Bitpipe

We have one ground floor south facing window in the kitchen that does not have an integrated external shutter - all the east facing windows (street side) do, plus all velux windows. Makes a huge difference in solar gain. Given the south window faces next door's gable end, I thought it would be fine but got caught out by spring and winter sun when it is low in the sky. Been kicking myself on that since the build started.. Now the render is likely to need replaced, I'm going to take the opportunity to order a shutter for and get it retrofitted in the frame ahead of that work. We also get a lot of evening sun through the west facing sliders (two four metre doors), but a cheap voile from Ikea on a tensioned wire hanger (£10) seems to solve most of the issues as the solar gain is less intense at that time of day.

Both of our (never used) balconies open out onto decking upon flat roofs. If you have inward opening doors then you could get away with a Juliet style balcony. I recall this incident from the US on the dangers of poorly constructed balconies - this one was not correctly constructed and the timbers succumbed to dry rot. Was big news back home as the majority of the dead were young Irish working on J1 visas. Balcony was not overloaded per the design. https://en.wikipedia.org/wiki/Berkeley_balcony_collapse

No, I like the render finish and if the battens are correctly fixed to the underlying studs (which were marked) then there should have been no issue - an unfortunate oversight that will cost them a few £ but they're very professional and have never shirked from their responsibility.

Another year on and we're getting closer to resolution. I put a temp probe in the render cavity a few months ago and have been logging every minute so clearly saw that the temp inside fluctuates with the external temp, no build up. Render company boss came out today along with Brendan from MBC (who co-incidentally was working on a build not 10 mins away from us) and looks like root cause is that the render battens hit and miss the wall studs behind the external weatherboard, so as the boards expand, they're pulling out the fixings on some battens. Next step is to chop out the render on a small side wall and see for sure. Then the only remedy is to strip it back to the blue paper and start again! Obviously they're less than delighted but have committed to do the right thing and the fact that they're back on site 3 1/2 years after doing the work is encouraging. So, if you're rendering a timber frame house, make sure the render battens are aligned with the structural studs....

I bought electric UFH mats from eBay at a fraction of the cost of UFHSS range - I also binned the cheap stats and bought nicer ones. Mats were Warmstar I think... had a full warranty as long as you followed the request to use a multimeter to check resistance while in packaging, unrolled and installed and notify them if it deviated from the specified figure. Also bough the little 3 wire (L N E) alarm box that goes off if there is damage while laying. Once it'a down and has been laytexd over it's harder (but not impossible) to damage. Obv once tiles are on it is bomb proof.

Also take into consideration paving like we didn't and end up with an IC half on and half off the main path to the house We had to trim it and use a concrete paver as a lid for the part that's in the garden, then turfed over it - still serviceable but was a PITA!

Lots of practical advice here - http://www.pavingexpert.com/drainage.htm I watched our guys do it - didn't seem complicated they used a disc cutter to cut pipe & chamfer the edges and soapy water to slide the pipes in. Biggest challenge will be getting the inverts & falls correct plus the effort to dig trench, lay shingle and backfill.

To be fair, we're not using the rooms in roof regularly (extra guest bedrooms) and the basement is about half occupied (still full of post moving in junk) so the per m2 is probably not as low as it looks.

Agree, plus general comfort level (especially in summer). For a close on 400m2 house, we're averaging about £1/day gas and 83p/day electricity once the FIT is taken into account.

Don't think it was me - we had a thick mature beech hedge, about 9ft high, at the edge of the front boundary which made it impossible to see into the road when leaving the house - we had permission to remove it and replace with a planter wall set back a few m from the road which looks much better and is safer. What I do remember is a neighbour, who is a conveyancing solicitor and was the major objector to our PP (7 page legalese letter, all dismissed by planning), tried to suggest that the hedge be subject to a TPO to preserve it, but the council said that hedges are plants not trees so can't be protected.

We scraped an A with PV and passive standard insulation, airtightness etc.. I recall that confirming the UFH temp was part of the nudge that got us over the hump but it was close.

Yup!

I have done this. Believe Nick gave me the method. Two ways: 1) Screen on tile (wet room) , used 8mm alu U channel and bonded base to tiles with Sikaflex and then more Sikaflex in the channel to take the glass. No fixings on the horizontal run (but some on the vertical) 2) Screen on shower tray (non wet room) no alu channel on the bottom - balanced glass on 2mm spacers and sikaflexed along the 2mm gap between tray and glass. When it had gone off, poked out spacers and filled gaps with sikaflex

Normally goes to a 3rd party lab. A quick google found this - https://www.ecofficiency.co.uk/waste-soil-sample-testing-kit They have a mail order kit for £55 (courier collected) and the tests cost from £125 for basic WAC classification to £225 for more detailed analysis. I'm sure there are others. WAC testing is used to classify spoil for disposal/landfill, we did it for our basement and it was considered inert which is the cheapest outcome.

I submitted in November, 18 months after moving in (but 2 months after getting BCO sign-off). Required external & landscaping work (i.e. condition of planning / BCO) continued up to the claim date. Was 100% honest on the form with dates etc. All got paid in full, no quibbles. However, there are reports of it going the other way so it may be dependent on which individual processes your refund and what they had for breakfast etc.

Technically, a warranty is required for any mortgage related activity, even re-mortgaging. In practice, they may not ask. Or, like my surveyor, (when I was moving from an Ecology self build to standard residential lender) ask and accept 'yes' as an answer but not ask for any evidence. The warranties themselves are practically useless - I only got one for the lending implications.

