ask another (2?) companies to quote for the same job. Compare and contrast, post here and we'll confuse you some more 😑

My concern would be what residual space you'd leave yourself to crawl - and indeed *work* in. If you currently have no insulation (you don't say - how old is the house?) you'd probably want at least 150mm of PIR. That will leave you 300mm for you to crawl in. Mainly it will be wriggling as you won't be able to bend your limbs much. Are you very very not claustrophobic? I have done loads of tight underfloor insulation jobs, but few where I end up with as little as 300mm. Nevertheless I now get claustrophobic in small spaces. Think seriously before you proceed! Getting half-way through and realising you cannot complete the job is very frustrating!

That misses the point I never really realised, if said zone is behind a mixer it doesn't count. Yes they can, mine has volt free contacts that allow two settable flow temperatures for heating and two for cooling. You can only do one temperature at a time. So could us a diverter valve with microswitch to control it and simple time switch. Not sure about that, mine inhibits defrost when doing DHW. You just compensate with slightly higher flow rate to compensate. So mean flow temp is ok.

OK, to try to avoid this one running and running... Was the extension signed off by Building Control? The 2010 Regs (in force 6 years ago) stipulated a flat roof U value of 0.18W/m2K. If it was done right and checked it will have a U value of 0.18 - probably 125mm PIR, or 150 if, like me, the builder was a bit of a pessimist. You *could* go further (and Passive House builders will be looking for 0.12 or even lower, but 0.18 is fairly respectable. If you risk possible moisture issues by going further why not stay where you are? Like I said, if you can find a datum inside and out you could measure.

It sounds OK in theory. The beams are normally deeper than the blocks, so you need to stop air flowing between the insulation sheets and the blocks. Is there concrete blinding to work off?

We blocked the inside terminals for the Air test. Took the White Covers off - Stuffed car sponges in [in plastic bag] and then sealed with 150mm Silver Foil Tape, cut into nice semicircle. In hind sight the sponges were not needed, but it was fun going into B&M and buying 24 sponges Remember to switch it off.

Just in case anyone look at this in the future for a 'case closed'! The GRP guy gave up immediately and has invoiced for the correct quoted figure. So thanks for all the advice to back me up! Much appreciated to all.

DHW settings: if tank is big enough run only once per day and ideally on offpeak electricity set DHW run time and anti-cycling time so as not to interfere unduly with heating target temp as low as you can tolerate, 43C sounds fine flow temp limit max 10deg higher (so 53C) hysteresis 10deg or more turn off legionella cycle if you are regularly using most of a tankful every day Heating: Open all TRVs fully (if any) to start with, then use only as backstop for any rooms that overheat Run HP 24/7 Increase setpoint by 1 or 1.5 deg during any periods of cheap electricity Setback 3deg (at most) at night and (if on Octopus Cosy) during evening peak electricity period. Use WC, check curve is not still on default setting (or worse, set up for a boiler), try 0.8 and reduce (or increase) no quicker than 0.1 every 24hours. Disable load compensation/room temp sensing to begin with Set max flow temp, min flow temp and OAT HP off threshold to sensible numbers.

Commissioning is very straight forward, the main thing is getting the air out the system before you start. Then set a low flow temp and press start. Initial run should have all thermostats set high, see you are getting warm water everywhere. Once running they look after themselves with out much or any input. After 24hrs take a note on we here room temps settle to and start to balance the system. And see what DHW does make sure the 3 way valve opens, you will need the G3 person to sign off the cylinder commissioning. As for temperature outside almost any temp is ok, but with the freeze valve you are best to get the system filled and running above zero. (Still not convinced by freeze valves)

Basically check you have immersion heaters kicking in. Set a low flow rate and leave it to run. If you are heating a floor, it will take as much heat as you throw at it. Wind any room thermostats out the way see where is settles. Something like 28 deg flow. Then check to see if you are getting lots of start stopping, certainly for the first 24 hrs while it heat soaks you be getting very steady running.

It really annoys me that heat pumps are singled out whilst noisy oil or gas boilers are unconstrained, except possibly by a complaint to Environmental Health. What is really needed is a unified standard.

Get yourself something like this and HomeAssistant - and anything else you want to run - will run faster than on a Pi. https://www.ebay.co.uk/itm/386317625023 I installed Proxmox first, then HomeAssistant inside that. It's been great. Edit: £69 is about right to pay. Prices are higher pre-Christmas on many listings Edit 2: This is the one I have for £10 less https://www.ebay.co.uk/itm/176078465130

I read the whole report a couple of days before I saw the Telegraph article. My instant reaction to the Telegraph headline was that it took a warped (or determined) mind to come up with the headline given the actual content of the report.

One advantage of Zigbee2mqtt is that your ZigBee network doesn't restart (and temporarily go offline) when you restart home assistant. I've got home assistant running on a raspberry pi 4 and I'm very impressed. The UI is very easy to use, I've got some quite advanced stuff running without having to resort to custom YAML config yet. I also found a great backup add-on that syncs backups into Google drive for disaster recovery.

