Just started a self-build in Dorset. Exciting times!

[BotusBuild]

11 minutes ago, NailBiter said:

building control sign off for each section presuming that section is complete

You can go down the LA BC route (Local Authority Building Control), in which case I recommend going and having a chat if you can to get their guidance.

 

Alternatively you can choose a private BC company. Again, talk to them to find out how they operate.

 

Whichever way you go, it may influence how you proceed.

[joe90]

I used the local authority BI and he was great but It’s potluck, no consistency with others I have used.

[Thorfun]

2 hours ago, NailBiter said:

I hear you and I'm also nervous my arrogance is overwhelming my better sense. I believe I can make a fairly cohesive argument for what, how and why.

My understanding (which could be wrong) is that I can get building control sign off for each section presuming that section is complete (e.g. I can't get sign off for a bedroom that accesses off a landing with no bannisters put in).

I think a lot of the stress of doing bits yourself is when you are forced far outside your comfort zone under time and financial pressure. I'm hopefully able to avoid the worst of that with the benefit of clever phasing and patience. Or so the theory goes anyway.
 

Hope you get to the finish line soon mate, wishing you all of the luck (well not all of it, I need some too but a lot of it).

if i knew then what i know now things would be different!

 

obviously, i didn't know that Putin would invade Ukraine or that material prices would keep rising which caused a massive issue for us. Also i didn't know how long things would actually take. when people say 'things take longer than you think' they're right!

 

i can't comment on your BC plan and it might be best to get confirmation from a building control authority before you proceed with your plan. there's also the VAT to consider if you're doing it piecemeal as you only get one vat reclaim and doing it in stages could give cause for HMRC to reject your claim if you've been living there for many years before the next stage is done etc. all these things need considering.

 

Also, if it takes the 10 years you're thinking then how will things change in 10 years. i hate to be callous but will those elderly relations still be with you in 10 years? i speak from experience as we planned an annexe to be built post build for my mum to live in but she didn't even survive long enough for us to start the build. live tends to get in the way of all your best laid plans.

 

i do wish you all the best of luck. i can only explain the issues we had and our house is only around 420m2!

[SteamyTea]

Welcome

 

I have kept out of this so far, more out of idleness than anything else.

 

  

On 29/02/2024 at 11:38, NailBiter said:

we have designed an utterly massive house

Does it really have to be 1200+m², could get 24 of my houses in there.

 

What would be my biggest concern is the financial risk you are taking when you order the ICF.  Is the agent you are dealing with large enough to deal with this?  What happens if they vanish?

 

A year ago we had a new member who was full of enthusiasm for his ICF build near me, the supplying company went bust on him and he has since vanished.  I can only assume that he is resaving some cash to start again.

 

 

[NailBiter]

21 minutes ago, Thorfun said:

 

obviously, i didn't know that Putin would invade Ukraine or that material prices would keep rising which caused a massive issue for us. Also i didn't know how long things would actually take. when people say 'things take longer than you think' they're right!

Ouch that is unfortunate timing! Price rises are inevitable going forwards, the world is less at peace than it was before. This is why doing to big work up front whilst it is still affordable to do so. Instead of building whole phases entirely I want to first fix every phase at once.

 

24 minutes ago, Thorfun said:

i can't comment on your BC plan and it might be best to get confirmation from a building control authority before you proceed with your plan. there's also the VAT to consider if you're doing it piecemeal as you only get one vat reclaim and doing it in stages could give cause for HMRC to reject your claim if you've been living there for many years before the next stage is done etc. all these things need considering.

This is a very valid point, cheers, I'll check into it a bit more. The VAT exemption seems to mainly apply to things you'd do before first fix or materials (which I have plenty of room to store although not sure if that would be ok, best check).
 

 

25 minutes ago, Thorfun said:

Also, if it takes the 10 years you're thinking then how will things change in 10 years. i hate to be callous but will those elderly relations still be with you in 10 years? i speak from experience as we planned an annexe to be built post build for my mum to live in but she didn't even survive long enough for us to start the build. live tends to get in the way of all your best laid plans.

I'm sorry to hear that, something similar happened with our neighbours. I'm aware of the risk and the house has been built to sustain 3 generations in a cyclical way.  As the annexe becomes unused there will likely be teenagers keen on having their own privacy. If the housing market doesn't improve soon they will likely be part of the boomerang generation. As you can imagine in a house that large there is plenty of flexibility and all of us are used to living in houses in various states of repair.

