Self Build in Northumberland - odds stacked against us!

[charlieroper]

Good morning everyone, 

 

My wife  and I (and our 1 year old and 3 year old) are embarking on a  stone barn conversion + extension  in Northumberland. It's been a long process already (first sat down with the architect 2 years ago!) but we have planning, have satisfied our pre-commencement conditions (3 of 21 conditions in total 🫠) and in are now in negotiations with a contractor following a tender process. The tender replies were pretty wild, coming in anywhere from 50% to 150% above our expected cost so we've been busily cutting everywhere we can and hope to be very nearly there....

 

Yesterday saw a new spanner enter the works with the news that we will need a new connection from the DNO (would need it anyway but  we are installing PV array, GSHP, EV charger etc so doubly important) which is how I came across with extremely helpful community so thanks for the help already and thanks in advance for your wisdom on the stupid questions I'm sure I will be asking!

[nod]

Ask the contractor if you can go and see a recent previous job 

The difference in finish can be pretty obvious and it’s not always the most expensive that’s best 

[Jenki]

GSHP is expensive, you could look into ASHP and possibly save ££.  If a GSHP will work so will ASHP, if it wont then you need to look at Airtightness and Insulation, this is in essence a new build, and passive levels should be your priority.  Good luck. 

[Iceverge]

Firstly Welcome welcome!

 

Congratulations on the planning. 

 

Secondly STOP! 

 

Hit the brakes for a minute. Please post the spec sheet of the build and some de-identified drawings. I can already see a £10k saving from your first post. I suspect collectively the "hub" can save you much more. 

 

Thirdly, be realistic with your budget and labour. You have a young family, time is precious with them. Overcommitting yourself financially and in terms of time will make the build miserable and home life strained. 

 

Good luck!

 

[MR10]

6 minutes ago, Jenki said:

GSHP is expensive, you could look into ASHP and possibly save ££.  

+1 to this

[AppleDown]

Also get that DNO estimate in ASAP - I had the shock of my life when it came back at £70k the other day. Granted it was for three-phase, but better to be safe than sorry!

[saveasteading]

1 hour ago, charlieroper said:

are installing PV array, GSHP, 

On who's advice?

GSHP is very, very unlikely to be a good idea. ASHP is normally favourite.

PV takes a lot of cash at the worst time. Design for it being added later. Delay it. 

 

Our family has just converted a stone farm building. A steading. 600mm thick walls with no foundations.

There is a lot to learn. I've been in construction all my working life and still had to learn an awful lot.  Not all bad I should emphasise.

Any designer you use must be able to show you similar pronects or they are just playing with your money.

We found one knowledgable contractor but couldn't afford him. So your highest quote might be the most realistic, sorry.

 

We are all here to help.

[charlieroper]

Thank you everyone - in answer to a few points:

 

17 minutes ago, AppleDown said:

Also get that DNO estimate in ASAP - I had the shock of my life when it came back at £70k the other day. Granted it was for three-phase, but better to be safe than sorry!

Yes we are on that right now, been trawling through advice on here to make sure I understand what they come back with (my guess is the 15kva transformer 100m away, serving two farmsteads, needs upgrading to more like 50kva, will definitelty need new cabling from pole to buildings to be converted (c.50m) and possibly new cables coming up the hill depending on what they are).

 

 

11 minutes ago, saveasteading said:

On who's advice?

GSHP is very, very unlikely to be a good idea. ASHP is normally favourite.

PV takes a lot of cash at the worst time. Design for it being added later. Delay it. 

 

Our family has just converted a stone farm building. A steading. 600mm thick walls with no foundations.

There is a lot to learn. I've been in construction all my working life and still had to learn an awful lot.  Not all bad I should emphasise.

Any designer you use must be able to show you similar pronects or they are just playing with your money.

We found one knowledgable contractor but couldn't afford him. So your highest quote might be the most realistic, sorry.

 

We are all here to help.

I like the idea of the GSHP due to efficiency, lower input costs and given we own land around can use coils rather than boreholes so slightly less expensive than most but I 100% hear you and this is up for debate currently. The house itself has been designed to near passivhaus standard so we're ok on airtightness and performance for each. Regards PV - we have an EV so always have somewhere to put it and given these panels are cheaper than the slate the planners have stipulated we're keen to maximise!

 

1 hour ago, Iceverge said:

Firstly Welcome welcome!

 

Congratulations on the planning. 

 

Secondly STOP! 

 

Hit the brakes for a minute. Please post the spec sheet of the build and some de-identified drawings. I can already see a £10k saving from your first post. I suspect collectively the "hub" can save you much more. 

