Bitpipe

On closer inspection that looks like a wood effect ceramic tile - which would be much more practical given it has a consistent thickness and should be usable outside.

I did similar with stone outside and resin inside. Getting the sliding door rail flush with the ffl required some careful thought and attention during design and build.

Not really, economies of scale mean that the cost decreases /m2 as the basement gets bigger - also gives you more negotiation leverage. It's a variable cost element for sure. Problem with having a basement in centre is that it provides no other function in supporting the house, you will still need a raft or traditional foundation. In our case, the basement replaced the need to have any other foundation so we saved £30-50k there. I'm in SE England so while not central London, not cheap. Rest of house was probably closer to 1750/m2 - averaged out at £1500/m2 (2015 prices). Basement specialists are almost always more expensive than regular builders - get quotes from groundworkers who will do the excavation and sub out the concrete works. No wet rooms as it's complicated getting waste water back up to ground level for disposal. Chunked into four rooms, two are kids TV rooms, one is (notionally a gym) and the other a book / craft room. Those last two still full of junk tbh. You should not have anything down there that won't go through a door or up stairs. a 300l UVC fits fine.

Basements can be quite expensive per M2 when small as there is a high fixed cost of mobilisation of plant. I accept that ours is large at 120m2 (external) but it does form the entire foundation of the house above. We experimented with 1/4 and 1/2 basement layouts but it was not that more expensive to go full size and the planners did not care. In the end it came in at less than £1000/m2. Is your basement planned to be habitable? Ours just looks like any other part of the house, apart from the plant room (2m x 3m) which is a bit more utilitarian inside. We have a full size oak staircase to ground floor etc. As we needed an additional egress point to meet fire regs, the plant room is next to the external door which is up a flight of concrete steps to outside. At the base of the door is an Aco to as soakaway, we used this to route the UVC overflow, Condensate from MVHR and gas boiler is pumped up to ground floor and mains drains. If we ever had a mega leak somehow then I guess we'd just pump it out the basement door.

Alternative view here - we looked into automation at an early stage of the build and given we are both electronic engineers working in s/w & h/w we were au-fait with the technology and more than capable of configuring it. Ultimately we decided against for reasons of cost and complexity. When we took a hard look at it, we couldn't find an automation use case that was so compelling that it justified the investment and commitment to cabling hub & spoke for lighting vs traditional ring. A few factors - Our house is quite large (basement, two floors and room in roof) so we would have needed a lot of kit. We have 3 standard fuse panels as it is and had to wire the house left and right to minimise cable density. We have electrical external venetian style blinds to east windows on toggle switches - i find we don't really adjust them much during the day. They never go up and down, at most we tweak the angle of the slats. We have Velux Integra windows in the hall and utility and have motorised external blinds on these and a few others - all are controlled by the proprietary Velux touch screen panels, again we don't really fiddle with them very much during the day. Heating is single zone on ground floor only and is rarely on as the house meets passive standards. MVHR is triggered by PIR and light switches in bathrooms, which also triggers the hot return pump We have a mix of ceiling LED spots, a few pendants & uplighters in the living/dining area and a 5a lamp circuit in each room and this satisfies all the lighting 'scenes' that we seem to require (eating dinner, watching tv, etc..). During the build we felt that we'd removed another source of complexity as our electrician had other builds where he was held up by the KNX firm delivering panels etc. One feature that I am envious of though is the ability to centrally turn off all lights from one place - now that we have teenagers, they do roam around at night and I often comedown in the morning to see every light left on...

No idea on what causes noise but in that room, as the duct is shorter the vent is not very open to balance the airflow. My system is quite lopsided as the MVHR is in the basement plant room on one side of the house, our bedroom is two floors directly above that but we have rooms at the far end of the house with considerably longer duct runs. Made it fun to balance but I got there in the end. Really interested that you found the 'in plenum' foam reducers, they may be an even cheaper place to start for me so I've pinged BPC to get one. My unit mounted to a 300mm thick RC wall so no sound transference there but I have no other sound reducing elements and I only have a hum in that one vent.

I decided to wait and see on silencers, never specced any in the original plan. MVHR unit is in basement plant room so plenty of space to retro fit one there - would be on the 160mm fresh supply port of MVHR, not the specific flexi as I probably don't have access to that anymore. Not sure why that port is particularly troublesome - all I can think of is that it's on the same side of the house as the MVHR (wasn't able to centrally locate) so the pipe run is relatively short compared to others. Also, as it's running along roof joists and not pozis, it needed to run laterally in the ceiling void to the eaves and then cut back, so maybe the relatively tight bend at that point is causing an issue. Almost (but not quite) motivated to crawl into the loft eaves to check, but pretty sure I boarded over that bit to enable storage

I've been meaning to retrofit a silencer on my BPC installation as there is just one supply vent that we get noise from and it would be the one above my bed Low drone normally but increases noticeably when on boost, especially at night when house is quiet). The flex silencer you detailed above looks like a cheap punt and will be easy to install. Will be ordering one this week!

