Bitpipe

Agree with @ProDave - we became accidental landlords back in 2011 when we bought the house that was eventually demolished to make way for the new build. Sale market was v slow back then (which worked in our favour for the purchase) and the finances were not that complicated to arrange. We let the original property easy enough as it was a fairly 4 bed new build, but it was still a big PITA and it looks like it has got worse by an order of magnitude since then. in 2011 we were able to offset the mge payments against the rent to minimise the tax impact (gone as an option now) but still had a bill to pay when we eventually offloaded it on the captial gain as it's no longer your main residence. Also, very difficult to sell a house with tenants in it as it never looks its best. Ours only shifted when it was unoccupied, neutrally redecorated (especially kids rooms), every room dressed with simple furniture (lots of freecycle couches and bed frames, inflatable camping mattresses under empty duvet covers etc,, ) big non functioning flat TV in living room, dining room set for dinner etc - all the show home BS but it worked!

There isn't one, as far as I recall, the external box that has the stairs just sits next to the other structure with EPS insulation in the 200mm gap between them. Not seen any movement between them in the 7 years since construction.

The sum total of our passive basement design was thus - design a basement structure, specify EPS grade that it sits on (EPS200 for us) and EPS to the sides (EPS 70) and ensure that this external vertical insulation layer meets the insulation layer from the above ground dwelling. Airtightness is easy, just need to lap the internal membrane from above down onto the basement wall below and tape. Spec PH grade windows & doors for basement and you are done. Ours has no heating and it always a comfortable 20 degrees. If I was doing it again, I'd have openable windows for more rapid cooling in as it can get quite warm when a few people in there.

I think it needs to be habitable and have an EPC before you would get a standard high st mge on it but all dependent on the surveyor. Have to say the last few surveys we've had for re-mortgaging were very simplistic and seemed to mostly consist of measuring dimensions of rooms.

I give them a clean once or twice a year. I Give them a good suds wash first with fairy liquid to loosen the dirt & rinse with the hose and a carwash brush attachment.

We have a 120m2 basement which contains 4 rooms plus plant (kids dens, gym etc). BC wanted sprinkler or external egress, so we went with latter. +1 on getting a SE to spec the ground investigation works. Depending on the site history it's normally a bunch of probes to 10m or refusal around the footprint of the excavation to determine bearing strength, 1-2 6m boreholes for determining soil composition and perhaps some gas/water monitoring left behind in the boreholes for 6 weeks. You only want to do GI once, we had to repeat due to sloppy work by the original on site supervising engineer and had to pay for some of it as the GI firm argued it was all part of the unknown nature of GI. We were in an urban environment, demolishing an existing dwelling and records showed an old filled in gravel pit within 100m of site - as old records are not reliable, concern was part of our site could have been made ground - turned out (after 2nd survey) that all was good and a slab foundation would suffice. Contamination studies would be required if planning conditions mandate, however your muck away contractor may want reassurance that the spoil is inert for the cheapest disposal. If the site is truly greenfield then you may be ok without any of this - any previous use or any made ground in the vicinity (like old workings etc) would trigger this condition. We specced a pit with external steps - water was not a concern in our build as it was below 6m so we made the main basement structure waterproof concrete (sika warranty) with below slab and external EPS insulation, the pit was a separately cast open box which butted up to the insulated main structure. It has an aco between the stairs and external door and the pit slab has a sluice drain to a soakaway - has never given us any trouble.

Yup - I was able to share with my own SE and the timber frame firm and it made life a lot easier. I'm sure they could have replicated from the planning PDFs but was useful noodling around with them myself.

Problem is, processing card payments is not simple or free for a merchant. There are two parties in a card transaction - the issuing bank (bank who issues the customer's credit/debit card - may not be the bank you retail bank with) and the receiving bank who act on behalf of the merchant's payment service provider - i.e. where cleared card transactions go. In between are the 'schemes' Visa/Mastercard/Amex that set standards and manage interoperability between all the various parties. This costs the merchant money - usually somewhere around a 2.5% per tx fee plus other fixed costs. Also, money does not automatically flow to the merchant - it's typically held in an escrow account for a duration until cleared. Disputes are arbitrated by the issuing bank, scheme and receiving bank and can result in a chargeback for the merchant. Schemes can impose higher tx fee on merchants that have a high chargeback rate. I suspect cashflow & chargeback are the main reason contractors / suppliers will not accept credit cards for payment (vs fees which they could charge onto customer) and will want BACS transfer as they get the money immediately and with no risk of clawback.