 

Thirdly, be realistic with your budget and labour. You have a young family, time is precious with them. Overcommitting yourself financially and in terms of time will make the build miserable and home life strained. 

 

Good luck!

 

We YI esNE65 8AX.YeI

 

Our budget is not all of our money (too conservative for that!) but is the amount we feel is appropriate to spend and we are going main contractor route so I don't end up going prematurely grey and being miserable (might happen anyway though!). We're working through the spec with the architect, builder, QS and SE to make savings but will be sure to ask on here for anything we're not sure about.

[saveasteading]

3 minutes ago, charlieroper said:

like the idea of the GSHP due to efficiency,

But it is taking solar heat from the ground until it runs out. It needs suitable ground, entirely  free of shade, and they often need the ground rewarmed in the summer....by air source. 

If you have sandy soil with a moving body of water in it to replenish the heat, and in the sun...then maybe. 

Air on the other hand, keeps coming.

 

Sorry for sounding negative or critical. There is lots of bad advice out there and it can be convincing. But if you site suits it then that's another matter.

Plus. Compare the cost of installing the slinky coil and heat pump, with the simple ashp.

[saveasteading]

@charlieroper the biggest surprise to me was the difficulty of getting headroom under existing door openings. It required reducing  the floor level yet not undermining the walls which were only 200mm below ground level. Apparently this is commonly  overlooked with even some collapses.

Ours had lots of doorways. Maybe yours doesn't.

[charlieroper]

1 hour ago, saveasteading said:

But it is taking solar heat from the ground until it runs out. It needs suitable ground, entirely  free of shade, and they often need the ground rewarmed in the summer....by air source. 

If you have sandy soil with a moving body of water in it to replenish the heat, and in the sun...then maybe. 

Air on the other hand, keeps coming.

 

Sorry for sounding negative or critical. There is lots of bad advice out there and it can be convincing. But if you site suits it then that's another matter.

Plus. Compare the cost of installing the slinky coil and heat pump, with the simple ashp.

No need to apologise at all - thank you for your advice! We are on a south facing slope so would have the no shade part. We are getting some advice on this from an expert but it seems a little less black and white than I thought and perhaps an easy way to make an £8k saving!

[Iceverge]

If you're near passivhaus levels then an GSHP is the worst choice you could make. It'll never pay itself back. 

 

In fact for all but the cheapest ASHPs restive heating can be competitive for a very low energy house. 

 

 

What are the specs of your walls etc? Do you have a proposed build-up? 

 

 

 

[charlieroper]

1 minute ago, Iceverge said:

If you're near passivhaus levels then an GSHP is the worst choice you could make. It'll never pay itself back. 

 

In fact for all but the cheapest ASHPs restive heating can be competitive for a very low energy house. 

 

 

What are the specs of your walls etc? Do you have a proposed build-up? 

 

 

 

that is a really interesting point. The spec is high - triple glazing throughout and current spec is for diathonite on the old building with target U-values for all the walls of between 0.18-0.32. These might seem extreme but the brief was a very environmentally friendly home which is as cheap to run as possible...

[Kelvin]

There’s no advantage to you in fitting a GSHP. Loads of installers have pulled out of the market and are just installing ASHP now. They may make more sense in larger installations or community heating. For near passive house specs it’s a lot of cost for no benefit and more likely more downsides. We looked at it ourselves as we happened to have a spare borehole that we never paid for so I thought it might have been a way to use it. But it was still expensive, added a degree of extra complexity, was possibly too close to our water supply borehole, and we had limited space inside for the plant needed. Arguably even an ASHP was overkill for us. I heated the place for months with two small radiators. Took a while to get it up to temperature but once it was there it was fine. 

[Iceverge]

17 minutes ago, charlieroper said:

diathonite

 

Interesting. I've seen it mentioned but invariably people opt for something like woodfiber or (shudders at the thought) badly fitted PIR. Is it dear?

 

I'm guessing a wet plaster layer is your airtighess then? 

 

Does the barn need an internal timber frame to support the first floor?

 

 

 

 

[charlieroper]

1 hour ago, Iceverge said:

 

Interesting. I've seen it mentioned but invariably people opt for something like woodfiber or (shudders at the thought) badly fitted PIR. Is it dear?

 

I'm guessing a wet plaster layer is your airtighess then? 

 

Does the barn need an internal timber frame to support the first floor?

 

 

 

 

Yeah it's not cheap but it's damp proofing and insulation in one product (that is also very eco friendly) so has its appeal. We might have to down spec and go for more standard insulation options (and lose a little of the room with it) but i'd rather not.

most of the barn is one level, the only bit that is two story has existing floor joists (I think back in the day this was the farmhouse but has long long long ago been used for storing farm crap) so we shouldn't have to install any new frames, just replace what is there...

