Andeh

My personnel opinion...... Big builders on the mass homes work to a very standard copy & paste routine, it's factory housing done very efficiently! Therefore any slight deviation causes them significantly more effort just because of the extra admin, paperwork, ordering, checking, permissions etc behind the scenes. I am guessing It isn't as simple as a sparky nipping to screwfix, buying 8 instead of 6 and taking the £100 cash off you next day. The big-builder will have bulk ordered all the standard LEDs for that batch of housing off the generic copy & paste plans, then allocated the stock copy & paste allocation etc etc...now you want 4 more, so their central team will need to go back to their paperwork to update your specific house & confirm it can be done, then updated drawings & re-issue bespoke... then go to their approved supplier to find, allocate & track the extra few lights all the way back to your individual plot & team working on it.....for your sparky to install to updated needs. Coming from a different industry, but not totally dissimilar in principle.... we have got the art of building POSH @ cheap (without cutting quality), just down to a massively fine tuned & refined process & efficient order/speccing/management.....this is great for the 99% standard...but that 1% causes a huge amount of extra work to modify off spec.... which is why it is rarely accepted -OR- done off-factory, at significantly extra cost.

Does the MVHR not help swap the air over during the night anyway? Pump out warm air & draw in cooler external air?

I am no longer expert, but insulated / thermal plasterboard is an easy option!

Never has a job gone from fine to utter (expletive deleted)ing disaster as quickly as using expanding foam for the first time!!!

Resin fix a threaded bar into it! Just make sure you get it right the first time....once bonded in they aint never coming out https://www.screwfix.com/p/rawlplug-r-kem11-175-kit-styrene-free-polyester-resin-175ml/4100R?tc=VA6&ds_kid=92700048793290424&ds_rl=1249413&gclid=EAIaIQobChMI1KfD2vr28wIVFaWyCh2zsQn_EAQYASABEgIW-vD_BwE&gclsrc=aw.ds

How are you getting on with them? We are going for a similar setup, with a floating corner & doors that seal against each other (so no pillar) - similar overall dimensions to your though.

Looking really good - thanks for the pics!

Just to update the thread when we originally assumed 500L for 6 bedrooms (3 bathrooms)....now settled on 300L with ASHP. The higher heat loss & actual need for that volume of hot water just didn't make sense for us to go for 500L. It is a constant high thermal loss & enhanced strain on ASHP to keep it hot....for a volume of water we would use <5% of the time. 300L should cover our needs for 90% of the time, so a reasonable medium ground of cost/efficiency/need.

Very good!

This is a very good post! Sums it up well.

Thanks guys! I'll raise it with them next week. Both builder & architect have been very professional & by the book to date, so will see what they say.

Thanks for the comments guys, I'll raise it with the architect & builder (both very experienced in doing new builds) but seeing as it's all on site, kicked off & we're moved out etc... we're committed now. That being said, with it all being carried out within a continuous 8 month period, same builder, mountain of paperwork (planning, building control stating new build & demolition etc), staged payments, continuous project plan, non-occupancy throughout, I'd suggest HMRC would struggle to evidence this was anything other then that it is... A total/full knock, excavation & new build as planned/documented. Edit to add, as existing property is a 1960s timber frame & we are going over the top with block & beam, large Mono pitch etc.... There is very little we could reuse even if we wanted to.

Thanks, I figured there would be something like that that.... 6 month occupancy would be tight to cover! Was just a brainwave at 4am for me

With experienced builder & experienced architect firm I'm just following them tbh, builder is on site already. 8 months from now the existing bungalow will have been 100% demolished & replaced with a 100% new one, with all the documentation submitted to boot! Whether we do it right to left, or left to right it's still a full knock down & rebuild? Where would HMRC have an issue?

Thanks all! Our project was originally a full refurb & large extension. We got the planning permission for this. At the last minute builder advised he could do a full knock down & rebuild for the same money. We are now going down to the this route. We have just submitted a new planning application for a full rebuild... And the builder will spend the next few months starting the extension and LEAVING the bungalow until planning is in. The new build will be very similar orientation to the existing bungalow, plant room in an identical area. With the submission for RHI, what stops me installing ASHP into the existing bungalow.... Commissioning it... Getting RHI then decommissioning knock down, rebuild, reconnect... Crack on? ASHP location doesn't change, plant room doesn't change just connecting & disconnecting it from the existing bungalow? Existing bungalow, 1960s timber frame, is EPC B, 85 (epc done last year) is there anything in the RHI application that would block this?

Anyone heard anything about the grant being available for self builds? I'm still struggling to find any thing definitive!

Can anyone link to the T&cs of this please? How does this impact us self builders building a self build having already removed the gas boiler having knocked it all down? What will be the criteria to claim? I will miss RHI for a few months, was hoping this £5k would soften the blow!

Has anyone been following this? It doesn't look to be as generous as the RHI, but it is up front vs over several years! I am struggling to find details on how to claim it, what criteria though? https://www.mirror.co.uk/news/politics/homeowners-set-offered-5000-grants-25231186

Considered calor/equiv gas? With a big tank & careful buying it could be an option.

Thanks, my original hope was a way of installing the pipework & electrics for a split system... Then getting someone to simply connect it up at each end when we can afford to install it.... Is that possible?

Surely a local labourer or two (farm hand or equiv?) for a few days would be cheaper & less stress? I get the principle of the machine, but using one inside a room, I imagine 50% of the time effort will be not reversing it into/through a wall as you try to position it. £200/day for a couple of guys & barrows would be my first direction I think.

We have been spec'ed metal stud plasterboard internal walls. Architect suggests they should be fine & are more substantial then the metal stud & plasterboard walls we used to have in a 2005 Bovis 'new build', but these were so cheap & flimsy it wouldn't be hard to better...cardboard would have!! I am trying to find a more substantial internal wall, without going mad. Obviously block walls would be the best, but it needs to be cost effective! Double up CLS studs & double up plasterboard? Single plasterboard but 15mm instead of 12.5mm etc? Combination of it all? Can anyone comment on what they went with & successes/failures? Thanks,

Yes, likewise! We will suffer from solar gain due to large windows overlooking our south facing garden. Can't not do it....but will need to look at AirCon (active air & UFH passive) to reduce the impact my gut tells me.

Interesting experience Marvin, thanks for commenting!

Yes ASHP into UFH - not sure I know how that could be used to cool? MHRV designed in as well. Bungalow ceilings will all be vaulted to the roofline unfortunately!