My BCO was happy with pictures of work done if it needed covered up to move ahead with the job. We did a full new build and he only came to site four times (fouls, foundations, first fix and final inspection). Obviously a fan of the letter F.

Ask him what colour it should be. Blue is the heavy soundblock, pink the fire retardent, green moisture resistant and grey standard. From memory they were all 12.5 mm thick so you could mix and match easily.

BPC supplied my system, I found their design ok but they compensated by specifying extra duct (rigid and flex) to give me some flexibility on final layout. As their design service is free, I wouldn't expect too much from them vs a supply and install firm (who will charge you handsomely). Some other comments: I wouldn't put the plenums in wardrobes unless they have suitable gaps to maintain airflow. You typically need a 760mm2 gap at the bottom of each door in a room where there is supply or extract to allow the necessary airflow - remember that MVHR systems are barely noticeable when in normal mode and only marginally more so when in boost mode so any obstruction will just impede the air flow in that room and unbalance the system. We must have got the premium plenums (don't remember a choice) and they were very robust with mounting points and easy to use clips to secure the flexi duct. Buy a can of WD40 Silicone spray as that's essential to get duct with a washer deep enough inside the plenum to secure - it is a very snug fit and easy to kink the washer if too much friction. The flex duct still has a reasonable bend radius and it can be a challenge to get lots of connections made to the distribution box in a small space. My system, installed in a new build, took quite a bit of trial and error to get right, especially when many ducts started to congregate through a small opening (my fault for not making provision in the initial building design) but I got there in the end. My install strategy was to position the plenum and then run the duct from near the distribution box to the plenum, trying to minimise sharp bends as much as possible. When all ducts were in place I started offering up the duct to the distribution boxes and carefully trimming to get good connections with out there being too much excess duct pushing against the boxes. A bit of slack is welcome in case you over trim a duct and need to free up another 20mm or so. I didn't have much option on routing the steel duct and had to get creative with the various bends and spacers to navigate them through floor joists etc. Tip there is to work backwards from your external and remember to leave enough space between the duct and wall or in wall / floor penetrations for the lagging (thicker than you think). For complex joints, I secured up the bends and straights with masking tape until I was completely happy, marked up the pipes with sharpies and only then used the bonding compound and silver tape to make the joints final. Balancing was easy enough once I got a loan of the tool - tbh I did this almost two years after install just to get BC signoff and can't say I really noticed the difference in performance!

Our house aspect is east (street) / west (garden) and north and south face neighbours so minimal glazing on those aspects. We have external blinds to all our east facing windows and they are a godsend (even the Velux). Really keep the house from over heating year round and are great for privacy too = also no need for curtains On the west side, we have interior blinds on the loft velux, traditional curtains on rear bedrooms and have some lightweight material drapes on our downstairs sliders which do a decent enough job of minimising evening solar gain in summer. One rogue window in the kitchen faces south and we didn't spec a blind as we figured it would never get that much direct sun due to neighbours property. However the sun is low in spring and autumn and causes a localised hotspot via that window, planning to retro fit a blind when the render gets replaced at some point (another story).

We got through the whole demolition and basement construction phase with no noise complaints, also had 73 20t truck loads of spoil over 3 days and heavy plant on site and a concrete pump running into the evening waiting for the last load for the slab. However I remember the day MBC started, was a Friday in November. There'd been a minor cockup on steel lengths so the pockets we'd cast into the basement walls were 20-30mm too small so the team had to get hold of a kango at short notice and widen the pockets. At 6pm, one of the lads was knocking the remaining (and single) vertical steel into place (again, slab was slightly proud so needed some 'persuasion' and it was ringing like a gong - cue some local pull up and threaten all sorts if he didn't stop. As we had quite a sizeable crew on site that day I think he realised he'd bit off more than he could chew and left pretty sharphish.

Will that be designed and signed off by an engineer with liability insurance? Will it prevent the house moving if the front bank collapses in heavy rain? Will the house insurer agree to that not invalidating the insurance? If the house is still mortgaged, you will may need to inform them also.

We also don't have any heating upstairs but have a separate wet circuit for the towel rads in each bathroom with a separate channel on the controller. In the grand scheme, this should not be expensive and you will want independent control of that circuit as you will not want it on in summer but will want DHW circulating for washing. We also have electric wire ufh in the tiled bathrooms but this was an afterthought just after first fix. TBH the towel rads are only on over winter - rest of year they're just towel hangers and due to MVHR, towel dry very quickly.

