Thorfun

our MVHR outlets are 250mm reducing down to 200mm pipework internally. just fyi. but we have a larger house with 90mm semi-rigid ducting so I guess we need to bring in more air.

welcome. I hate to put a downer on this exciting time for you but, and I speak from personal experience, don't spend too much on ideas/designs/architects/site investigations etc until you've exchanged contracts! we spent many thousands on a previous property only to be gazzumped about 1 week before exchange of contracts. money down the drain. best of luck with it all!

when you say 'pro' version are you talking about the 'Industrial' or the 'Trade' versions?

mine was designed by TSD (Tanners Structural Design) and had 90o insulation. in fact, where you have the raised area of hardcore/sand we just used more insulation. here's ours for reference. that above is using the Kore preformed insulation but our groundworkers just bought EPS300/EPS100 without the sloping former and cut it to fit on-site. photo below: hope this helps and it's posted with the caveat that any changes to your foundation/slab design should be ratified by your structural engineer.

still quite large though albeit kind of midway between the 1.67mm and 4mm - 5mm others have. I can guarantee you that I will end up not bothering! it's one of a 1000 things on my list of things to do and think about and it is rather rapidly moving down that list.

If ridge height is a limiting factor can you consider a contemporary building with a flat/shallow mono-pitch roof? Mira not to everyone’s taste but with a good architect/designer on-board it could be a wow factor and also does away with the limited headroom upstairs. just a thought

How are you and who is insulating the roof? If you’re doing it I highly recommend cut rafters! Having almost finished installing 190mm mineral wool between the rafters and cutting PIR to go underneath the rafters I can honestly say I wish I had a cut roof! but, if I was to do it again I’d go for really wide cut rafters ( or I-joists) and find someone to fill with blown cellulose.

yeah. this is a good idea. our groundworkers wouldn't start until things started drying up a bit in April, although they were digging 3.5m down to build a basement!

the trials and tribulations of trailblazers. hope you get it all sorted.

welcome. looks amazing and I look forward to reading about your journey on here if you post. not sure about finding a good tradesperson to start in 2 months. it's my experience the the good ones are booked up for a while. also, one of the first things I learnt as we started our on-going self-build journey is that things ALWAYS take longer than you think. so, even though you think you'll be ready in 2 months for the TF the chances are you won't be. lead time for the insulated slab, groundworker availability, material availability, trades taking summer holidays/sick days/popping off to do other jobs etc all makes things take longer. Also it is a lot more stressful trying to stick to a tight timeline (I speak from experience). once I figured that out and started leaving a couple of weeks at least between stages, i.e. foundations and TF, TF and windows etc, the stress levels reduced substantially. good luck though and I wish you all the best on your journey.

I'm using professionals for the stuff that can be seen and doing the stuff that's hidden myself. that way no one will ever see my bodges. 😉

our carpenter was originally going to face fix with them but then when he saw the T&G profile he changed to fixing through the tongue. so, you can use the tongue-tites either way!

reading through your quotes makes me thankful I decided to not use a main contractor for our build! at £3k/m2 our house would cost us £1.35m. I'm hoping to get it in for half of that. granted I am doing a lot of the work myself so it's taking quite a long time but I'm thoroughly enjoying the experience and learning new skills. project managing the build takes up a lot of time but I enjoy talking to the trades that I have on-site and learning from them by asking questions. I've found that if you show an interest in someones work they're more than happy to talk about how they do things. obviously, you're not a very hands on person @puntloos and so that is why you will end up having to pay the main contractor to do the work. it's just the way of things. you can do it a lot cheaper but it will require a lot more work on your behalf. I understand the 'hand it over and get someone else to do it' mentality, it just didn't work for what we wanted to achieve with our budget. I wish you the best of luck on your project and look forward to seeing the progress.

I presume that the architect is also paying for the SE as well? I can't see how it's right to tell someone to do some work without getting authorisation from you who will be paying for it! 🤦‍♂️ anyway, it's done now. hopefully your SE will be able to give you the details to build the garage at a later stage whilst keeping the insulated slab. best of luck.

through the tongue for us. chippie says not an issue as the T&G holds it all together and stops the boards curving round. ours are still being fitted so no pictures oh how they age.

Interesting. Will add them to my search list in the future

is B&Q really cheaper than ordering online?

we have Cordex under the insulation laid on a bed of sand laid on hardcore. here are our SE drawings for that detail. and here it is in-situ 🙂. you can see the three stages in one photo! the far bit has hardcore, the next has the layer of sand blinding and then the cortex in the bit by the basement wall. we used TSD for our foundations who are excellent with insulated slabs. you definitely don't have to do it the old school way. obviously all depending on the correct SE calculations!

here's a photo of our 'arms' on insulated slabs which sit on 2m deep trench fill foundations. here are the trench fill foundations for the 'arm' closest to the camera in the photo above. and with the insulation and rebar on top ready to pour the slab. hope this helps! 🙂

this is the important step! definitely run it by the SE. we have 'arms' attached to our main house that has a basement underneath and those arms are also insulated slabs but are sitting on strip foundations. so there's no reason why you can't have the garage on an insulated slab and 'attached' to the main house later if you want to. obviously if it's ok with the SE! 😉 some might say that there's no need to insulate the ground of the garage but for the cost of the insulation I'd do it as you never know if you want to convert it at a later date to a habitable room or not. will be easier if it's insulated now.

Is this not a question for your structural engineer?

got our tongue-tites from https://tradefixdirect.com/stainless-steel-screws/tongue-tite-plus-stainless-steel-flooring-screws-35-x-45mm. bulk buying works out at about 4p per screw

read through the thread now. very impressive indeed! but I don't have the space in the plant room for anything like that. might have room for one of those pre-made inline filters that were linked in the thread though. I'll speak to the MVHR designer and installers and see what they suggest with regards to insect mesh, pre-filters. but maybe, I am, as usual, just worrying about nothing and shall just clean out the MVHR filters more regularly.

thanks. didn't find that thread in my search! will read with interest.

sounds complicated. might be easier just to clean the filter in the unit more often! I presume also that as I'd have to clean the mesh behind the grill regularly that the grills can't be glued in any way and will need to be attached with screws? I guess I could vacuum the mesh through the grill slats if I did use adhesive/silicone to affix the grill and seal around it?