Thanks for taking the time to share your experience it is very much appreciated.




 

[DamonHD]

We have 4 of us in < 80m^2, so maybe you're going to be heating and maintaining an order of magnitude more conditioned space than makes sense, for the planet?

 

Rgds

 

Damon

[Moonshine]

23 minutes ago, SteamyTea said:

A year ago we had a new member who was full of enthusiasm for his ICF build near me, the supplying company went bust on him and he has since vanished.

 

Well he posted in February, so hopefully he has found a way to progress, though not sure what came of the ICF issue, or can't comment on it if there are legal things going on.

[NailBiter]

14 minutes ago, DamonHD said:

We have 4 of us in < 80m^2, so maybe you're going to be heating and maintaining an order of magnitude more conditioned space than makes sense, for the planet?

 

Rgds

 

Damon

Majority of the house is earth sheltered so this is less of a concern. We will also have a very large solar array and everything is electric. The main trick is to ensure everything is a deferred load and that we have a lot of thermal mass to reduce temperature swings.

We originally specced a ground source heat pump but with modern high quality ASHPs, a MVHR, a passivhaus certified architect, good glass and 0.15 U-rating the calculations seem to say that this is totally unnecessary. I suspect once you look at it per person we will be above average efficiency.

Yes we do have a lot of embedded carbon in the build due to all the concrete and ICF but our house will last 100 years (I'm currently writing this from a house that was built 125 years ago) unlike the 30 year life span given with some of the other approaches (e.g. SIPS, stick built etc)

Also don't forget some of the spaces (e.g. workshop, garage, courtyard, terrace) aren't heated (or are barely heated in the case of the workshop). That figure includes everything included in CIL

Edited March 1 by NailBiter

[Alan Ambrose]

>>> thermal mass 

 

The thought police will be along presently . You might get away with it if you quickly amend to thermal inertia, but maybe not...

[NailBiter]

32 minutes ago, SteamyTea said:

Does it really have to be 1200+m², could get 24 of my houses in there.

 

What would be my biggest concern is the financial risk you are taking when you order the ICF.  Is the agent you are dealing with large enough to deal with this?  What happens if they vanish?

 

A year ago we had a new member who was full of enthusiasm for his ICF build near me, the supplying company went bust on him and he has since vanished.  I can only assume that he is resaving some cash to start again.

 

 

It doesn't have to be but we believe we have good reasons to build it that big.

Good tip on the ICF counterparty risk, I believe we are fairly well covered as we are using one of the big suppliers so the funds will only be sat with them for a very short period (less than 24 hours hopefully) before we take delivery of the blocks. I'm also told they have a whole yard full of the stuff if we need

Edited March 1 by NailBiter

[SteamyTea]

14 minutes ago, NailBiter said:

thermal mass

Really.

Works well in a cold house.

14 minutes ago, NailBiter said:

0.15 U-rating

That isn't particularly good.

 

15 minutes ago, NailBiter said:

Majority of the house is earth sheltered so this is less of a concern

See above.

 

10 minutes ago, Alan Ambrose said:

thermal mass 

 

The thought police will be along presently. You might get away with it if you quickly amend to thermal inertia, but maybe not

The zombie unit that will never die.

[saveasteading]

3 hours ago, NailBiter said:

I can get building control sign off for each section

But beware of signing off too early and not getting the VAT reclaim on the rest. They only accept a single claim.  AND remember the VAT for cashflow if the project is done in stages.

The BCO may well be sympathetic and find a way to let you live in a bit of it without giving full sign-off.

[gavztheouch]

Embodied energy is the big one when it comes to the battle against climate change. The next 10 years will be critical so even if your house was to last 1 million years it won’t matter if we all build with high embodied energy because we will have already crossed tipping points.

 

A stick built or straw bale house will last well over 100 years. If you build it in a way that can be repaired it could last forever.

[DamonHD]

My house (EPC A rated) has done nearly 60 years so far.  Stick built.

 

Rgds

 

Damon

Edited March 1 by DamonHD

[SteamyTea]

13 minutes ago, gavztheouch said:

Embodied energy is the big one when it comes to the battle against climate change.

A lot of materials are now being made with lower embodied energy than they were a decade ago.

 

I think that the two biggest things to tackle next (and fast) to lower atmospheric CO₂ levels are transport and agriculture, especially land use change.

