Andeh

U value of 0.13 and 0.11 for flooring and ceilings, then 0.18 for walls seems a large step up from current which is nearly double some of these figures? Or am I reading it wrong? (page 12)

That was an avenue we are/were exploring as well. Even got a SAP done for Gas & ASHP separately....... hoping it is no longer required (much like yourself). I *think* we are in the clear...providing my/your builder is MCS setup.

Thanks J1mbo, looks like we are OK with being a new build property then, I think! (just re-read your post & good to see your agreement!!) Now I am worried if my builder, or equiv who he uses, is MCS Registered!

Has anyone seen anything official on eligibility for the £5k grant?

Thanks buzz, depth isn't an issue for us (but is for OP), so going after u value over depth. I presume EPS is less effective then PIR if it is cheaper?

Try being in a bungalow! ? I defaulted to "1" for mine, but moved it back to a mid point before linking to OP! & yes, this forum is a huge wealth of information. Always be mindful though, whilst this place is full of hugely knowledgeable & helpful people, kind enough to help & advise others... Don't forget most of them are also enthusiasts! Where their "normal" is a loooong step away from normal normal. I live my life on here trying to achieve better then normal, but accepting I am likely below average for buildhub!! ?

We're locked into a builder now, so there will be a kick in the teeth changing spec he has quoted against (supply & fitment) not to mention peak pricing on materials across the board.

This is a useful tool to have a play around with. 100mm is actually 0.14, vs the build regs expectation of 0.25...which drops to 0.18 in next years uplift. So, in a nut shell...100mm is still very good & will give you a very warm house. 125mm is even better....150mm even better....etc etc....hardest point with all of this is when 'enough is enough'. Calculator (uvalue-calculator.co.uk)

Yep, I'm 100% in the same situation! And fully agree in terms of the impact only increasing long term with energy prices. We have 150mm specified (0.11) but there is a £4500 saving if we brought it down to 100mm....(0.18 I think).... we'll prob settle in the middle on 125mm for a £2000 saving for use in the countless other areas I want to try and put more money into. Especially more tangible areas like wanting vaulted ceilings, bigger windows, larger sliding doors etc etc. 100mm still achieves current building regs & in my research also looks like it will still exceed next year's building regs uplift as well. As ever more the merrier & I'd love to go uber insulated... But it becomes increasingly hard to convince myself & the wife when we look at the impacted value... Hence the "maybe another £10 cheaper per month!?" As we're a bungalow, we get hit even harder on sheer surface area to bleed heat through.... And cost to try and mitigate!

125mm should get you to 0.13, 150mm to get to 0.11. Reality is in this range of insulation your spending £1000s to save £10s.

We have received the SAP numbers that are around 10-25% improved to the "high numbers" as above (current regulations), in theory averaging out to comfortably pass the June '22 (next gen regulations) numbers as well. Going a meaningful step further is a £10k bill from the builder, which we can't afford sadly! Joys of going with a large bungalow !

Thanks for the quick reply & just so I am clear ...the lower values (Wall 0.26, Floor 0.18, Roof 0.16) are the bare minimum required for new AD L - June '22? The ones our SAP report showed (0.30, 0.25, 0.20) are the current regulations?

Hi All, Just some general confirmations please! Am i right in thinking the current regs for new dwellings are: Wall 0.26, Floor 0.18, Roof 0.16? Air Permeability of 8m^3...however for the Consultation version January 2021....they are not actually changing, as they are detailed as: Wall 0.26, Floor 0.18, Roof 0.16 in this document as well? However on our SAP report he details 0.30 for Walls, 0.25 for Floor and 0.20 for roof? Can anyone unconfuse me please?

Pretty much this! If you can afford the time shop around for the cheapest & have the fallback of if cheapie quote misses something or isn't clear & clarification is required then it'll cost you a couple of weeks & top up fee potentially. We used architects recommendations, knowing they were generally more expensive then my Google-fu could find... But all were known good quality, user friendly & got us through planning 1st time. Bat's, trees, highway hurdles & all!!

Thanks very much all! Turns out SAP calculator chap used the wrong figure for the floor.... it should be 0.11, not 0.17, as designed. Jetfloor likely to be replaced as insufficient height for it, alternatives tbc to achieve this. Seems the walls are a tiny bit over as well but not massively. Roof is at 0.18 correctly. All others are assumed values for boiler (or ASHP more likely), MVHR, windows, hw tank, etc so might squeeze some extra there. We're expecting named units/known specifications in January, so will review it again then. Builder suggesting around £4k for roof top up and another £4k to beef up wall insulation to meaningful differences (ie extra 50mm+) which makes a very unappealing deal with everything else going on. We're being hammered on the price increases anyway, so one to accept as is & move on sadly. Thank you again for the feedback everyone... The joy of wanting uber grand designs on an insufficient budget!!

