Russdl

How about a freestanding carport, half a meter or so away from the house so the MVHR isn't affected. Park the truck the other way round and have a slight fall front to back.

Don’t t discount that option, it brings many pluses. Not least being that the services will most likely be there. Getting services to a virgin plot can cost bucket loads. We were looking for a plot for decades and that’s finally what we found a bungalow that had reached it’s ‘best before, date. It wasn’t falling down but definitely had had its day and we got it for not much more than a virgin plot with planning permission would likely have cost. Good luck, it’s definitely worth the not inconsiderable effort.

@Bramco great idea. Mines still very much a work in progress but the more obscure stuff (Sunamp, Willis Heaters) is covered. And now looking at that photo I realise the house nickname on the spine text is upside down. Damn, back to the drawing board!

We have a fully electric house and could get close to blowing our 80 amp main fuse if everything was on at once, of course it’s not - not normally but on the current Octopus smart tariff I want everything on from 23:30 at night. We use a Willis heater for the underfloor heating (with the ability to use 2 if it’s really cold). If both of those came on at 23:30, plus the Sunamp and the house battery started charging plus the electric UFH and towel rails plus the dishwasher plus the washing machine plus the car started charging then the fuse would go. On the Octopus tariff I don’t have a huge amount of control over when the car starts charging so because of that I’ve restricted it’s charge rate to 4kW (I’m probably starting to use the wrong units now but hopefully you’ll understand). I know not to have everything come on at 23:30 but the next owner won’t (unless they read the Haynes style owner manual I’m writing). In the winter months I probably couldn’t charge a second EV over night, I should have gone 3 phase but I didn’t understand all of this before I made that decision.

How many EV’s are you likely to have on the drive in 10/20 years time? 3 or 4? You may want something faster than 7.5kW charger. I’d go 3 phase if it’s not prohibitively expensive.

Yes. Can’t wait to find out 😃

Doesn’t sound silly to me. Even if the condensate comes from every element inside the box you’d think it would all be herded together so it would all fall out of one pipe. Well I would anyway.

Is that 'standard'? I had no idea, seems a bit odd.

I don’t really know the answer but the Geocell replaces the Type 1 and the standard insulation. Clearly it’s more expensive than Type 1 but how it measures up against standard insulation I don’t know. We used it for a detached garage and it worked really well. If I were to build another house (ain’t/wont happen) I would definitely consider it for the insulted slab over the PIR bucket.

I’ve not looked at the condensate drain of an ASHP in any detail but can you not cobble something together out of guttering for example to catch the condensate and send it where you want it to go?

I got mine from here very pleased with it but it hasn’t had too much hard labour. Mainly spray painting, pumping up tyres and blowing dust around.

That looks neat enough, but it looks like it differs from your plan in two respects: 1. The window board is no wider than the window reveal. 2. The window board doesn’t protrude beyond the window reveal. I think those two points would be the difference between ‘contemporary chick’ and “why didn’t they finish that bit off?”

But what about the entrance to the garage? My slab is ‘thermally broken’ with a GRP box section and the easiest way that was going to work (in my head) was the foam glass route.

That looks like a lot of work for limited reward. I guess you’ll only see the shadow gap when you’re sat down? Also, when it’s finished will it not just look ‘unfinished’. I’ve never seen a shadow gap under a window board before (maybe because I wasn’t sat down?) Have you got example images?

It seemed to be the easiest way to achieve want I wanted achieve, no thermal bridge between the slab and the outside world. I had thought about that, that’s how the house was built, but I couldn’t work out how to do that without the thermal bridge?

The plan looks wrong to me, but I’m far from being an expert so hopefully someone will chip in with better guidance 👍🏻

It would be a long route but can you go up into the loft along the loft and then down on the other side of the beam? We did the same as @crispy_wafer and ran a lot of our pipes down behind a cupboard whose main job in life is to hide those pipes. How come you need to get 15 pipes through there? Are you double ducting each room? Seems a bit over the top if you are. Just looked again on a bigger screen and I see that indeed you are having two runs to most of the supply and extract valves. 4 runs in total to the dining room. Some of the valve positions look a bit odd as well. The kitchen for example, why is the valv not in the far corner of the room away from the outside door?

@gaz_moose Yes, we have a ceiling. The structural element for the door head is a ‘C’ section joist. The door head itself is formed with plywood and the sectional (not roller) garage door is attached to that.

No zinc roof. The pigeons are making a right mess of it, it’s black so probably nice and cosy for them but the rain doesn’t wash their output off very well.

