Indy

A long way off from actually using them (need to build the building first) but in the planning stages and wanted to see what the general consensus was. The missus is particularly keen on having an interior designer to bring the 'box' (as she calls it) to life. Having looked into it at a very cursory level, the costs aren't as eye watering as I thought they might be. You can get online designers that charge £600 or so per room to do mood boards, and I'm attracted by this approach. I would end up doing the actual sourcing and decorating myself but it doesn't seem like the worst idea to have someone do the ideation/creative part for us. Is this something you've used in the past? What's a good ballpark to pay? Does it make sense to do the whole house (300 sq m) or room by room (some rooms like kitchens/utility/bathroom will be designed separately anyway)?

Building a PassivHaus level new build (285 sq m)which will have MVHR, UFH throughout and the main house will be served by an ASHP. We also have a gym/store (40 sq m) building at the base of the garden and the plan is to have an Air/Air heat pump for the occasional use that building will get. I also want to incorporate some form of active air conditioning in some of the bedrooms and the main living areas. Is this something that can be combined with the existing systems, or are we looking at dedicated units and ducting that are specific to the air con bits only? How does this generally work with the MVHR system?

Could you expand on that? Is is related to the size of the water tank we get in the property or other issues? Planning to go 3 phase as I'll be moving to an EV when my current lease runs out, and the PV system will give me 'free charging' somewhat. Not that convinced by battery tech as the man maths doesn't seem to justify it just yet.

I'm going to make a possibly controversial statement here but the 'desire' to reduce fossil fuel usage is not really a factor at all. I am looking at this from a cost/benefit and purely economic perspective (selfishly), and don't mind paying more up front to get longer term reduced bills and a more comfortable house. This responsibility that large organisations have dropped on individuals to 'reduce their personal carbon footprints' while continuing to flout all rules and lobby against real change has made me very cynical in that sense but not something to be discussed on this thread. We do have the advantage of having mains gas there already luckily, but I am considering having the connection removed/capped if we choose to go down the ASHP route for heating/hot water and induction hob in the kitchen.

Fair to say that I've used very rough and deliberately pessimistic numbers to make the comparison. Reading a few threads online does make it seem that the certified installers are jacking up prices to take into account the 5k grant, so the higher prices aren't all that unreasonable though I'll certainly be doing a lot of shopping around to get lower quotes. Given that we'll also end up adding Solar PV and if we can get the COP to be closer to 3, I can see that it makes more sense to go down this route and I guess safeguards somewhat from the eventual carbon/green taxes coming our way in the future.

Thanks for the detailed reply. I certainly haven't ruled ASHP out and its useful to read that it does still make sense. One other thing that the architect mentioned when we were in the design stage is that given our build doesn't start until after June this year, new Building Regs kick in. This would make it quite difficult to get approval for a Gas boiler anyway. We are also looking at adding Solar PV in, which means that we could potentially get a few hours (in the summer at least) of 'free usage'.

Overall size of new house is 280 sq m. 6 occupants - 4 adults, and 2 kids under 5.

Our current plans for the new build have factored in ASHP (at the recommendation of the architect) with UFH throughout (no radiators even on 1st floor). We are aiming for a PassivHaus type building with good thermal efficiency and airtightness with an MVHR system, and ASHP is something that seems to fit the bill as it's a new build and not a retrofit. However, I want to see whether the sums for an ASHP are really justifiable given the rapid increase in cost of electricity. Please bear with me as I work through my train of thought: General usage in our 1930s house (should be lower in the new house hopefully) 6000kWH of Electricity @ 28p/kWH = 1,680 30000kWH of Gas @ 7p/kWH = 2,100 Total cost = 3780 or 315 per month (ouch!) New house - keeping the same numbers for ease 6000kWH of Electricity @ 28p/kWH = 1,680 To get 30,000 kWH of heat output from an ASHP with a COP of say 2 (average across the year) = 15,000 kWH of electricity @ 28p/kWH = 4200 Total cost = 5880 or 490 per month (double ouch!) This is disregarding the capital outlay for an ASHP, which is going to be more even taking into account the BUS grant of 5k. Gas boiler = 2.5k (example) ASHP = 10-12k minus the 5k = 5k to 7.5k net I've not factored in all the gubbins like water storage as they'll be common in both scenarios. Does it make sense then to consider an ASHP? Realise both gas and electric prices are up, but the differential between them remains at 4:1 and I can't see gas going away anytime soon. A family member who works in the sector tells me about the introduction of Hydrogen into the gas mix and trials already being run in Scotland, which means there is a long term plan to continue using gas.

That's a shock. I had recently been on there training day at the NSBRC in Swindon and there was certainly no indication that they were going through such difficulties.

Yes, full demolition and new foundations to be laid as the new footprint is bigger than the existing one. Interesting that we'll need it both disconnected AND reconnected. Any indications on how much this costs - is it a set/capped price or does it vary by area and council etc?

Some of it is related to the bad reputation that old electric storage heaters had, and how they weren't as effective as GCH. Would be interested to hear if people still had to pay a standing charge, even if the connection wasn't being used?

The site we're on houses a 1950s bungalow which has a gas connection (combi boiler, GCH, Gas stove in the kitchen). In our new build, we're planning to move away from the boiler to ASHP and induction hob in the kitchen (sleeker and easier to clean). What should we do with the gas connection? Is it recommended to completely get this removed or disconnected as we're not using it? Or have a connection coming to a 'box' in the property but capped off and unused? I seem to hear time and again that properties without gas are unfavourably looked upon when selling, so wanted to get people's views on this.