Also a thought for me!

So all these products are to seal the gaps between window & masonry? Is there a reason gripfil or silicone is not used to plug these gaps up? They could surely achieve a similar result & are much more readily available?

Several weeks ago, it's a large new build & what our builder would knock off if we stepped down from an ASHP. He has been reliable with other cost adjustments so I have no reason not to trust this figure within reason! ?

I'm not sure I agree with any of that! For our new build, £14k for a full plumbing + ASHP installation vs £11k for Gas boiler from our builder. Have mains gas as an option but both builder & architect strongly encouraging ASHP, hoping with the £5k grant to smooth the transition. My research suggests they are entirely appropriate for certain properties, entirely inappropriate for others - our new build being an ideal case for ASHP. Whilst no expert in heating systems, I am a Mechanical Engineer with a career in Energy Sustainability - long term Electricity is the answer -vs- Fossil fuels, from a political point of view (Russia & OPEC) from a sustainability point of view (cheap Renewables & self generation). Throw in storage & Nuclear and 'green government taxing fossil fuel' vote winning its a no brainer over the next several years. Hydrogen is a laughably hopeless cause for anything other then large industrial equipment.

Thanks all, would that reduce the SAP calculations as a result? Does sap equate for total sqm or only a sqm? Could explain why the 3 story semi we are in now is massively better on paper.

We loved our slide & hide, with built in self cleaning. We will be using them again in for sure!

Interesting! Thanks for that, something is wrong there then, as drawings state jetfloor with infill insulation & 150mm rigid insul to achieve! I'll need to investigate

Thanks very much all, some great feedback there! Am also concerned ASHP (architect & builder are grinding me down into accepting one over a gas boiler ? ) will reduce that score as well, but am led to believe ASHP will be 'for the greater good' then a Gas boiler even if the SAP score takes a nose dive. Yes, this was only the first pass so will be looking to enhance floor & roof, the walls will be tricky as we are fitting in a lot of rooms into the footprint, so internal space is actually tight (4 kids to cater for). The ceilings on the other hand are very high throughout, so less worried about build up here. The architect has stipulated a minimum of 5 for air tightness, but have read enough stories on here to know this is an area ill need to work with the builder on (and probably seek further advice here) on how to reduce this further. Jetfloor is block & beam, but using EPS insulation instead of the concrete blocks. Builder said he would use the kind that 'wrap around' the beams, but this hasn't been written down anywhere so one i am monitoring. Rest of the place is twin block wall, render outside (and some Z stone feature cladding). edit: we have some PV, but some massive trees in the garden which cast some shade, so this has been down played on the EPCs.

Just looking for general advice! We are at the foundation excavation stage of a 240sqm bungalow, after a last minute refurb --> rebuild change of plans (one of the builders had a cancellation & said he'd do a full rebuild for the price of our refurb if we fitted into his cancelled slot. He was our favoured builder by a decent chunk, so we were/are utterly delighted...but it has meant the architects & builder have had to work overtime in getting all the documentation sorted - hence adjusting insulation details after construction started) As a result, we only recently received our draft SAP calculation of 81 - which I couldn't believe. This was with 125mm full fill cavities. 250mm Jetfloor + 150mm PIR below UFH and 125mm PIR in roof space, MVHR etc - not exactly bare minimum in my mind (though I acknowledge behind BuildHub norms of Passive House standards!!), but I was still very surprised to 'only' get 81. Scores are: Ext Walls 0.22, Floor 0.17, Roof 0.18 Architects have gone away to try and get me a 10% improvement to bring it up to 88/89 (Ecology mortgage as a benchmark, though not using them). However - I looked up the 2019, 3 story, semi-detached naff Persimmon new build we are renting for the duration of the project & was horrified to see it at a 86 EPC rating. I don't quite understand how we are ''only'' at 81 in a £500k bespoke new build with (in my mind) good levels of insulation...yet a mass produced cheapie (£240k for 4 bed...) property in the same locality achieves 86. Does the fact we are building a bungalow impact EPC? Are EPC & SAP the same to compared? How does 250mm jet floor + 150 PIR only get us 0.17!? Hoping to be educated!

Following with interest, be grateful for the advice as we start our project!