@SimonD which side of Bath? I’m in Salisbury and can recommend one - no idea how far he’d travel.

Solving that thermal bridge was a big concern of mine in the very protracted thinking stages and once I had (well, I think I have, happy for contrary feedback) it drove everything else and I went a bit nuts on the rest of the plan. Hence the insulated slab, walls, roof and door. Hopefully it’ll stand the test of time - if we get a proper winter I’ll report back.

After going to the effort and expense of insulating the slab, walls, roof and door I had to do something about the transition from outside to inside the garage. Garage slabs normally extend beyond the door creating a big thermal bridge that I didn't want. What I decided to do was use some GRP box section to thermally break the inside from the outside. It's early days but it seems to work well and it hasn't fallen to pieces with cars driving over it yet, which is a bonus. I may be on to a winner. To start with I resin anchored some threaded bar into the slab and then bolted the GRP to the slab. I then rammed some left over foam glass into the gap underneath the box section for added support. I also used GRP angle as a 'stop' for the EWI on the returns to the door and the door head. I'd filled the box section with left over insulation and finished it off with expanding foam, added some left over mesh, shuttered it and made myself a concrete entry ramp. A quick lick of paint finished it off and it all largely seemed to go to plan as well. Here's hoping it stands the test of time.

A total of 19 'C' Section steel joists were used for the roof. We had two different sizes, the taller ones were for the larger span at the front of the garage and the smaller ones at the rear. The joist were mounted side to side and the 'fall' of the flat roof was to be front to back of the trapezoidal garage. To get the required fall I needed firring strips on top of each joist but with the fall being front to back and the firing going side to side each firring would be a different size. I couldn't get a saw mill to cut me 19 firings that were all completely different sizes so I did it with a skill saw. I also put a slight taper on top of each firring so that the roof boards would sit on the whole of the firring. That all seemed to work a treat and was less tedious than it sounds. The rest of the roof was standard warm roof build up: OSB - Vapour Barrier - 120mm PIR -OSB - EPDM. Getting 56m2 of EPDM up on the roof proved tricky. It arrived rolled up and I thought it might actually roll. Not a bit of it, it was reluctant to go anywhere. In the end we placed a couple of ladders against the roof and then used ratchet straps to hoist it up bit by bit. Once the EPDM was up on the roof the rest was a breeze, really easy to work with and stick down. For the external wall insulation, we started with a 300mm high band of XPS around the base, sat on top of the foam glass. Above that was Rockwool for the breathability and fire resistance. The XPS was finished in black render and the Rockwool in white render, we then filled the trench around the garage with gravel leaving 150mm of the rendered XPS as a plinth. I couldn't quite get my head around how the finished rendered rock wool would feel, it's quite amazing, solid as a, well, rock. You'd never guess it was rock wool under the render.

I wanted to build a garage/workshop that would be comfortable to work in year round and also keep the cars, bikes and tools that are stored in there in good condition so I decided I would insulate the slab and eventually settled on Geocell Foam Glass as it looked like it was going to be a pretty straightforward way of achieving an insulated foundation. We dug a hole and took the spoil to a local farmer on a Transit tipper, lined the hole with Geotextile Membrane and then bought the Foam Glass in. Access is a real problem for us so I had it delivered to a nearby builders merchant and then I trailered it in, two 2 ton bags at a time. We pushed the bags over into the hole and spread it about. Foam Glass doesn't really like being spread about, it has a coarse texture that grabs hold of everything, but it is very light and we got there in the end. Once filled to the required level I whacked it down. That was quite a difficult task as well as when I turned the whacker it would lift up the Foam Glass that I'd just whacked down. Again, I got there in the end though and covered the compacted Foam Glass with the membrane. It may actually have been easier to cover the Foam Glass with the membrane and then whacked it. Next time I'll try that (there won't be a next time!) I then built the formwork for the slab, lined it with DPM and set out the steel work following the very comprehensive plan provided by the SE. Concrete was poured and power floated as I was going for a painted floor finish (that changed...) The concrete was covered and left to cure following more comprehensive instructions provided by the SE and that worked well, not one crack has appeared in the circa 7m x 7m slab. The walls were going to be single skin blockwork so wind posts were required. I resin anchored those in place and then awaited the arrival of a highly recommended bricky. If the bricky had known how to use his laser level he would have been dynamite... Unbelievable really. I took the inaccuracies in the block work out with the wall plate so that I had a level starting point for the roof.

Thanks @Iceverge I’ll start another thread a bit later today regarding the Foamglass etc.