First costing of project, opinions required

[Spainy86]

Following on from my previous thread about whether or not to use online estimates and/or a QS, a fellow user suggested trying to start out by costing the project myself so that is what I have done by undertaking plenty of online research, reading guides on here and finding online estimates (not yet at the point of putting out for tenders so a lot is based on generic online guides) - this is what I have come up with (spreadsheet attached).Build cost spreadsheet.xlsx

 

For completeness, I plan to build a 4 bed detached cottage (approx. 9m x 9m externally) with detached single garage (approx. 4m x 5m externally). The construction method will be brick and block.

 

Obviously, the below is just to give me an indication, I appreciate that people cannot comment generally on groundworks because that is site specific but I would appreciate input on the other items that are perhaps more generic and whether any of them seem way too low or way too high, also anything glaringly obvious that has been missed completely. 

 

Some things (like heating system) are undecided but I am concerned because that my calculation brings me out at about £1,050 per square metre (excluding plot) which seems very low based on reading this forum and bearing in mind that whilst I plan to project manage, my actual hands on involvement will be limited to "helping out" and "digging in" rather than saving significant labour on particular skills.

 

Any input would be gratefully received.

[CC45]

If you want a good quality finish (not brilliant but good) and are happy to let others do it then I'd suggest £1k/m2 internal is too low. We will come in less than that but like a few others here we have done a hell of a lot of the work - prob in excess of 60 or 70%.  I think you will be a lot closer to £1.5k than £1k.  I'd certainly make sure you can afford the higher one rather than the lower.

[Spainy86]

4 minutes ago, CC45 said:

If you want a good quality finish (not brilliant but good) and are happy to let others do it then I'd suggest £1k/m2 internal is too low. We will come in less than that but like a few others here we have done a hell of a lot of the work - prob in excess of 60 or 70%.  I think you will be a lot closer to £1.5k than £1k.  I'd certainly make sure you can afford the higher one rather than the lower.

Thanks, I had £1,500 per sqm in my head which is why I think that my own costings must be either missing something or be very low in certain areas, that is the feedback I am looking for

[Ralph]

£1,500 per sqm seems a bit more realistic but quite a bit depends on location. 

 

We are going to wash out at about £1,600, that's with a Scotframe kit, £20k plus of windows a metal roof and me doing pretty much zero of the work, we've also had a lot of land clearing and a 100 meter of driveway.

 

A lot of the builders quotes I got were north of £2,000 per sqm

[ToughButterCup]

5 minutes ago, Ralph said:

£1,500 per sqm seems a bit more realistic but quite a bit depends on location. 

...

 

That about nails it.

Ralph's point about location is critical. SPONS ( the architrects price guide) gives a national level guide using factors. With Outer London as 1 (one) it gives various factors for the regions. The factor  SPONS gives for Lancaster is 0.96 - but Sandbanks in Dorset will be significantly different (2.5?). Locally (15 miles away), there's a millionaire's row. Tradesmen talk about silly prices being the norm there.... (you can see it from the West Coast Main Line).

 

I'll be glad to come in at £1600 on 146 sq meters. The Devil is always in the detail.  

There seems to be a good deal of antipathy to SPONS on this board : costs £150. And has saved me many many times that price. Its hard work to get into, but a couple of days working at it repays the effort.

[Adrian Walker]

Just had a quick look at your build cost spreadsheet and the House Build of £54K is a bit light as is the garage at £10,800(IMHO)

Groundworks and retaining walls can often be tricky and hence costly.  You have made a good start at costing.

[AliG]

I think that £250 a square metre for the building is way too low. Have you calculated it just on the external wall area? Stone facing can be very expensive. What about the ceilings and joists and internal walls. I have a quote from MBC for a timber frame and that is about £400 per sq metre of house without the external walls. Admittedly you could be a lot cheaper if you reduce the insulation.

 

Lots of small things soon build up.

 

For example we were £60 a fitting for switches and lights. So imagine 10 downlighters in the kitchen, plus 6 sockets, plus 6 appliances. That is £1300 already, you'd be surprised how many electrical connections you need for heating, alarm, to the garage, etc. So you could double the electrics.

 

Including wardrobes etc you will probably have at least 15 doors, each door is approaching £300 by the time you include the door, the ironmongery, the frame and the fitting. So you are probably a few thousand short on the woodwork. You also have to think of things like wardrobe shelves, window sills etc.

 

You are short on the bathroom and flooring it you are planning to use tiled finishes etc.

 

Landscaping can be very expensive, a driveway plus patios etc could all come out at £50 a square metre.

 

Aluminium framed windows including bi-folds will be around 400 a square metre. You are probably looking at 50-100% more for the windows.

 

[Spainy86]

53 minutes ago, Adrian Walker said:

Just had a quick look at your build cost spreadsheet and the House Build of £54K is a bit light as is the garage at £10,800(IMHO)

Groundworks and retaining walls can often be tricky and hence costly.  You have made a good start at costing.

