Bitpipe

Ok, I'd look at the site insurance too as it was in effect when the leak happened and does not have the usual caveats wrt occupation that domestic insurance policies apply. HRMC do not consider carpets as building materials for zero rating but that does not mean they are exempt from your site insurance policy so you need to read the small print. Worst case it will cover the skirting and other remedial action. Would not mention the site insurance to the home insurance company at this stage until specifically asked - obviously don't consider making a claim on both as that's fraud.

It's a grey areas wrt domestic home insurance as to whether you're covered if the house is not officially complete when you take occupation. Do you have a completion certificate for the house from building control (local authority or private)? We took a punt and switched from site/build insurance to regular domestic when our property was broadly complete but still needed external works to get BCO sign off (which took 18 months). We also had a leak on occupation but fortunately got to it quickly and damage was minor - we were able to recover costs (£500) from the plastering company who put a screw through a pipe during tacking. Whose fault was the leak?

https://www.uvalue-calculator.co.uk/calculator/ https://www.changeplan.co.uk/u_value_calculator.php You add the R values for each material and then 1/R = the U value.

I struggled to find a plasterer and was doing a 4 floor build with 400m2 of floor space. Found one by being nosey and door stepping another local self build to see who they were using. Family firm who did the tacking, insulation (team of 3) and skimming (one guy). Took about 6 weeks in total from memory. Finish was decent, if not perfect, but price was good. My spark said I could have paid twice as much and not done any better (I did get quotes that were double what I paid). One of the tackers put a collated screw through the cold feed to cistern which only became apparent a few months later when we were commissioning the plumbing. They paid out for the remediation and damage (£500 or so) without any arguments which was decent. So that's my tip - go be nosey on recent local builds.

I got a £20 one from Screwfix, still going strong 5 years later!

if you use a rag soaked in IPA (not the beer) then you stand more of a chance. It really does stick like s#!t so scraping it off a painted surface will take the paint with it too!

I never used it to fill huge voids, it was primarily used to adhere big (1.2m x 2.4m) sheets of EPS to the basement concrete walls and then to fill any small gaps in between boards, that's where the gun is great as you can really control the flow and get it deep into the crevice. I did have a few bigger cavities to fill and just opened up the gun valve to let rip but given it's more expensive than the high expansion stuff, if that's the majority of what you're doing then maybe the single use cans of high expansion are better. Another tip is that if you're using it as 'glue' then making both surfaces damp helps adherence.

The 'one shot' cans of foam have their own plastic nozzle and are pretty much only good for that initial use (i.e. assume you'll use all the foam in one go) because as soon as it goes off in the nozzle you will struggle to use it again. Also it tends to over-expand - which is fine for big gap filling but not for more targeted applications. If you use the low expansion gun grade foam with a gun (Soudal is great), you can make a can last ages as the foam never goes off if you close the rear gun valve after each use. You may get a buildup of hard foam at the tip but can easily knock this off or remove with a knife. I've picked up a foam gun after 6 months and it's still been fine. I've never used the cleaner, just gone immediately from spent canister to new. Isopropyl alcohol (£10/l on eBay) is the best for cleaning the gun exterior after use and to remove wet foam from surfaces (but you have to be super quick). Always wear gloves and old clothes as it quickly stains your skin black and I've had to sandpaper it off in the past! I always had a square of cardboard or ply to sit the gun on flat as foam can weep out the top of the nozzle when the valve is open but the trigger relaxed. Once the gun did get properly clogged but I was able to strip it down and clear the blockage with a paperclip and length of wire, plus plenty of isopropyl alcohol.

It was passive standard so airtightness of 0.56 ACH, triple glazed passive certified glazing from Gaulhofer. Walls were 0.12, roof 0.1 and basement 0.1 also. https://www.mbctimberframe.co.uk/passive-house/passive-house-technical-detail/

The principal is straightforward - pre-formed high density (200 or 250 grade) EPS is used to form the slab perimeter and sheets used for the underside. Sits on a blinded, free draining stone base. Membrane over the top of the EPS. Reinforcement is then laid on chairs on the EPS base and UFH pipes are clipped directly to this. Services laid and then concrete poured (sometimes power floated) and you then have a slab with integral UFH that is fully insulated off the ground and to the sides. Savings on traditional shuttering for the slab and slab build up (e.g. xps & screed) offset the cost of the special EPS. The whole system needs to be designed for your ground conditions and structure above. The insulated layer of the slab is intended to line up with the insulated layer of the structure above so you end up with a complete insulated envelope around the structure. I did something similar when building my basement - laid 300MM EPS 200 to support the slab which was cast on top using traditional shuttering, as were the basement walls. I ensured the under-slab EPS extended at least 200mm beyond the concrete and stuck 200mm sheets of EPS 70 to the external walls using LE foam.