Fair point, a ramp or something similar for a very small drop would probably be too impractical I guess. Any comments on this idea: Vaulted ceilings in the master bedroom and front 2 rooms (to give the idea of height and counteract the sloping roofs on either side) Normal roof in the middle part of the house - this gives it a little bit of storage space (boxes, suitcases etc) and also space to vent the MVHR system Or Would you suggest going for vaulted ceilings throughout the 1st floor and using something like Posi-joists for the MVHR ducting system?

Really love this forum and all the help it affords. Having gone through a similar process myself (another thread in this subforum), I would say choose what you like best (you have to live in it and pay for it) but the suggestions from @Icevergeand @ETC are both on point. Really like the exterior above as it has a lot of symmetry.

Our wait time has gone from 4 weeks, to 5 and now between 5 and 6 weeks BEFORE it even gets in front of a validation offer, so we're a step behind you. Very frustrating but not much we can do apart from wait. No point in kicking up a fuss either that the application has to be considered within 8 weeks, as the planners can then basically reject for a flimsy reason and put us in the queue for appeals (which tend to take upwards of 6m anyway). To be fair, some of the quotes have also included further quotes in the appendix from the likes of Rationel for 3G Alu-Clad timber windows and sliding doors. A number of pages are dedicated to these specs and designs, but its still a huge amount of information to take in and I've now made a start. Also chased up my ICF contractor again and he's promised to give me some info by the end of the week, fingers crossed!

It was the Arkiplan number that I found to be quite high (used their instant online quote), didn't go as far as sending Draw+Plan anything via email as I'm sure we will use our architects anyway. Happy to share their details via PM, no complaints from me apart from the design process taking longer than I had originally envisaged. That's more down to the number of different directions we went (refurb, new build, changing exterior finishes etc). They've certainly been quite patient given everything.

Any more views on lowering the overall floor of the house, or shall I take it that this is a bad and potentially expensive idea? One thing I've discovered (naivety showing here) is that you don't dig the entire plot down for standard foundations, only at the edges. So my initial thoughts of just going another 200mm lower is not realistic. To actually remove 200mm across the entire space (say 165sq m in our case) would be a much chunkier job.

Can you advise what your floor buildup looks like? Completely new area for me and I'm looking into it, but thinking of block and beam/precast concrete floor slabs with UFH. Need to understand what thickness to aim for so I can work around that number.

That is an option but would it not be better to have usable floor area compared to vaulted ceilings?

So... still no update from council on whether our application has been registered or validated, and the idle mind being a devil's workshop and what not. Was looking through my document pack and the section plan gave me some ideas. The height of the roof space above the 1st floor is 1888mm, which is too low for bedroom use. That's fine as I don't really need any more bedroom space but I was thinking whether it would be possible to create some entertainment space - cinema room, bar/whisky storage area or a games room. One option would be either to drop the height of the current floors from 2400mm to say 2300mm each and 'donate' that space to the loft space. However, a quick chat with the architect indicates that plan is not so straightforward as the space of over 2m head height needs to exist for a space of at least 900mm width, which doesn't seem doable and would mean a drastic re-design including the location of the stairs. The other option I was considering was whether we could start the house at lower than ground level by say 200mm or something similar which then gives us the internal space needed without raising the roof height, which would be what the planners would look at very closely? This would be somewhat of a compromise as I can't afford a full basement (too expensive) but wanted to see if others had done something similar and what the associated costs would be? That can then help me decide using a cost/benefit analysis if the additional space would be worth the investment.

That sounds like a plan. Any ideas on what the cost differential between concrete stairs and an oak staircase would be?

Concrete stairs - would you have this covered with a wooden one/veneers or do you mean proper concrete like commercial ones? Also, wasn’t planning on carpets earlier but LVT on ground floor and engineered wood on the 1st floor.

Currently staying in a barn conversion in the Cotswolds for a holiday, and while it's lovely and quaint - the lack of any soundproofing/noise insulation (not sure what the accurate technical term is) does drive me up the wall. Creaky floorboards Creaky staircases Can hear people talking in the room next to you Can even hear people talking on another floor The worst one - can hear other people using the bathroom on another floor! Which has solidified my decision to do as much as possible to put in the structural elements in our self build to avoid these. We will most likely end up building in ICF (Nudura blocks) but this is only for the external walls. What other things do I need to factor in for the floor, internal walls etc so that noise doesn't travel from one room to another? I visited one site where a contractor recommended Lewis deck flooring, would this work?

Don't have an answer on which way to go for you Sarah, but I did try an online quote for one of the companies you mentioned in your earlier post. They're actually coming in more expensive to do Building Regs drawings than the quote I have for my architect (which I guess re-affirms the value for money we're getting!).

Hey @SarahG. Apologies for taking so long to reply - I've been away on an early Easter holiday (still there but reading the forums). I have received a number of quotes both from Timber frame companies and also ICF suppliers (Nudura, Beco Wallform, Durisol and Polysteel). However, I've not had a chance to sit down and do a proper analysis/side by side comparison of any of them for several reasons: 1. Some of the docs come in at 46 pages long - very hard to digest when on holiday! 2. The quotes are all written differently - in the sense that TF ones usually take you to water/airtight with the full shell erected. However, the ICF ones are only for the blocks and mention ancillaries like bracing, cost of concrete, pump hire etc - without committing any costs to it. 3. I've also asked a couple of specialist ICF builders/main contractors (the route we will most likely en up taking) and have been waiting weeks for them to get back to me. Quite usual these days from what I've been told - so I shall use the receipt of the first one of these as a trigger to get my comparison sheet to TF in place. On an unrelated note - our planning application hasn't even been registered on the council website (4 weeks and counting), so we are still a long way off from having confirmation that we can build the structure we're getting quotes for!