That's really good to hear that it is at least a decent starting point

 

In terms of the actual building, where do you think it is light? I took the figure of £250sqm for the highest range here https://www.self-build.co.uk/cost-guide-walls-and-insulation/ which is supposed to include builder’s profit margin, labour, materials, finishes, insulation and internal plastering but does not include windows and doors. The groundwork has been included elsewhere on the spreadsheet but obviously, that figure is the biggest unknown at the moment. Windows and doors have also been accounted for elsewhere.

 

It would be useful to hear peoples thoughts on what the build sqm £ should be if £250 is on the low side?

 

Also, any feedback for any other elements that seem too low would also be gratefully received. I have not picked the £1,050, that is just what it has come out at based on all the estimates that I have put in the for various aspects so if that figure is low, I must have either missed some aspects of the build or underpriced them. Also, I have got the price per sqm build cost from the total external dimensions on the build. If that isn't correct and it should be taken from the internal measurements, that will obviously bump up the cost per sqm build cost.

[nod]

You will save a lot of money not using a kit house 

Just as I started our build I plastered and rendered two identical houses one was kit with a block and stone outer skin 

The other was block and block also with a stone front 

Out of curiosity I asked where each where upto to water tight 

One was 62k the other just over a 100 k 

 

We have come in at £830 km2 for traditional doing the majority ourselves and could have easily shaved Off 150m2 for a basic build 

B&Q kitchen Bathrooms Laminate floors Gravel drive etc 

 

You also need to keep professional fees down to a minimum 

Bats Newts contaminated land Soil surveys Can all rack up 

If your not careful 

[Spainy86]

4 minutes ago, AliG said:

I think that £250 a square metre for the building is way too low. Have you calculated it just on the external wall area? Stone facing can be very expensive. What about the ceilings and joists and internal walls. I have a quote from MBC for a timber frame and that is about £400 per sq metre of house without the external walls. Admittedly you could be a lot cheaper if you reduce the insulation.

 

Lots of small things soon build up.

 

For example we were £60 a fitting for switches and lights. So imagine 10 downlighters in the kitchen, plus 6 sockets, plus 6 appliances. That is £1300 already, you'd be surprised how many electrical connections you need for heating, alarm, to the garage, etc. So you could double the electrics.

 

Including wardrobes etc you will probably have at least 15 doors, each door is approaching £300 by the time you include the door, the ironmongery, the frame and the fitting. So you are probably a few thousand short on the woodwork. You also have to think of things like wardrobe shelves, window sills etc.

 

You are short on the bathroom and flooring it you are planning to use tiled finishes etc.

 

Landscaping can be very expensive, a driveway plus patios etc could all come out at £50 a square metre.

 

Aluminium framed windows including bi-folds will be around 400 a square metre. You are probably looking at 50-100% more for the windows.

 

That is exactly the type of feedback I was after, thanks

 

My building cost calculation is solely based on external wall area so I don't have ceilings, joists and internal walls costed, well spotted

 

Is the £400 per sq metre of house something to be added onto the build cost then to account for ceilings, joists and internal walls (subject to insulation)?

[AliG]

MBC are expensive and timber frame is expensive compared to block work, but that figure does include the internal walls, first floor and roof joists. I had a look at that cost estimator and it is a bit odd that it says it includes internal plastering but it doesn't mention joists, ceilings and internal walls.

 

What you can find is that you have thousands of pounds of small items that you never thought of. You could be a few hundred pound for the mastic man for example. Then there is burglar alarm, scaffolding(not sure if that is in the wall cost estimator), light fittings, door thresholds, extractor fans, temporary stairs, bathroom mirrors, tv/ethernet/wifi. The list goes on.

 

I do think you could also double the professional fees. Some people are being quoted thousands for just soil investigations. You will need plans, warrant drawings, structural engineer etc which could easily double that figure.

 

Net net the £1500 figure is probably a decent rule of thumb. Plus or minus on that will depend a lot on the finishes and the amount of insulation. A set of oak and glass stairs could be 4x the price of a set of softwood painted stairs. Fully tiling a bathroom will cost £1000-1500 versus a splashback that might cost a few pounds.

 

The amount of land you have around the house and need to landscape will make a big difference. Hard landscaping and retaining walls are very expensive compared to grass.

 

[Ralph]

18 minutes ago, nod said:

You will save a lot of money not using a kit house 

Just as I started our build I plastered and rendered two identical houses one was kit with a block and stone outer skin 

The other was block and block also with a stone front 

Out of curiosity I asked where each where upto to water tight 

One was 62k the other just over a 100 k 

As with a lot of things about building what is true for one house is not necessity true for another. We had three or four builders insist they could build the house cheaper by stick building the frame themselves. When we got final costs in they were pretty much the same but for less quality in terms of u values and air tightness. 

[nod]

14 minutes ago, Ralph said:

As with a lot of things about building what is true for one house is not necessity true for another. We had three or four builders insist they could build the house cheaper by stick building the frame themselves. When we got final costs in they were pretty much the same but for less quality in terms of u values and air tightness. 

