smart51 Posted March 11, 2022 Share Posted March 11, 2022 I'm currently putting thoughts together for a future (hopefully soon) self build. I often see figures like £2000 per square metre as a guide. I assume that's for a 2 story house. How does it vary for a single story house of otherwise the same construction. So a 200m2 2 story house has a foot print of 100m2 and at £2k per m2, the build cost would be £200k. If that were a 200m2 single story house, with a 200m2 footprint built to the same standard, would would be a good cost estimate? Link to comment Share on other sites More sharing options...
Iceverge Posted March 11, 2022 Share Posted March 11, 2022 Crikey, it's a matter of determining how long a piece of string is... Broadly, the larger the floor area the more floors it justifies. At a guess, from viewing developers catalogues for one off houses with prices, < 120m2 for a single story, 120-240m2 for 2 story etc etc. Obviously if you get a superb price for foundations and roofing it sways the deal. 1 Link to comment Share on other sites More sharing options...
Conor Posted March 12, 2022 Share Posted March 12, 2022 General rule I've heard before is an additional floor to the ground floor costs approx 50% less than the ground. A bigger factor tho is economy of scale, I.e. the bigger and simpler, the cheaper. And how quickly to can build it so inflation and increasing costs don't drive it up too much. 1 Link to comment Share on other sites More sharing options...
Ian Posted March 12, 2022 Share Posted March 12, 2022 @smart51 rule of thumb is that it costs approx 15% more per square/m to build a bungalow compared to a normal 2 storey house 2 Link to comment Share on other sites More sharing options...
nod Posted March 12, 2022 Share Posted March 12, 2022 Cost per m2 will always be more for a single story compared to two story Apart from taking up more ground You are increasing the size of your foundations One of the more expensive parts of many builds We spent more than a quarter of our entire budget getting out of the ground on our previous build 1 Link to comment Share on other sites More sharing options...
Russell griffiths Posted March 12, 2022 Share Posted March 12, 2022 I would add that design is the bigger factor to cost rather than size. I think if I had changed my design, different roof, less weird angles, different materials. I think I could build my place for £100,000 less than it’s going to cost. Square box, red tiled roof, plastic facia and gutters. Probably why the developers stick to a certain design. 2 Link to comment Share on other sites More sharing options...
smart51 Posted March 12, 2022 Author Share Posted March 12, 2022 There is a plot of land up for auction that we have our eye on. It is between back gardens and allotments. My concern is that the council might impose a height limit on any development which would mean a single story building. Before we get in too deep, I want to know what that might cost. There is enough room to do what we want with a single story building but I'd prefer 2 stories and a bit more space between the house and the boundaries. Link to comment Share on other sites More sharing options...
Marvin Posted March 12, 2022 Share Posted March 12, 2022 (edited) It could be the design allows for a single story construction on the allotment side and a 2 story construction on the housing side.. With a big sloping roof... Edited March 12, 2022 by Marvin 1 Link to comment Share on other sites More sharing options...
nod Posted March 12, 2022 Share Posted March 12, 2022 If you budget at around £1500-2000 m2 build cost on good ground Plus all the usual fees Buying - Surveys Conections etc 1 Link to comment Share on other sites More sharing options...
Iceverge Posted March 13, 2022 Share Posted March 13, 2022 A basement might be an option depending on the ground conditions. I don't think they're as expensive as folk imagine. 1 Link to comment Share on other sites More sharing options...
