Bitpipe

I'll send you a PM with my engineer - based in Bath but do work all over. Can also ping you the details of the Uxbridge based firm I used to build it.

This is what I did. The SE are ultimately the customer of the soil survey as they'll use it for loading calcs, slab design (i.e. whether piles are needed). They wrote the spec and tendered it out. We had a mix of 10m probes and 6m cores plus gas and water monitoring for 3 months after, plus contamination testing (for LA condition and muck away classification). We had to have a second survey due to some errors in the first and general uncertainty about the ground conditions (suspected made ground based on historical maps). It's still way cheaper than starting to dig a hole and then seeing what you find and if it's going to be too expensive to build it, you can drop the idea. Our basement is one of the best parts of the house tbh, Just over 100m2 split into two pairs of interconnecting rooms - kids use one half for TV, music etc and the other half is a gym and craft room/reading room etc. Lovely bright space, always at 20oc. Cost was £1000/m2 before fit out but we had a very accessible detached site and had demolished the original so nothing in the way.

We used these guys, did it all remotely and decent price. http://www.eco-survey.com/

And if it were a firm price, it would have a 15-20% contingency added on before hand to cover his @r$e.

Our tiler did the wetroom prep which included the backer boards, membrane, electric UFH and latex on the top for a few hundred per room (we had 3) - I supplied the kit & painted the walls with the liquid membrane after he'd put the edging strip on. Plumber had done the Impey tray first fix. Was DIYable but he just wanted to get it done and not hang about - also knew what he was doing which was a plus

And if you find one they're either lying to you and will hit you with a massive 'extras' bill at the end or they're desperate and risk going bust before completion. Or they may have won the lottery and are just building to keep themselves busy...

Will certainly be more expensive - you're paying for the efficiency. Cashflow and budget are not the same thing. Budget is money you are prepared to spend, cashflow is what you have when. If the whole build pot is sitting in the bank then cashflow is no issue. There is also a well worn philosophy of the quality / cost / time triangle. You can have two at the expense of the third. So a high quality lower cost build will take a long time (debatable if the cost is that low tbh as time adds its own cost). a quick and low cost build will sacrifice quality (or completeness) keeping in mind that BR & planning impose a minimum 'quality' a quality and quick build (or low effort from your pov) will increase cost.

They were more less the same price as the LA BC, who I'm sure are just as competent but I have heard are overworked and some can be a bit officious and slow to move with the times. There's a bit more of a customer service ethic with the private ones but they won't let anything slide though. Our guy actually saved me a load of hassle - I was all set to put a SVP through the flat roof at the back of the house where our bathroom is, but one thing and another delayed the work. Was not looking forward to it as it was going to be a pain to make airtight, waterproof and would have generally looked crap. Anyway, the delay gave me the opportunity to discuss an alternative idea I got on this forum (from @JSHarris I think) about having the SVP distant from the house. As we were in a caravan at the rear which was plumbed into the main sewage run, I asked BC if I could put it there and hide it with a planter or something. He surprised me my saying that as the houses either side had a SVP, I didn't need to bother as the SVP was for the benefit of the sewerage system, not my house and the new rule of thumb in a dense development was one SVP per 10 dwellings! So used AAV instead at the head of the stack and avoided all that hassle - thank goodness for the plumber forgetting his hole saw that day

Each of our blinds came with a 4 core 13A cable (two lives to drive the motor in each direction). These needed a bit of care to make sure they came through the airtightness properly, and then wired into a fused switch location. Same story for the Velux. Can't imagine how tricky that would be with a cable for each pane!

Our (private) BC guy first popped round when we were doing some site prep & drainage to kick it all off. Next visit was when the basement steel was erected and he quickly saw that it was a quality job so didn't stay long. After that we saw him after the frame was erected but before any first fix, he had a few comments for extra things that we sent photos to prove had been done. Came back just before the cavity was closed (plastering) and then did a pre-final inspection and a final inspection. Each visit was very efficient (20-30 mins) and most of our interaction was by email with photos for proof of actions raised plus the required documentation, plans, calcs etc. This was on a 400m2 house over 4 floors inc. basement and detached garage

From a VAT / cashflow point of view, the initial phase of your build will be exempt from VAT aside from professional services (like SE, surveys, architect etc), plant hire and kitchen appliances etc. full list on the HMRC website. Anyone who contracts for you, whether labour only or supply & fit need to zero rate their services upfront (they usually just need to see your planning permission), so that helps with cash flow. Anything you buy directly will have VAT applied but you get a one shot reclaim when the build is deemed complete by building control or when occupied for a substantial time (some debate on this at present) so that is not so good for cash flow during the build but you do get it back later. Anything you build/buy after this point will attract full VAT so will be 20% more expensive, so hoarding materials that won't deteriorate over time is a good strategy. Also, if you use any kind of single contractor / project manager to manage the build etc then they will want paid for their time on top of any building work. If it's a general builder this is factored into the cost of the build as an overhead, a PM is a professional service. Managing the build yourself removes this cost, however you then need to price your own time and see if it's a genuine saving. Again, taking on the work of actual trades (where you don't need certification to work safely & legally) is a question of time vs money. You may get the same eventual result doing it yourself but it will take much longer and you will have a degree of trial and error which will mean your material wastage will be higher. You'll also need to invest in tools if you don't have access to the right kit. You may need to take some classes if you're going to tackle more skilled work like plastering etc.. However, if you have spare time in the day then you can commit this and I'm guessing if you're building on the family farm then you don't need to worry about working past 6pm or at weekends from a disturbance point of view. Have you read The Home Builder's Bible? A good starting point as Mark lays out the step by step costings for a fairly simple house and explains what the variables are that can save or cost money (e.g. slopey site, high spec finish etc..).