I’ve worked on both for over thirty five years and chose to use traditional Airtightness isn’t an issue with traditional 
Most self builds are TF because it’s quicker and more convenient 

But TF kits are over priced 

Some of the TF  houses I’ve worked on have a bare minimum of fire protection and are thrown together 

TF houses have a very short lifespan compared to tradition 

Sure there are TF houses that are hundreds of years old 

But they are not made of unseasoned ;4x2 and OSB 

They just don’t look good value for money 

 

I’ve built a 5 bed 3 bathroom home 

for under 200 k valued at 750k 

I know if I would have gone the TF route it would have cost far more 

[LA3222]

1 hour ago, nod said:

TF houses have a very short lifespan compared to tradition 

It may just be me but I don't agree with this comment at all. I know that when you google you will see figures of 60yrs etc lifespan for a timber frame but lets be honest here, if they were only going to last for 60yrs then:

1. Who the hell would want to build with it.

2. Why would you build with it.

3. How the hell are you going to mortgage it.

 

I just don't buy it, I expect they will last a far greater time than that quoted - provided that they are constructed correctly.

[CC45]

ground works and timber frame errected cost us £250/m2.  I did look at stick build - would have saved ~ £40/m2 but you need the right crew to make it and not too many with experience around us.

 

Next time will be block & block with wide cavity for insulation.

[Ralph]

44 minutes ago, LA3222 said:

I just don't buy it, I expect they will last a far greater time than that quoted - provided that they are constructed correctly.

I hope so because we are screwed in Scotland if not, 80%plus of the market is TF and our weather is not exactly kind.

[LA3222]

23 minutes ago, Ralph said:

I hope so because we are screwed in Scotland if not, 80%plus of the market is TF and our weather is not exactly kind.

I'm just building my SIP house now, if it only lasts 60 yrs then there is a real danger of it falling down whilst I am still living in it?

[Mr Punter]

1 hour ago, CC45 said:

Next time will be block & block with wide cavity for insulation.

 

@tonyshouse would approve!

[Andrew]

I've just spent £5k on fascias and soffits, fitted. Budget was £3k including the gutters. Went for plastic as don't want the maintenance but was amazed how quickly the cost of the materials added up. 

 

Valley boards and noggins - had no idea what these were two weeks ago. Turns out the roofer doesn't do them and they weren't included in the timber frame package. Fortunately the lads on site did it for beer money but it's all these little things that add up really really quickly.  

[Thedreamer]

5 hours ago, nod said:

I’ve worked on both for over thirty five years and chose to use traditional Airtightness isn’t an issue with traditional 
Most self builds are TF because it’s quicker and more convenient 

But TF kits are over priced 

Some of the TF  houses I’ve worked on have a bare minimum of fire protection and are thrown together 

TF houses have a very short lifespan compared to tradition 

Sure there are TF houses that are hundreds of years old 

But they are not made of unseasoned ;4x2 and OSB 

They just don’t look good value for money 

 

I’ve built a 5 bed 3 bathroom home 

for under 200 k valued at 750k 

I know if I would have gone the TF route it would have cost far more 

 

Round our area plenty of houses of more 'traditional materials' have there own problems.

 

The one point I would make on double block houses, what are the blocks made of? I've seen block where the light weight blocks chip/crumble very easily. If the house is double block out of traditional heavy blocks I would agree with you. Up to the 90's in Skye, houses were double heavy block but now 95% houses are timber frame. I actually mentioned this when considering and loads of people said it would be very odd to build out of double block in my area. 

 

Our home was stick built but as more house are built this way here then the joiners have more experience.

 

[tonyshouse]

I used medium density recycled aggregate blocks, hate aircrete, too many cracks  

[nod]

1 hour ago, Thedreamer said:

 

Round our area plenty of houses of more 'traditional materials' have there own problems.

 

The one point I would make on double block houses, what are the blocks made of? I've seen block where the light weight blocks chip/crumble very easily. If the house is double block out of traditional heavy blocks I would agree with you. Up to the 90's in Skye, houses were double heavy block but now 95% houses are timber frame. I actually mentioned this when considering and loads of people said it would be very odd to build out of double block in my area. 

 

Our home was stick built but as more house are built this way here then the joiners have more experience.

 

It just doesn’t fill me with confidence when it’s stated within the industry a soft wood TB is expected to last 25 30 years 

 

If I was to have TF house I would fire stop between flour ALL electrical fittings would be with there own one hour fire rated box 

We do this on apartments and commercial premises 

It takes us about ten minutes per box to make and fix 

TF are great for speed 

We’ve recently done a site in Preston Can’t remember the TF company All Scottish lads 

Nothing was square Everything went in at a rate of nots 

 

But I can see the attraction for self build 

Your looking around £20 m2 for tradition plus materials 

You won’t get near that with a timber frame company 

 

[dpmiller]

@nod  £20 m2 for *what* precisely?