Alex C

A thought on your cladding. I looked extensively into using charred timer. The black charring will wash off over time and the timber will silver. This may be good or bad but don't think your house will stay looking a nice solid black colour. As an example look at the grand designs house of the year beside the loch. It is no longer black at all as all the charring clearly got washed off by the rain.

I have a passive spec house and agree with all the points made above by others that do as well. Your architect may be qualified to design a passive house but if he dosn't actually live in one he may not fully appreciate things like the risk of overheating from sun and fires. There is no way you will ever use a log burner. Your south facing double height glazing will massively overheat the room. The brise soleil as drawn will do nothing except for a couple of weeks around the longest day when the sun is really high in the sky. A normal rule of thumb with brise soleil is to make them protrude from the build by half the height of the glass they are shading. Even this would have overheating issues in spring and autumn. You have quite a good roof overhang on the south side to shade bedroom windows in mid summer, this will be helped more if you recess the windows well back into the wall. Even so the bedrooms are likely to overheat without any external shading. External venetian blinds as used by others on this forum and also myself are not an expensive luxury but a necesity in a passive house with lots of glazing. I would also worry about your lounge cooking in the evening late summer sun Bed three and four will have a real issue as there is no cross ventilation in these rooms to purge at night . I assume windows on master and guest open on north and south elevation to provide cross ventilation? My experience is that night purging with a large roof light works really well in an open plan house, but useless if it isnt open plan or you shot your doors. I would also suggest getting rid of the sun tunnels. You have. passive spec house, then are making 14" holes in it with an uninsulated tube. Budget for some quality light fittings instead. I would suggest that for such a grand house the corridor on ground floor is way too narrow. I think it is also a massive mistake to make your dinner party guests leave the grand dining hall and squeeze past your muddy boots to take a pee. Generally I think it looks a really interesting build and I'm sure will be a lovely place to live.

Not sure on the spec of your build but my council planners agreed to remove this when I told them I was building a passive spec house. They were happy to be shown I would be using far less energy to heat the house than a normal building reg standard new build.

I have a passive spec house with a tiled ground floor slab. I would say definately have ufh having lived in the house through the winter. It is not that you couldn't heat the house with another heat source, but that it is not comfortable walking round the house without shoes on with a cold unheated slab. I found that with the slab at 20 degrees or cooler the floor felt quite cold to the touch, whereas if it is only a couple of degrees warmer it is fine to walk on bare foot. I found it only took having a heat input once or twice a week over the winter for a few hours to keep the slab topped up to a comfortable level. Our slab is slightly thicker than most at 200mm and with ufh about 100mm down. This was due to the amount of steel but seems to even out temperature fluctuations really well. If you heat the air rather than slab you may also find it dries it out and may well be unpleasant to live with. With the cold dry snap of the beast from the east our relative humidity in the house dropped to 35% and normally runs at about 45%. We put electric ufh in bathrooms and used it all winter for an hour a day, the tiles felt cold to the touch without it. Also have wet heated towel rads in bathrooms which I ran for an hour a day over winter to boost the upstairs temp. We have no other heating upstairs but this worked really well.

Interesting read about air changes and humidity levels in Passive houses

With my MVHR the house meets building regs if you turn the control to 3 out of 3. We are a family of 4 in quite a high volume house and have found we can run it at 1 which is I think lower than passive house level. We never even use boost as there is only ever steam in bathrooms if the kids have long showers one after the other and this quickly disappears. House is approx 700m3 and I set the extract at 100m3 per hour. The figures given to building control were with fan set at 3. They didn't question it at all. I have a number of humidity sensors and these show a pretty constant 45% and dropped down to 35% over the cold dry weather we had recently.This would suggest there is no problem with humidity build up even with low extraction rates. It never ceases to amaze me how quickly washing dries in the house. There is no point whatsoever in having a tumble drier.

This comes up quite often. A polished concrete slab that is poured and polished by a groundworker with no roof over the top is going to be rough at best and terrible if it rains or is cold/hot when poured. If you want a beautiful polished concrete floor you need a specialist contractor and it needs to be covered. As mentioned above the best results are actually a polished screed rather than structural slab.

A very snug 22+ here as well. The only heating input for the last 9 days has been the sun and 3 towel rads for 30 mins a day. Loving that South facing solar gain.

My building control officer has asked "If you have underfloor heating, this should have a commissioning form completed to show that it has been balanced, tested and commissioned properly." The layout was drawn up by MBC and laid in my slab. I connected it to a manifold and the plumber did the rest, so he didn't actually design the system or give me any flow values. I have an 8 port manifold but just run everything as one zone so super simple. Is there an official certificate that Building control are going to want or could it be just a note from my plumber to say he installed it properly? I have measured the floor temp all over the slab and there is one loop that is running a degree hotter than the rest and one running a degree colder. Do I just increase the flow in the cold zone and restrict it in the hot one? All ports on the manifold are currently running at 1.5 to 2 l/s with the pump running at half speed.

I also had an MBC passive slab with thickening under line and point loads. The Structural engineer that MBC use is paid for by them and I am pretty sure MBC would be very interested in the engineer designing the cheapest solution for them to build. EPS is often used in civil engineering projects as land fill under structures rather than pouring masses of concrete. I assume this is for cost.

The ones actually building their own houses don't have time to take a day swanning round a selfbuild show. The time to go to a show is before you start.

MBC laid my pipe and did the layouts. Just make sure about spacing. I was told by the guy in the office that they always lay at 100mm spacing, but the guys on site said they always lay 200 centers. The pipe was good quality stuff off the roll. I fitted my own manifold and pressure tested prior to concrete and also kept an eye on pressure level during the pour.