I enjoy teasing the cat with it...

I'd expect there would be a man poking about on a ladder for 20 mins, plug a whatsit into your socket and then, with much shaking of head and sucking of teeth, tell you that the inverter's had it, system needs re-calibrating and the panels could do with a nanotech polish, and he'll do you a bargain price of £2000 to put it all right.

A service? Like an oil change? Worst that happens is they get a bit dusty until next time it rains. However I can see that a large number of PV owners are not as savvy as this community and could well be bilked for some meaningless activity.

I have the Venetian style overlapping shutters - when fully down they're quite dark but not 100% blackout. We have them on the street facing east side of the house for privacy and to minimise morning solar gain. Kids rooms are on that side and I take great enjoyment each morning opening them up to wake them

That's because they're not really 'built in'. They're appliances finished with a door to match the kitchen. The general VAT principal is that claimable items need to be part of the fabric of the house and not easily removable.

Looking back at my quotes, was a bit more that - £2k for ducts & fittings and same for unit, but this was 2015 so prices will have shifted - although I see the unit on sale for £1700 ex vat from BPC (https://www.bpcventilation.com/vent-axia-kinetic-highflow-r-h) again, that unit would likely be oversized for your house.

Commission involved turning it on. That was about it. About 18 months later I got round to balancing it just to get the BR sign off - took a few hours of running around. Can't say I noticed any difference. Maintenance involves looking at the filters every month or so and if they're dirty - giving them a good hoover. Replace them every 6 months or more frequently depending on how soiled they're getting. I bulk bought a load off ebay and they work fine. Once year, I lug the heat exchanger out and wash it in the bath with the shower. Leave to dry, quick blast with the hairdryer and back in it goes.

I have a large house (basement, two floors and room in roof) and use a Vent Axia Sentinel Kinetic plus unit from BPC - it was about £1500 and the associated ducts etc about the same again. I installed it myself (and I am fairly incompetent). Runs at about 30% for normal use and 50% at boost. You should be able to get away with something smaller and need less ducting etc. It's a standard MVHR with summer bypass - no heat pump or enthalpy unit so just delivers heat recovered fresh air, no heating or cooling capability/ BPC did a system design for free from the TF plans and there was enough leeway in the supplied materials and design to make it work once the frame was erected. I probably should have specced a few steel penetrations, would have made life easier but managed to squeeze it all in. Balanced it myself too, borrowing the measurement tool from the forum for £10! And yes, in summer I have plenty of windows open and just let it run in the background to extract bathrooms and ventilate the basement.

Our bins are collected on a Friday. We live at the end of a cul-de-sac. Friday was of course the day our timber frame, windows and insulation were delivered

I'd say about 200-250mm rockwool (couldn't see exactly, could be more) on inside face and the brick slips panel had a 30-50mm layer of EPS as part of the system. Roof obscured so couldn't see what's in that.

I'm a governor at the local senior school (both kids go there) and got a site tour today of a new 3 storey teaching block that will be completed in October. They're at the 1st fix stage so structurally complete. Really interesting to see the construction method... Steel frame with poured concrete floors, the external walls are framed with what looks like galvanised ribs to which a heavy cement board is attached with ring nails. The exterior has an insulated brick slip facade that has an inner metal reinforcement. Internally, rock-wool is layered in between the ribs before the cavity is closed with plasterboard. The internal walls are very robust, twin layers of 15mm PB either side of a 40mm insulated galvanised rib (to minimise sound transmission between classrooms). Underfloor heating and air-con - didn't ask about airtightness but didn't see any membranes. Also, boys and girls loos are now a thing of the past, all unisex units each with a lockable door and own sink & hand dryer - also used by pupils and staff alike.

Really enjoyed this series - the Irish architect was always more 'out there' in design, so got chosen less often, but his triangular extortion in the first episode was very clever, especially playing with the floor levels to demarcate living zones. Agree that it's refreshing to see them stick to the budget in a practical fashion (no painted OSB as a wall finish here). We agreed that a VR representation of our build would have been cool, not sure we'd have changed anything but it was only when the frame was fully erected with internal walls etc that we were confident that our design decisions were correct.

"You always find something in the last place you look for it".

Our spark had a spreadsheet of costs that covered first & second fix combined - broken out in terms of spotlights, downlights, switches (single, double etc..) sockets (single, double) data points etc, etc. Then single items for one offs such as heating controls, distribution etc. All based on standard materials (e.g. MK) and then adds a premium if you want to upgrade to chrome, satin etc...