[saveasteading]

1 hour ago, charlieroper said:

diathonite on the old building with target U-values for all the walls of between 0.18-0.32. 

I didn't know this material, so thanks.

 

so have had a quick read up. 50mm seems to be the maximum but doesn't seem to provide rhe insulation you need or want.

I'm guessing it looks rustic and may crack as the building moves.

[Jenki]

2 hours ago, charlieroper said:

target U-values for all the walls of between 0.18-0.32.

These values would not pass Scotland  new build target.  Max wall is 0.15 - I think you need to push for better levels of insulation, this will reduce your heating requirements further making GSHP illogical.

IMHO You need to advise your experts, that you want to achieve  push for passive house levels of insulation and Airtightness, without the associated costs of Passive house.

I was on a tight budget, but planned to better  max U values, and achieve  1 or less ACH.  You only get one chance to get this bit correct.   I managed my goals and budget  with tweaking the design and flexibility with material selection.

 

 

[charlieroper]

12 minutes ago, Jenki said:

These values would not pass Scotland  new build target.  Max wall is 0.15 - I think you need to push for better levels of insulation, this will reduce your heating requirements further making GSHP illogical.

IMHO You need to advise your experts, that you want to achieve  push for passive house levels of insulation and Airtightness, without the associated costs of Passive house.

I was on a tight budget, but planned to better  max U values, and achieve  1 or less ACH.  You only get one chance to get this bit correct.   I managed my goals and budget  with tweaking the design and flexibility with material selection.

 

 

This is exactly what we asked for at the start and hoping we will acheive. I pulled those U value numbers from the the schedule of works the QS drew up so that might just be him using the building reg values for England but I will need to ask. 

I can't tell you how helpful/interesting this is. So much of the process so far has been a mystery to me so it's great to speak with people like yourselves and understand what's actually being proposed!

[PNAmble]

We are also Northumberland - new build Timber Frame.   Would second all the views to spend on Insulation and airtightness (passivhaus standards)  Our pre plaster board airtightness test was 0.42 and took a lot of effort on our part and the builder to get right.  Despite having a ‘turnkey’ build we have spent time virtually everyday on making sure everything is as we want it - including investing in a thermal camera to check insulation and potential cold bridges; this will be the most performant house our builder will have finished so he’s learnt a lot as well.  

[saveasteading]

35 minutes ago, charlieroper said:

I can't tell you how helpful/interesting this is.

It helps to know someone is listening and interested. 

We don't know each other and sometimes  we just possibly might not be correct on everything, but its like having 10 consultants in the room, to just interject on their specific knowledge.

Linear design is costly...client  to architect to SE to QS to builder, with any original non-optimal ideas carried through.

You can save 1/4 by getting comments and feedback early.

 

Scottish reg's for conversions have ' as far as reasonably practicable' applied to insulation and some other sections. Thus you can argue where costs are insane, or you want to retain character. English not so, and you won't know the bco's attitude until its too late. 

We plumped for a timber stud wall  (tent) inside the stone, with mineral wool. We fretted that this was losing a lot of floor area but we don't think about it now, while sipping Glenwhatsit in the cosy space.

[Jenki]

I'm quite happy to offer my insights, as I'm now sat in a warm, low cost house thanks to a lot of research, reading and input from Build hub.

My initial build materials changed considerably after my research on here, and fortunately as I drew everything cost me only time.  

[Iceverge]

4 hours ago, saveasteading said:

We plumped for a timber stud wall  (tent) inside the stone, with mineral wool. We fretted that this was losing a lot of floor area but we don't think about it now, while sipping Glenwhatsit in the cosy space.

 

What was the final wall build up you chose? 

 

[saveasteading]

600mm existing stone wall. 

nominally 25mm space but increased due to the non-uniformity.

cls stud with vapour barrier on outside. 

100mm mineral wool between studs.

vapour barrier

horizontal battens for service void.

plasterboard.

In some place with sceilings we used fibre boars instead.

By offsetting we achieve new build insulation levels.

 

some stone was left exposed for heritage/ aesthetic with bco blessing.  Again offset by extra insulation where it's easy.

[Omnibuswoman]

On 10/04/2024 at 11:22, AppleDown said:

Also get that DNO estimate in ASAP - I had the shock of my life when it came back at £70k the other day. Granted it was for three-phase, but better to be safe than sorry!

Speaking from experience, the initial DNO quote isn’t always the final cost. In my case, I was quoted around £15k to begin with. Some careful research and negotiation with the DNO saved me £14k - we paid about £960 in the end.