This is it - risk reduction vs elimination. Some of it is doing best possible research, some is ensuring the lowest risk payment method & terms. You will still get problems. We've probably had 3 major issues on our build. 1) render company used what was a BBA approved carrier board at the time of installation but turned out to have issues and has been quietly withdrawn by the major supplier. Impossible to pursue any action against the supplier and render company since gone out of business but were making best efforts to resolve. Latent defects insurance proved useless, refused to cover replacement cost which would be very substantial at today's prices (especially once the removal of existing and VAT added on). More of an aesthetic issue vs compromise of the rain screen (for now). 2) Glass balustrade company did all work contracted but final piece of glass incorrect. Went into receivership just after we noticed but as we'd been paying for work via credit card, got a resolution from our bank. 3) Groundworker firm clearly cut a few corners when reinstating basement (using spoil vs clean stone) when I was not around to supervise. Not obvious at time but the area to rear of house continues to settle and patio paving now a bit wonky, despite landscapers best efforts to create a stable surface. I with held the final 2.5% of bill due to other, more minor, quality issues at the time and the problem is manageable to resolve. You can't eliminate risk but you can soften the blow or, at a minimum, tell yourself that you did all you could to prevent - this is often the most difficult part of the experience to deal with.

We had one as a condition when we did our basement, trigger was some neolithic find some 20-30 years previously when a new estate was built about 150m away. There was not much choice of agency but the one we used had a reasonable fee for a scheme of investigation (to initially satisfy the planning condition) and a one day watching brief while our GW dug a few trenches. Nothing of interest found, they wrote a simple report and job was done. All for a fixed fee, just over £1k back in 2016. The costs do escalate if anything of interest is found.

Also, make sure it's clear from the outset who owns the design and ask upfront for the DWG files to be part of the deliverable at each stage. Having these made our life so much easier as we were able to pass them to the TF and basement SE and also used them ourselves (using a free cad package) to take measurements, check site dimensions etc.

We used a good local architect to design and take through planning (which took a few goes). There were some issues, like traffic management etc, that were not part of the house design per see but needed satisfied and the practice had expertise on hand to address. They also knew how to navigate around the planners and deal with the games played which we would have been too inexperienced to do. Once we had an approved plan we took control and acted as the PMs - discharging conditions, getting quotes, managing suppliers etc. We stayed on good terms with the architect but felt that his services post planning were expensive and more associated with traditional build methods and a single contractor approach (detailed designs, tenders etc). We commissioned our own SE to design the basement & ground elements and used a turnkey TF supplier who did included detailed design and SE for their elements. We used a private building control firm to handle that side of things. Really depends on where your skills and comfort levels are at. Some builders here never used architects at all and some use them right into completion.

Our geology is Thames Valley gravel / chalk which often has solution features (aka holes) so the slab had to be thick for that reason, we also wanted an open box design so the walls cantilever off the slab.

Our 110m2 basement (300mm thick slab and 200m thick, 3m high walls) containing over 16t of rebar PLUS the 300 m2 timber frame house on top with render & slate roof is all sitting on 300mm thick EPS 200 grade - a 2.4mx1.2m block of which was 35kg and you'd struggle to leave an impression on it with a finger. I guess this (or an equivalent grade) is what you're seeing in the image above. The SE figured the point loading of the whole construction and we selected the EPS grade that just exceeded the spec. By comparison, the sides of our basement were insulated with EPS70 - much softer (and cheaper) but enough to resist any sideways compression from the ground.

There's a few cm between the blind and glass but they are very effective at minimising the solar gain - only have had them up one summer so will see how they perform this year. 10mm gap between the blind material (we have 3 in a row) but this does not seem to be an issue.