[NailBiter]

5 hours ago, SteamyTea said:

Really.

Works well in a cold house.

That isn't particularly good.

 

See above.

 

The zombie unit that will never die.

The calculations are coming out fine, I respect your opinion but you really don't have enough info here to know if this house will be cold or not.

Thermal mass is an accepted term? https://en.wikipedia.org/wiki/Thermal_mass Splitting hairs feels like a waste of energy (pardon the pun)

[joe90]

46 minutes ago, NailBiter said:

Thermal mass is an accepted term?

Tin hat on……..

[NailBiter]

Probably best I subtly steer the thread away from what sounds like an old debate.

In any case as with any primarily solar powered house the issue is you can only generate when the sun is out and December / January is hard to get through without slurping on the grid (which I'd rather avoid if possible).

My goal is to be able to store as much energy as possible. Chemical batteries will only get me so far, storing heat is significantly more efficient. In an ideal world I'd have some sort of inter-seasonal heat storage but the house can perform that role to an extent.

Our architect seems significantly more worried about overheating, I'm personally not because if it is sunny enough to overheat it is sunny enough to generate plenty of power for cooling. 

I'm told no chance of a wind turbine due to nature of the plot but I think attitudes to this will change, particularly with horizontal ridge mount turbines.

 

Edited March 1 by NailBiter

[Iceverge]

Welcome to the forum. 

 

We moved from a 60m2 cottage to our 180m2 new build and really missed the proximity of everything.  

 

Have you done a survey on your daily movements in the house. EG how  many times you go walk from the fridge to the TV to the toilet to the bedroom. 

 

I think you're going to need bicycle lanes to make it work . 

 

 

 

 

[NailBiter]

1 minute ago, Iceverge said:

Welcome to the forum. 

 

We moved from a 60m2 cottage to our 180m2 new build and really missed the proximity of everything.  

 

Have you done a survey on your daily movements in the house. EG how  many times you go walk from the fridge to the TV to the toilet to the bedroom. 

 

I think you're going to need bicycle lanes to make it work . 

Thanks  Glad you are all moved in and happy even if your step count has increased somewhat. 

The nature of my job means I am quite sedentary so I'm looking forward to the workout. None of us are getting any younger so we could all do with a good bit of exercise! Now where did I leave my phone again ....

All joking aside you raise a very valid point, don't forget we are effectively 3 separate families living under 1 roof and we all want garage parking.

Divide our square meterage by 3 and you still get a big number (400m2) but not an aggressively big number.

In truth I've always been envious of the way our American cousins live particularly their homesteads. That was very much the space goal for us. I know that makes us different to many on here but that's part of the fun of self building right?

[Iceverge]

27 minutes ago, NailBiter said:

Thanks  Glad you are all moved in and happy even if your step count has increased somewhat. 

The nature of my job means I am quite sedentary so I'm looking forward to the workout. None of us are getting any younger so we could all do with a good bit of exercise! Now where did I leave my phone again ....

All joking aside you raise a very valid point, don't forget we are effectively 3 separate families living under 1 roof and we all want garage parking.

Divide our square meterage by 3 and you still get a big number (400m2) but not an aggressively big number.

In truth I've always been envious of the way our American cousins live particularly their homesteads. That was very much the space goal for us. I know that makes us different to many on here but that's part of the fun of self building right?

 

The wonderful thing about living in the free world is that it's your money, you earned it, spend it as you please! A fact sadly not celebrated as much in the old world as by our new world cousins. 

 

Some plans might help the collective masses gather our brains around the plan. I wish I'd put mine up,  lots of good advice I might have received might have saved me lots of hassle! 

 

 

Edited March 1 by Iceverge

[Nickfromwales]

1 hour ago, NailBiter said:

Probably best I subtly steer the thread away from what sounds like an old debate.

In any case as with any primarily solar powered house the issue is you can only generate when the sun is out and December / January is hard to get through without slurping on the grid (which I'd rather avoid if possible).

My goal is to be able to store as much energy as possible. Chemical batteries will only get me so far, storing heat is significantly more efficient. In an ideal world I'd have some sort of inter-seasonal heat storage but the house can perform that role to an extent.

Our architect seems significantly more worried about overheating, I'm personally not because if it is sunny enough to overheat it is sunny enough to generate plenty of power for cooling. 

I'm told no chance of a wind turbine due to nature of the plot but I think attitudes to this will change, particularly with horizontal ridge mount turbines.