I considered ICF for my basement, then thought about ICF for the rest of the house with a SIPs roof on top - however that was coming out quite expensive. Also looked at an all ICF system, including roof & floors (Thermohouse) but still too much. Settled on a cast in situ 'open' basement that mimicked the perimeter of the MBC passive slab design with a suspended steel / timber floor and MBC passive house on top. Had I gone for a capped basement then it would have been just like one of their raft foundations to build off. I got MBC to design their part first and handed it over to a SE to design the basement underneath, taking all of the point loads into consideration. When the basement was built, I had MBC take final site measurements before putting the frame into production - meant a few weeks of delay but peace of mind. All worked fine.

GI are usually fairly risk adverse and will identify any potential issues, however remote. We are 100m from a historical gravel pit, since infilled in the late 1800s and now with a 1990's 'exec' housing estate on top but it still nearly derailed my project as some anomalous test results were interpreted as potentially made ground requiring piling etc. (never mind the associated archaeological condition as neolithic fragments were found in said site when the estate was built). We had to re-do the testing, all results were clear and when we actually excavated the basement it was pure clay, gravel and chalk as expected. Turns out original overseeing engineer had cocked up and was subsequently let go but I still had to pay twice. If the site is a former garden then you're probably fine - the substation would need to be leaking some to contaminate your site. BTW, for contamination testing, you normally only send in one sample, representative of the area you are disturbing - ie footprint of house. £1000 sounds excessive - I'm sure you can get it much, much cheaper if you take the sample yourself - may not satisfy the LA but will reassure you if all clear or give you negotiation leverage if not Can you get access to site and surreptitiously take a few small samples? You don't need to go very deep - just get below the top organic layer.

Get in the photo habit - you always assume you'll remember where something has been buried, put behind PB etc but you never can... I have hundreds and wish I had more!

Remember that VAT registration is based on declared annual turnover (70k ish?) so anyone who is under that threshold is probably not that busy, especially at London rates. If you have someone who will open / close the site and take deliveries etc then you've solved one of the main logistical issues of working without a main contractor. You really don't need to be that involved while the work is being done, your job is tee up the next set of work and make sure all the materials are there at a price that works for you.

A few thoughts... As this is a renovation / extension of a dwelling that you're occupying (vs a demolish to ground & re-build or refurb of previously unoccupied building) then you have no scope to reduce VAT, aside from using trades that are not VAT registered, which in London I think is unlikely. So, you hire a turnkey contractor who will be 'one throat to choke' and if you agree a fixed price there should be low risk in this approach, however as you have seen - these people have overheads to meet, margin to generate and you are paying for it. They will also not expend significant effort to save you money and any savings they do make go in their pocket, not yours. Next option is to be the PM and sub work out to smaller trades who will have less overhead. You increase the risk but now you pocket the savings. If you're buying the materials, you can scour and scrounge for the best price. You need to visit the site at least a few times a week, more if you're on the hook to open / lock up. With some juggling you can still do the day job and dedicate your evenings to planning ahead, ordering materials and reviewing progress. You will need to take the odd call during the day. Last option is to ditch the day job and pitch in - unless you've got valuable practical skills to offer, you're better off working. We did #2 and delivered the project under budget. It helped that we lived on site (caravan, family of 4 - painful but saved £££) and I could mostly work from home - even then, I mostly left the trades to it. Agree that unless they are PMing the job, ditch the architect (or agree a scheme where you can get clarification on demand). It's best to use a single contractor for the structural elements, avoids gaps in who is responsible for what. Once that's done you can contract your own roofing, windows, electrics, plumbing, plastering and joinery plus other finishing trades. Some will have preferred suppliers that they like to use (especially plumbers & sparks) others will be less fussed as long as materials are on site on time. It's not easy but it's not impossible either. BTW, you are already self building, it's a very slidey scale

When I was scoping out Gaulhofer windows, their UK rep took us to see a private build in Milngavie, north of Glasgow, which would have been thereabouts. Our 10mx11m footprint would have easily fitted in their kitchen plus they had a basement, and two floors above. Front door was almost 3m high and the sliders were over 8m each. I think there were only 3 of them living there too...

One other thought - like most building, there is a fixed and variable cost with basements that makes smaller ones quite expensive per M2 and larger ones much less so. While we had a variable cost on muck away, concrete, steel, insulation & backfill that was proportional to the footprint & wall perimeter, the crew spent quite a bit of time building the two key pieces of vertical form work (one a corner section with window, the other a flat wall piece) and were then able to cast two sections at a time and rotate around the slab in a very efficient manner. Only took a few weeks in total. They had a rule that one section needed to have at least 3 or so days of curing before they'd cast a fresh section against it - I think this was so the waterbar could be adhered to relatively dry concrete. So there was that fixed time plus plant mobilisation etc which will be pretty much the same whatever the size of basement.

I met the UK directors of Glatthar when planning my basement, they did one for a friend and did a very high quality job (at a high quality price). As my site & ground conditions were pretty straightforward (my friends were essentially building in the Thames riverbank), I was able to do it cheaper by building in-situ. They were scathing about him. While some of his advice is useful (general design principals etc) and he de-mystifies a lot of the building process, I'd be wary of using a one man band and a secret ad-mix etc. We used a very competent concrete team who did all the steel, shuttering and pouring and were able to spot mistakes in the engineers drawings which were quickly corrected. They used a warrantied Sika system (admix, water bar & expanding plugs for the shuttering holes) which was all supervised and signed off by a Sika rep, who then issued the warranty. The groundworker essentially dug the hole and filled it back in, following the SE's spec.

I did not put any heating in the basement but did build the 300mm slab off 300mm of EPS200 (50mm sand blinding, 150mm compacted type 1). Basement walls are insulated outside with 200mm EPS70, clad in 3mm corex to protect when backfilling. End result is that the basement is 20oc year round - no heating needed, solar gain from the lightwells, ambient heat from TVs, a fridge, and the plant room all seem to give it the heat it needs. MVHR supply to all rooms also.