I suppose it depends on the cost of the planned roof covering - Jeremy used a recycled plastic slate, but I agree that 'cheaper than' is a stretch. However, if you use an in roof tray system then you can obviously subtract the cost of roof covering in the area where PV is installed from the overall PV budget.

If his 'mind palace' is sufficiently rich then he need never build it at all. Worst case he can just live out his days on VR like on Ready Player One

5 years in and our basement has never had any issues - any system will work provided it's properly specified and installed. But any waterproofing system that is not independently, insurance backed, warrantied should be avoided as if it fails, you'll be responsible. Given your ground water levels are so low, I'd forget type C. You will have pumps that will not be in use but will still require testing and eventual replacement plus monitoring systems for failure etc. Any water ingress risk is going to be from rainfall pooling at the foot of your slab so ensure you have a robust perimeter drainage solution - land drain to soak away at the appropriate depth - and specify backfill with clean stone. Go for A as your main barrier (get a decent warrantied system) and use basic WPC as your backup.

You're over thinking it. I don't think HMRC are that switched on. Anyway, any liability would sit with the contractor, not you.

I would not worry about it - if the contractor has agreed to zero rate then you're fine - technically the risk (not that there is any) sits with them. As their invoice has no VAT in it, you won't be including it in the reclaim to HMRC.

If you have something to sit between it and the ground then you should be fine. Axminster ?

Teram or equivalent geo textile is not that expensive and will prevent your stone from progressively becoming incorporated into the ground below it - rain as well as traffic will make that happen. It's a no brainer if you want to use the stone for something else later, as a sub base for a drive etc. A quick search shows 2m x 50m rolls for about £100 - what area are you covering?

A low U value, combined with good airtightness, is useful all year round. It will keep your interior at a consistent temperature in summer and winter. Being partially underground will also increase your temp stability as ground temp is pretty consistent year round. Decrement delay (how long your wall build up takes to transfer heat from outside to inside) is also key. I'd recommend a passive style slab - i.e. insulate the slab off the ground using 2-300mm high density EPS and if you extend that insulation just beyond your slab, your ICF exterior insulation should be able to line up and (assuming you design your roof appropriately ) give you a nice insulated & airtight envelope. We have a basement / timber frame house with this approach. You can then incorporate low temp UFH directly into the slab and if used with an ASHP it can cool the slab in summer. ICF inherently lends itself to good airtightness so you just need some attention to detailing to achieve a decent result all round. Solar gain is the usual reason for overheating so if you minimise this with adjustable blinds, overhangs etc then that will make a big difference - note that spring and autumn can be prone to overheating as the sun is lower in the sky. MVHR is there to provide adequate ventilation and minimise heat loss in doing so, it's not very effective at moving hot or cold air at the required volumes to make a major difference. If summer overheating remains a concern, make provision for a split air con (i.e. put the ducting in) and then put one in later if needed. No, as well as being time consuming and messy, it will have the opposite effect. As above, enabling 'stack' ventilation (fancy term for roof window + ground level ventilation) in summer will cool your house at night and then you keep it closed during day to keep the nice cool air in.

I'd guess a pressure treated timber soleplate - I have seen plastic equivalents for log cabin kits also.

Nope, the sparky just daisy chained the relevant neutrals together and it all works - I have a more detailed explanation somewhere but it's very low tech and very effective.

It's really not that complicated - some 15mm pipe at the end of the wider bore distribution and a pump plus either a stat or switch.

We have the return loop with motion / light switch activated pump (which also triggers MVHR boost extraction) and it works great. You may not always be using the loo in a bathroom and may just want to pop in to wash your hands.

Ark I think but they're now defunct. Plenty of others around. Nope, just waterproof concrete. There is a landdrain at the foot of the slab and the working cavity is backfilled with clean stone so a giant french drain. You'll need to get Sika to sign off on that but if the entire cavity is contiguous and is within the max single pour limits then you may be ok for vertical joins. Need for waterbar arises when you join two pours. At a minimun you'll need it where the vertical wall meets the slab (or stub kicker wall) i.e. the horizontal joins.

I did not use NHBC, that's for sure. I went through a broker, believe the insurer was called ARK however they went into admin but the policy was sold on and is still active. My ground investigation was carried out by a firm which uses chartered engineers and included bore holes, dynamic probing and gas/water monitoring.

I had to waterproof penetrations into my basement - the contractor cast in duct that each 110mm foul and the electricity and water supply came in through but for each there was a 5mm gap all round. I used Newton Stopaq 308 (https://www.newtonwaterproofing.co.uk/products-systems/products/concrete-joint-and-leak-sealing/pipe-sealant-through-service-duct-sleeves/) its a flexible compound that never sets (is quite messy to work with) - you pump it into the cavity once the cables are through and then seal the exterior with a special cement.