 

You can say "Thermal Mass" as many times as you want, it's fine; we all know what we mean / what is meant / time to move (not necessarily swiftly) on....  

 

Becoming energy rich in the summer will allow you to 'bank' for the winter, so a well-performing dwelling will still be manageable in terms of energy / costs aka "green credentials". Solar plus batteries here should be a no-brainer, but even without these a heat-pump based space heating system will make running costs 'acceptable' vs the alternatives. Maybe sacrifice the renewables at the outset to get more spaces with plaster & paint + floor coverings, and just cable for the solar et-al during 1st fix? 10 years is a long time to be looking at very unfinished areas, plus the cost of the renewables buys a lot of m2 of boards etc. Your choice of course, just saying...

 

Airtightness will be of paramount importance with a dwelling this size, but you will need a very good 'team' around you to design out the multiple function living modes of this arrangement (I'll call it that vs a house, if I may  ). Having a passive raft or similar long thermal time constant store and 'emitter' will offer huge dividends, so avoid skinny screeds over insulation wherever possible; another place to 'bank' cheap energy.

 

Your architect is a good sort, as ploughing loads of expensive resources into cooling is the anti-energy efficient model you crave. Having a considerable cooling demand is way worse than a massive heating demand, IMHO, as I would much rather be slightly cold than slightly "too warm"; you can get cozy but you cannot escape excess heat. Consider solar-reflective glazing, or even better, solar (external) blinds / shutters. The latter will massively reduce summer overheat issues but will retain maximum solar gain for the winter months.

 

As far as construction method I am a huge fan of Nudura, and it was a no-brainer for the build I am undertaking this year (for a client); 1800m2 over 4 stories (580m2 basement + GF, FF, 2F) and as you say, getting smaller as it rises. You have (again IMHO) chosen well there, for this particular instance. However, with the way it sounds like you're 'arrangement' is set out, do not discount timber frame above ground. MBC's twin-wall frame with blown cellulose is a fantastic solution, with outstanding acoustic deadening / great levels of insulation to boot. I am not a fan of SIP's at all, and would have this as a budget driven, last option. Horribly acoustically transparent. Please avoid this for your roofs wherever possible.

[Nickfromwales]

3 minutes ago, Iceverge said:

Some plans might help the collective masses gather our brains around the plan. I wish I'd put mine up,  lots of good advice I might have received might have saved me lots of hassle! 

Amen.

 

@NailBiter, chop chop!!!!

[Nickfromwales]

6 minutes ago, Nickfromwales said:

Airtightness will be of paramount importance with a dwelling this size, but you will need a very good 'team' around you to design out the multiple function living modes of this arrangement (I'll call it that vs a house, if I may  ). Having a passive raft or similar long thermal time constant store and 'emitter' will offer huge dividends, so avoid skinny screeds over insulation wherever possible; another place to 'bank' cheap energy.

I meant to wrap this up by saying your airtight envelopes will be a little convoluted maybe, so MVHR (and this important source of heat recovery) will need serious planning and a LOT of forethought  I hope your team have good M&E roots!

[NailBiter]

On 01/03/2024 at 23:14, Nickfromwales said:

You can say "Thermal Mass" as many times as you want

Thermal mass, thermal mass, thermal mass!
 

 

On 01/03/2024 at 23:14, Nickfromwales said:

Becoming energy rich in the summer will allow you to 'bank' for the winter, so a well-performing dwelling will still be manageable in terms of energy / costs aka "green credentials". Solar plus batteries here should be a no-brainer, but even without these a heat-pump based space heating system will make running costs 'acceptable' vs the alternatives. Maybe sacrifice the renewables at the outset to get more spaces with plaster & paint + floor coverings, and just cable for the solar et-al during 1st fix? 10 years is a long time to be looking at very unfinished areas, plus the cost of the renewables buys a lot of m2 of boards etc. Your choice of course, just saying...

This is very much the goal, trying to avoid chemical batteries for now as the price of lithium batteries is set to continue falling.

https://rmi.org/the-rise-of-batteries-in-six-charts-and-not-too-many-numbers/ 

A 114x 600watt panel solar array (not including fixings but including cable, optimisers and inverters) is only around £12,000 which would be paid for within 2 or 3 years by the bills we don't have to pay let alone anything we can export in summer. The issue with solar is not installing it has an opportunity cost. That said the cost of solar has decreased a lot lately which offsets it.