Andehh Posted March 13, 2022 Share Posted March 13, 2022 (edited) 18 hours ago, nod said: If you budget at around £1500-2000 m2 build cost on good ground Plus all the usual fees Buying - Surveys Conections etc I think you'd be very lucky there! We are building a mid-high ish spec bungalow, 250sqm and when we got quotes last August we received 5 detailed quotes all for around £2500 - 3000psqm. That's for ASHP, MVHR, lots of big aluminium windows, big posh slidding doors, upgraded insulation etc etc. Turn key build though not inc usual fees & paperwork. We managed to get that down to around £2100 when our favourite builder (but also one of the more expensive ones) had a commercial cancellation that overlapped perfectly with our needs, so got a good deal off him, if we fitted to his time framen (which itself caused plenty of headaches) . Edit: we also assumed around 15-20% extra for single story vs 2 story. Edited March 13, 2022 by Andehh 1 Link to comment Share on other sites More sharing options...
nod Posted March 13, 2022 Share Posted March 13, 2022 It depends on how you go about your build For arguments sake If the total brickwork cost was 20k your builder will nearly double that Everything will come with a very large mark up Some friends of ours have even been charged vat on some of the work they had done while using a main contractor Our build is 416 m2 and we will complete it to a very high spec within the 350k that we have budgeted 1 Link to comment Share on other sites More sharing options...
Amateur bob Posted March 15, 2022 Share Posted March 15, 2022 On 11/03/2022 at 23:19, smart51 said: I'm currently putting thoughts together for a future (hopefully soon) self build. I often see figures like £2000 per square metre as a guide. I assume that's for a 2 story house. How does it vary for a single story house of otherwise the same construction. So a 200m2 2 story house has a foot print of 100m2 and at £2k per m2, the build cost would be £200k. If that were a 200m2 single story house, with a 200m2 footprint built to the same standard, would would be a good cost estimate? someone correct me if im wrong but its not the footprint you work costings on its the internal floorspace so if its 200m2 then at 2k/m2 thats 400k?? Link to comment Share on other sites More sharing options...
nod Posted March 15, 2022 Share Posted March 15, 2022 I think most would go off M2 that is at the bottom of there drawing Or stated on there sap Build size Link to comment Share on other sites More sharing options...
Amateur bob Posted March 16, 2022 Share Posted March 16, 2022 8 hours ago, nod said: I think most would go off M2 that is at the bottom of there drawing Or stated on there sap Build size huge difference between that and the footprint if its double storey Link to comment Share on other sites More sharing options...
Andehh Posted March 16, 2022 Share Posted March 16, 2022 On 13/03/2022 at 08:17, nod said: It depends on how you go about your build For arguments sake If the total brickwork cost was 20k your builder will nearly double that Everything will come with a very large mark up Some friends of ours have even been charged vat on some of the work they had done while using a main contractor Our build is 416 m2 and we will complete it to a very high spec within the 350k that we have budgeted With the greatest of respect though -and please correct me if I'm wrong-but I believe you are undertaking some of the work yourself? Thus giving you a greater saving on psqm cost. Most self-builders will be in the same boat as me, not able to do any work Inc project management so will need to assume full builder fees. 1 Link to comment Share on other sites More sharing options...
Ian Posted March 16, 2022 Share Posted March 16, 2022 10 hours ago, Amateur bob said: someone correct me if im wrong but its not the footprint you work costings on its the internal floorspace so if its 200m2 then at 2k/m2 thats 400k?? That's correct. Link to comment Share on other sites More sharing options...
smart51 Posted March 16, 2022 Author Share Posted March 16, 2022 15 hours ago, Amateur bob said: someone correct me if im wrong but its not the footprint you work costings on its the internal floorspace so if its 200m2 then at 2k/m2 thats 400k?? Internal floor space? I'd assumed external foot print, so including the external walls. If I have to build a single storey, there's about 10% difference, slightly more at two stories. I like errors in my favour. Link to comment Share on other sites More sharing options...
JohnMo Posted March 16, 2022 Share Posted March 16, 2022 50 minutes ago, smart51 said: Internal floor space? I'd assumed external foot print, so including the external walls. If I have to build a single storey, there's about 10% difference, slightly more at two stories. I like errors in my favour. But they are all estimated, the estimate will change hugely, based on building shape, size, build type, external and internal finish, flat roof, pitch roof, insulation levels, ventilation/ airtightness, heating type (gas, ASHP,gshp, UFH radiators) etc etc. Two different kitchen designs can change a build budget by £50k, the amount windows can change it again by £20 to 30k with ease, uPVC or Ali clad can change it again by the same amount. My thoughts are for a basic start point. £2k to £2.5k per M2 with someone else doing all the work will be a basic ok performance house, so 400k for 200m2 two storey. Add a good 10 to 15% on for single storey but depends on roof complexity (our roof added about 25% to m2 cost). The more bells and whistles and any changes you make along the way will add quite quickly. The above assumes limited or no landscaping, painted internally a single colour. 2 Link to comment Share on other sites More sharing options...