@dogman if you complete your build of a 300sqm mbc house for 300k I will come and buy you a pint. I assume when you say doing everything yourself, you mean absolutely everything.

I haven't look at your costs in detail, but what most self builders don't take in to account is that a QS is normally going to cost a job to what you would pay a main contractor including there overheads and profit, and will nearly always err on the side of caution with figures. Typically in the southeast a one off build to a high spec is likely to be in the region of £2000 a m2 main contractor route but more like £1500 m2 if you are running it yourself and doing quite a lot of work. My build has come in bang on budget at just over £1400m2 for a pretty high end fitout passive build, but then I have been on the tools full time for a year and worked really hard to keep control of the costs. There is no question that ours would have been a £600k build through a normal main contractor route. Also in my experience architects are terrible at costing a job. Most of them just do not have enough time on site to really understand what stuff costs, and also keep track of rising material and labour costs, which in the last year have been fairly significant for materials at least. To be honest a budget of £250k to build a finished house sounds optimistic at best. You can't use the same m2 figure on a small house as a large one as you always benefit from an economy of scale.

Its all pretty meaningless as if you have any pv there will be enough power to cover the background use for mvhr during the day anyway. I modelled my own house for SAP and has been mentioned before it is not designed for really efficient houses. The score for a very average house is not really that far away to the score you get from a passivhaus, although the real running costs are likely to be very different. The pretty average new builds down the road from me scored a B, mine is passive spec and scored 101 A. Any buyer is likely to think they are almost the same efficiency

Being able to slam a door in an airtight house is just down to how big the gap is under your door. My bedroom doors have about 7-8mm and you can slam them but my downstairs wc which is a massive 2.4 high door only has about 3mm from door to tiles and you cant slam that bugger however hard you try. I need to get round to taking a couple more mm off the bottom to help with air circulation. I should have make the kids bedroom doors a tighter fit so they couldnt slam them.

My experience with ecology is very similar to above. I achieved 89 without solar pv on a passive spec build and then managed 101 with 5.5kw of pv. I was aiming for 100 for a discounted rate. I knew all along though that the discounted rate would only be for a few months as it is a 2 year mortgage period and I started the clock running on that one before I even knocked my old house down.

Good to hear you got on ok with it. There is a steep learning curve, then it gets really quick to paint. Some of the youtube videos show running the paint through a screen to get lumps out but I found just using paint from a new tub and stirring well worked fine. As you mentioned you don't want to paint out of an old half used tin that has flakes of paint dropping off the rim.

Reading this with interest as it is also my next job. You use cross section at sensor end, this is why most ones you can buy have 100mm dia head and then taper out to make the maths easy.

I bought and used a wagner project pro 119 to paint my house. A great piece of kit to use in an empty house. I will sell mine if you are interested and any where near surrey to pick it up. I think it was about £600 including a better gun and another £40 for a spray tip extension to paint high ceilings. I wouldn't bother with anything smaller as the paint would need thinning too much to get through the nozzle.

My German tiler was super fussy about everything and worked to a tolerance of about 0.5 mm, but even he tiled straight to the mbc slab after putting down a primer (not pva). If you can get hold of a laser level go over the whole floor with a stick with a mark on it and see for yourself exactly how out of level it is. Mine was within 5mm except for where it dipped by 2 doors, and that was easy to bring back to level with more adhesive. we have a large open plan ground floor with over 100m2 of 1000 x 500 mm tiles, didn't use decoupling matt and didn't have expansion joints, just a good quality flexible adhesive. Finished result is absolutely perfect with zero deviation between tiles. With large tiles you need to make sure they are a good quality and flat as some have a bow in them, and make sure they are fully bonded not just on dabs of glue. In my part of the world good tilers cost £40 per m2 for labour only. As a side note, if you have very large open plan areas on a floor of that size, your 600x600 tiles will look quite busy.

Thanks for all the speedy responses. @jack Maybe i have been over concerned about using the loxone for control. All it will be doing is acting as a temp sensor and glorified timer. I always worry slightly though when you need to open an app or laptop to access basic things, like altering heating settings. I guess the reality is once it is set up to how we want it will never be changed again. I can't ever imagine wanting to turn on my heating when i'm on holiday or any other such home automation nonsense.

I am at the stage of fitting the controls for heating of my passive and slab and as others have done I want to be able to circulate the water in it without heat input. Any suggestions as the best way to do this, My electrician has suggested using the loxone automation system and relays as it is already installed, but I would rather it was done using standard controls so anyone can fix it if there is a problem. Heating is via gas boiler. @JSHarris I was planning originally to run 2 zones off the 8 port manfold with 2 room stats. My plumber although good is very old school and has not been much help with suggesting ways to control this.

If you cut firings for falls and fit the osb 3 I have a local contact for doing the fibreglass who did a very tidy job at my place. Easiest way to cut firings is with a track saw. Interested in your balcony glass detail as well as I still need to get round to ordering that.

My tiler is just finishing off laying 120msq of 1000 x 500 tiles on my passive slab where he had to use adhesive to make up for undulations in the floor up to about 5mm. The result is absolutely perfect. There was one day where he had some help in, the result of which was less than perfect, but I just made him take the whole lot up and do it again, and told his help not to bother coming back. My tiler has told me that in over 20 years of laying floors there has only been two occasions where he has not had to make up levels at all, as even what appears to be a level floor can vary by a couple of mm which with a large tile will be noticable. It is a real shame that your pm left it so long to put a stop to this as it should have been obvious on day 1 that your tiler was rubbish.