Without a battery and with usage roughly estimated it would look something like this:

 

With deferrable loads it should be possible to use a lot of the power as we generate it and worry less about storing it in electricity form. I intend to use a tool called EMHASS to manage these loads (https://github.com/davidusb-geek/emhass) There are also some interesting tricks others have used such as putting an ASHP outside unit in the sunshine and using it during the sunny parts of the day.

I grew up on a building site (family ran a small building company) so I don't even really see unfinished rooms when I'm walking through them. Floor coverings are easy as it will be some kind of floated monolithic floor covering throughout the whole house. No fancy tiles here.

 

On 01/03/2024 at 23:14, Nickfromwales said:

Airtightness will be of paramount importance with a dwelling this size, but you will need a very good 'team' around you to design out the multiple function living modes of this arrangement (I'll call it that vs a house, if I may  ). Having a passive raft or similar long thermal time constant store and 'emitter' will offer huge dividends, so avoid skinny screeds over insulation wherever possible; another place to 'bank' cheap energy.

Agreed, our guys are currently targeting 5 ACH, do you feel that is reasonable? I had a long call with the architect yesterday and they seem to be suitably concerned about the MVHR and how the ventilation will work. We do need a really good engineer though, can you recommend one?

Definitely looking to bank cheap energy inside the thermal mass of the building. Insulated concrete raft would be great but we may have issues with heave on the site due to the mature trees and brackish clay. Will know more when we get the full report back. Good tip on avoiding skinny screeds cheers.
 

 

On 01/03/2024 at 23:14, Nickfromwales said:

Your architect is a good sort, as ploughing loads of expensive resources into cooling is the anti-energy efficient model you crave. Having a considerable cooling demand is way worse than a massive heating demand, IMHO, as I would much rather be slightly cold than slightly "too warm"; you can get cozy but you cannot escape excess heat. Consider solar-reflective glazing, or even better, solar (external) blinds / shutters. The latter will massively reduce summer overheat issues but will retain maximum solar gain for the winter months.

He really is! I'll pass along your compliments. Agreed re: getting cold and getting hot. There are also rooms we want cold (e.g. gym, larder). We have extensive glazing so a design goal from the beginning has been insulated thermal shutters on the outside of every single window. That way we can have our cake and eat it, in the winter we get solar gain all day and trap the heat in at night, conversely in summer we can do the opposite.

 

On 01/03/2024 at 23:14, Nickfromwales said:

As far as construction method I am a huge fan of Nudura, and it was a no-brainer for the build I am undertaking this year (for a client); 1800m2 over 4 stories (580m2 basement + GF, FF, 2F) and as you say, getting smaller as it rises.

We spent far too long looking at various ICF systems over a period of years. Firstly fell for the Durasol / Mineralised block marketing and then came to understand more about cold bridging and the other issues they have.

We looked at sheet based systems like Polar Wall. In the end it came down to Nudura having a good product, good support and the Fell Partnership being just up the road for us. They have trained most of the teams in the area, they started as fitters themselves and are now suppliers and they keep a lot in stock.

As soon as we met our build team that work with Nudura it was love at first conversation. They are ground workers originally but now have 4 concrete trucks and a number of site running. We knew instantly these were the guys to get it done. I'm sure as your clients would have had a similar realisation as you seem incredibly capable.

 

 

On 01/03/2024 at 23:14, Nickfromwales said:

You have (again IMHO) chosen well there, for this particular instance. However, with the way it sounds like you're 'arrangement' is set out, do not discount timber frame above ground. MBC's twin-wall frame with blown cellulose is a fantastic solution, with outstanding acoustic deadening / great levels of insulation to boot. I am not a fan of SIP's at all, and would have this as a budget driven, last option. Horribly acoustically transparent. Please avoid this for your roofs wherever possible.

Thanks, lots of the credit to our architect though but I did push for some of it. You have raised a really interesting point regarding MBC twin wall which I raised with our architect. He has a meeting arranged with them tomorrow to go through our plans.

I really really appreciate you taking the time to post. You may have saved two stories at 42m x 10m from being built out of ICF and all the embedded carbon that entails. Obviously it will come down to cost, time and other factors but if we can do right by the planet and right by ourselves we will definitely do it.

I'll keep you updated and I'll get some floor plans posted (we are making some tweaks for now so no point posting yet).

Good luck with the rest of the week!

Cheers
 

Edited March 5 by NailBiter