nod Posted March 16, 2022 Share Posted March 16, 2022 20 minutes ago, JohnMo said: But they are all estimated, the estimate will change hugely, based on building shape, size, build type, external and internal finish, flat roof, pitch roof, insulation levels, ventilation/ airtightness, heating type (gas, ASHP,gshp, UFH radiators) etc etc. Two different kitchen designs can change a build budget by £50k, the amount windows can change it again by £20 to 30k with ease, uPVC or Ali clad can change it again by the same amount. My thoughts are for a basic start point. £2k to £2.5k per M2 with someone else doing all the work will be a basic ok performance house, so 400k for 200m2 two storey. Add a good 10 to 15% on for single storey but depends on roof complexity (our roof added about 25% to m2 cost). The more bells and whistles and any changes you make along the way will add quite quickly. The above assumes limited or no landscaping, painted internally a single colour. Good point The amount of work that you do yourself will have a massive impact on your costings It seams a long time since we came in at 815m2 At a very good standard Something I have notice this time Planners have included our detached garage - workshop Last time while we included the material We didn’t add any m2 for the garages 1 1 Link to comment Share on other sites More sharing options...
saveasteading Posted March 24, 2022 Share Posted March 24, 2022 On 12/03/2022 at 08:09, nod said: Cost per m2 will always be more for a single story compared to two storey Ahhh, I don't think it is quite that simple. It is that word 'always'. I would agree with nearly always. For a conventionally designed house yes. When open plan or large rooms are designed then that changes because everything gets technical and heavy. Plus when you allow for the loss of useful space for the stair and the stair approaches x both floors, the useful space is reduced. This applies much more proportionally to a small house. For non-domestic, which is my thing, I would tell a client at first meeting that it was much the same cost £m2 of useful space, and the use of valuable ground might be more important. Lifts also add to the cost and loss of space. Single storey easier and safer too, as there are no holes in the floor and don't have to carry plasterboard up. 1 Link to comment Share on other sites More sharing options...
flanagaj Posted September 13, 2023 Share Posted September 13, 2023 (edited) On 11/03/2022 at 23:19, smart51 said: So a 200m2 2 story house has a foot print of 100m2 and at £2k per m2, the build cost would be £200k. It's total floor space and not just the ground floor space. You got my hopes up for a moment that I could halve the project costs! Edited September 13, 2023 by flanagaj Link to comment Share on other sites More sharing options...
nod Posted September 14, 2023 Share Posted September 14, 2023 We are over 400 m2 total floor space including the garage and look set to complete within our 350k budget Link to comment Share on other sites More sharing options...
Dave Jones Posted September 14, 2023 Share Posted September 14, 2023 12 minutes ago, nod said: We are over 400 m2 total floor space including the garage and look set to complete within our 350k budget Be wary taking notice of this, this is not a standard build. It's like buying a car and not including the engine as you made it yourself. Normal costs are an absolute minimum of £2.5k m2 NOT including groundworks. Link to comment Share on other sites More sharing options...
nod Posted September 14, 2023 Share Posted September 14, 2023 (edited) 3 hours ago, Dave Jones said: Be wary taking notice of this, this is not a standard build. It's like buying a car and not including the engine as you made it yourself. Normal costs are an absolute minimum of £2.5k m2 NOT including groundworks. What’s not standard about it It’s as self build as your going to get How your build going Dave ? Post some figures up There a full spreadsheet of our previous build on her 815m2 Bit before your time on here 😁 Edited September 14, 2023 by nod Link to comment Share on other sites More sharing options...
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