The old saying 'Why does a dog lick its own * ? Because it can." springs to mind

I recall that others used reclaimed, cleaned railway ballast if that is cheaper. On our build, SE specced that Type 1 needed to be compacted in 150mm layers - in the end we had a single 150mm layer of type 1 at the bottom of our basement excavation (was poor quality crush with lots of visible cr@p like taps, plumbing, wiring & timber but only discovered that when it was placed and compacted). We ended up using large clean stone to backfill the basement as it didn't need compaction although the contractor obviously skimped on one area (the one week I was away from site and didn't see it go in) and used excavated spoil as it sank quite dramatically, probably 50cm over a 3m depth. So compaction is quite important!

Fair enough - just be wary of falling into the trap of an architect designing you a nice house that you get planning for and then discover it needs lots of re-design to be buildable (either budget or performance). We had 3 passes at planning to address issues, some were minor but it costs every time, even for NMAs. Your architect should really take some of this into consideration at the design stage tbh but sounds like you've given it some thought. Would be interested as to why your basement may be a planning issue. Our LA did not blink when we added a full footprint basement as the only visible element were light well grilles flush with the paving - may depend on what purpose you label them as fulfilling - ours was simply shown as a large open plan space labelled 'basement' and we later subdivided it into a gym, games room and kids dens. BC were more interested if it was designated habitable space to ensure there was the necessary fire safety measures etc.

Looks great - two comments: I am a big basement fan and against all advice (architect etc) we incorporated one into our new build and it's a great space. So open offer to pick my brains along with other here who have done similar. I will say that the basement footprint is not clear from your drawings - getting that right can have a big impact on cost. That glazing looks great but cost aside, have you modelled the impact on overheating? Even if you dot aspire to passive or SAP A levels of insulation and airtightness, a well build structure to even the minimum standards can still massively overheat in spring, summer & autumn. Before you get too deep into planning, make sure the house will be comfortable to live in!

We built an insulated RC basement with a MBC timber frame on top. Substrate is clay on river gravel on chalk. Chalk is not good as it's soluble, soft and can have 'solution features' - fancy word for holes. So the raft needed to be self supporting. We did two passes of ground investigation and SE specced a 300mm thick RC flat slab sitting on 300MM EPS200. Point loading was within published limits. As we went for an 'open box' with suspended timber floor on top, the walls needed to be 300mm thick as they acted like cantilevers. 16t of steel rebar in the finished basement which is 11.5m x 10.5m (and a small pokey out bit for plant room). 49 blocks of 300mm EPS 200 to cover the footprint was £3.6k ex VAT. 200mm EPS 70 for the basement walls was about £1.2k I think (and I ordered too much, had about 10 sheets left over, some went under garage slab, some is under the kids summer pop up pool). To match up with the passive spec MBC design, we needed a continuously insulated envelope. If your slab sits direct on ground then you will have an uninsulated cold bridge where the concrete in your ICF walls meets the slab. Not sure what this means in practice.

Yep, I think the planner's issue was overlooking, as there's no means to enforce privacy to the sides. Our rear bedroom balconies had to have full height opaque glass to each side that faced neighbours. We don't use them probably because they face west so are in shadow in the morning and in the evening we're downstairs and then go to bed. They do break up what would otherwise be a flat rear wall at the back of the house and do look pretty from outside but they were a constant pain in the build and the final suspended alu deck with composite planks and glass hung off the deck was not cheap - my fault for overlooking specifying sufficient anchoring area for the glass (GRP roof so cant drill into it). Anyway, maybe some day I'll stick a table and chair out there and enjoy the evening sun...

They say the same about us Jack

SE does not need to be anywhere near your location to offer service. We used a Bath based firm and we're 100m away in Berkshire. They came to site once but even that was not really necessary. They will base their work off a survey / GI report that they can help you design if you have not procured one already.

We considered them for our rooms in roof. Quite expensive and IIRC not available in the triple glazed near passive spec (prob quite leaky from an airtightness perspective also). Anyway, planners explicitly outlawed them in the approval conditions for privacy reasons. We went with a very large top hung Velux in each room (SK10) and are very happy with it. Based on my experience with the first floor bedroom balconies, the balcony function would never have got used.

As a teenager I once jumped into the path of an oncoming bus to try and get away from a wasp. Managed to jump back but it was an irrational fear. Maybe someone he knows has passed this on or he's had a fright from a wasp / bee encounter? My teens are being phobic about spiders at present. I love spiders. Have asked them not to make me choose...