It's hard to call it an equivalent as frigate is far more limited functionality, but for me that's a real plus as frigate does everything I need in an easy to manage package, with massively less grunty CPU and power consumption. Get an edgetpu for it though if you possibly can. Keep blueiris about for doing device discovery on new cameras, it's the best I found for that. Articles rave that frigate must be run "bare metal" but IME inside docker is just fine. I do have the edge tpu though.

They don't know everything. The fee doesn't allow much time for research. It is easier / less risky to ask you to do more than less. I suggesf you just say that you've decided to tape and joint instead.

You can run Homeseer under Linux. Mine runs on a Raspberry Pi 4. It also has an instance of Home Assistant running on it, an old version. With that version you had to delve into yaml for anything but the simplest stuff so I haven't played with it much. It may have improved since then. One thing that I did find was that it could talk to DeConz at the same time as HomeSeer, so if you're using DeConz it should see all your Zigbee devices and you can control them from both HomeSeer and Home Assistant. I've moved to ZigBee2MQTT and MCSMQTT so Home Assistant no longer sees Zigbee devices.

That's doable. I went with zigbee2mqtt instead of nodered but I'm not doing any automation.

If the floor is well tiled and sealed it'll be fine. I would be slow to put any wood on the cold side of the insulation as water vapour might condensate on it and rot. You'll need to if you opt for Wunda however unless you want to use a cement board instead or a thin screed beforehand. If it's lightly to be in an area regularly wetted like near a kitchen sink or a bathroom then you could tank the OSB before tiling. I would consider a floor level drain like a wetroom in the case of a flood caused by a burst pipe etc. I wish we had done it in all the rooms with water in our house. Imagine coming back from holidays and finding a burst pipe has harmlessly drained for a week into a drain. Mop the puddle, fix the pipe and you're done. If it happens in our house it'd flood the entire house until it reaches the level to get into the shower tray downstairs ☹️

Hi @jaybird - we are in the Borders and not knowing how far down the road you are to securing a plot etc,. I wish you all the very best. Take a look at my blog if you have time to waste. It is a record of how we got from being in your position, to where we are now. You may find some bits useful?

Well, @Jaybird, I wish I'd discovered this particular Commentriat before we'd started building 8 years ago. So, you've started out right! Well done. Good luck, and try to forgive @Pocster as often as possible. All artists should be much forgiven. He's doing his best, but my God, imagine being married to him! Ian

Another point. Last December's cold snap was damp and dull and lasted two weeks. That was a particularly bad combo as we lost a lot of solar gain during the day and the high humidity meant even more defrost cycles for the heatpump. All in all, I estimate that 2 weeks of struggling cost us an additional £150 in electric. At no point were we cold, tho. This spell is forecast to be a bit less cold, bit more importantly sunny during the day with temps initially 5-7c. So much less of a challenge . And yes I know a lot of people here know their heatpumps better than their partners, but some of us just plugged the things on and got on with life 🤣

Roofs completed, gables built on one house and half way up the other. The roofers start on Monday after a delay in deliveries due to me changing the roof tiles. I had both the LABC and the warranty inspector out on Tuesday and they have passed the houses off with flying colours. 😀 The LABC inspector was there for about 7 minutes and the warranty inspector for about 2 hours. I now know all about the LABC guys divorce 😂 Onwards and downwards now. I can't wait to see the back of the scaffolding and regain access to the rear of the site for the landscaping before I say goodbye to the forklift. My next battle recommences with the DNO. It is now 19 months since i first applied for electric connection quotes and I feel that I am no nearer getting connected now than I was 19 months ago. Oh and I just had another council tax bill for a building that was demolished in July.

It sounds a mammoth task Back in the day you could pushed a small child under there and pay him thrupence But the PC brigade have put a stop to that now Or maybe a small Polish builder If you manage to pull it off Take plenty of photos As this is something that will keep coming up on here Best of luck

Did a major (expletive deleted) up . Missed the fact a cupboard door couldn’t open as hitting a corner plinth . Solution ? - move all the wall units back 18mm - (expletive deleted) that ! Company can have a custom corner plinth made that’s 18mm narrower …. Phew !

He said he wouldn't even necessarily do a site visit either! What exactly is the point of them??? Very important role. Reading on BH we hear of bad experiences with incompetent builders. There would be far more problems without bcos. These could become big issues to later users of a property. Then there are the incompetent self builders....they aren't on B H of course.

He said he wouldn't even necessarily do a site visit either! What exactly is the point of them??? If he does it woukd be when it's totally completed, ....everything important will be hidden by then! He'll just see me exquisite taste in decor......is there a code for that 😉

I'm shocked the Telegraph would twist the facts to suit it's agenda Shocked!

Thanks @PNAmble Will check that out. I also wanted to avoid phone attachment as I'm not convinced it'll be compatible with the inlaws Nokia3310. 😁