How to estimate self-build costs before starting

[selfbuilder91]

I am looking into the idea of doing a self-build and trying to get an idea of the costs involved before actually committing to it (e.g. by buying land or paying architect fees). I would like to know if the whole thing is at all feasible before investing a bunch of money in it. I have seen all the usual £/m² estimates, but these seem to vary quite a bit and don't always include all of the associated costs (e.g. architect/SE fees, applications, warranties/insurances etc.), so I'm wondering if there's a way to get a more accurate idea of costs at this stage of the journey, or is this just what people go on to start with and only get more accurate estimates as the build progresses, e.g. after land is purchased and designs are drawn up by an architect etc.? I have seen cost estimating services such as estimators.com mentioned in this forum, but it seems that these require designs which I presume would only be done much further into the project and after already having invested quite a lot of money.

 

Any tips for how I should go about initial budgeting/estimating would be greatly appreciated 🙏

[Redoctober]

Hello and welcome - you find yourself in a very familar position to many on this forum. Most have been in this position, me included, whereby the uncertainties can be overwhelming. 

Sadly the stark truth of the matter is no one really  knows!  

So in order to try and understand whether a project is vaiable and affordable, one has to research, read, enquire and eventually " gamble".

Obviously the more research one does, the less of a gamble it becomes - hopefully, you may get to a position whereby is it becomes an almost cert - !!

We started our project 5 years ago and a lot of what you mention, we encountered. Like you we had no idea but a limited budget! 

Have a read of my blog, it may help albeit the figures are 5 years out of date.

One thing is for sure though. You will have to start spending some money, in order to progress your decision making, so good luck with it - 

 

 

[saveasteading]

As above. Nothing is certain. This is not a factory producing identical product in controlled conditions.

 

If you know exactly what you want, where you want it snd everything about the site, then there could be some degree of certainty. Do you?

Even so, 4 or 5 fair and expert contractors using all their skills to cost the job, their family's wellbeing depending on it, as it does,  could easily vary 30%.

 

Then allow for fees between zero and 30%. And then allow for the unknowns...weather, inflation etc.

 

 

In summary an industry expert will have some degree of certainty. Anyone else is taking a big risk.

 

[Dunc]

We've just been through this and are now in the process of purchasing a plot and working with an architect towards a planning applicaiton so I can share a little recent experience, but the short version for me is there are too many variables to get an accurate cost.

Some thoughts:

£/m2 ususally doesn't generally include cost of plot, professional fees (solicitor, architect, engineer, other specialists), getting utilities installed, or lanscaping the garden afterwards.

Ground work/foundation seems to be the biggest unknown - untill you dig a hole you don't really know what's giong to happen, although if your architect is local and has done other work in the area they may have a general idea of what's likely to be in the ground.

Architects may be able to give you an early estimate, just based on your general requirements, location and their ethos. However I had a range from £1800 to £3500. The architect (actually an architectural technologist) we've gone with reckons £2000-£2500/m2 for a timberframe build in the Highlands.

We had a quote from one local timberframe company with their in-house architect for a turnkey build (this is before having any desing, jsut a bullet list of "wants" and an idea of size to form an architectural brief). That was guide-priced at £3500/m2. I found this really hepful as the spec included things like oak internal doors and skirting, a Mitsubishi Ecodan ASHP, Paul MVHR, 4kW PV and Tesla Powewall. i.e. there was enough info to see it was a high spec finish. So I see this as a ceiling price to beat and a worst case scenario.

If timberframe is of interest, have a look at the catalogs of some stock stuff e.g. scotframe, hebhomes, dan wood who will give you prices to get a ball park for the main structure [but keep in mind there's probably the same cost again in turning a shell into a useable house]. I don't know if there are similar offerings for other build methods?

Architect & engineer fees vary quite a bit and the more expensive architects we had quotes from were in the 10-15% of build budget range (even though they quoted a fixed fee). Allan Corfield architects have a pretty good resource on their website and do provide ballpark costs which were pretty close to their quote for us.https://acarchitects.biz/self-build-architect-cost/ and  https://acarchitects.biz/professional-fees-self-build-project/

 

As above, there seems to be a certain level of commitment required just to get an idea of what it'll cost and it seems one has to start investing some cash to even find out if it's going to be possible. It feels like a big leap of a cliff wondering if the parachute will open!

[ToughButterCup]

1 hour ago, selfbuilder91 said:

...

so I'm wondering if there's a way to get a more accurate idea of costs at this stage of the journey,

...

 

No, there isn't.  The availability of money is only one factor in the total cost of any build.

But there are 'givens'.

• The cost of land in your chosen area
• The cost of money
• Your nett income(s)
• Your risk appetite
• Your life experience
• Your network of relevant contacts
• Your determination - resilience
• Your support networks
• Your dream

Look hard at all of those.

Read all the OhShitStories on this site. You WILL have at least two.  And then review the above list.

[JohnMo]

Other variables are

How many bells and whistles you want

Such as, home automation, flash lighting schemes, etc etc. Single storey or multi storey have different cost profiles. Your ASHP can cost upwards of £15k plus your heating system, so about £25k, or you can do it yourself for £4-5k for ASHP and full UFH.

 

How much work you are doing or willing to do yourself or paying others to do. Are you project managing or going to someone for a turnkey house, or actually building yourself.

 

Can you design the internal space or do you need someone to do it for you?

 

How difficult is site is to work with, you may have huge amounts of material to get rid of, and it huge amounts of landscaping to do once you have built the house. Or neither on a small site.

 

 

[nod]

Your probably looking at £2000 ish per m2 depending on what you want to do yourselves Timber frame will come at a premium compared to a solid build But TF is without question more convenient for a self builder 

Normally on here most include the cost of Architects and services in the m2 cost Never the plot price 

[eandg]

Do plenty of research and consider your cashflow too - we ruled out using an architect early on as most of their fees would be incurred pre-build commencing, which for us would have killed our cashflow and meant we couldn't progress through the stages to draw down our mortgage (i.e. if we spend £20k on architects fees we'd not have been able to install the windows and doors to get us to weathertight and get the next lot of cash). 

 

We've worked pretty hard to cut fat from the budget and did a bit ourselves and will be about £1450/m2 all in with higher than normal groundworks costs. Architectural technician doing our drawings. If you're going the timber kit route you'll find some of the companies will have their own in-house design teams that can take off your own sketches/floorplans to get you through building regs. 

[Dave Jones]

fees are miniscule, less than 10%, of the price of the plot+build costs.

 

If these are your main worry then it may be a case of wood for the trees.

[selfbuilder91]

Thanks all. Sounds like it's a case of having to use the £/m² estimates at this stage and then hoping for the best 🤞

 

On 25/06/2023 at 15:20, saveasteading said:

If you know exactly what you want, where you want it snd everything about the site, then there could be some degree of certainty. Do you?

 

Don't know this yet. Currently just have a rough idea of what I'd like and roughly where I'd like it. However, I'll likely only be in a position to be able to start building in a few years' time, so plenty of time to work these things out. Just trying to get a head-start on whatever budgeting/planning I can for now.

 

On 25/06/2023 at 15:21, Dunc said:

Architects may be able to give you an early estimate, just based on your general requirements, location and their ethos.

Did/would you speak to architects about early estimates before commissioning them and/or before purchasing land? Are they inclined to give this sort of information to prospective clients?

 

 

On 25/06/2023 at 15:21, Dunc said:

If timberframe is of interest, have a look at the catalogs of some stock stuff e.g. scotframe, hebhomes, dan wood who will give you prices to get a ball park for the main structure [but keep in mind there's probably the same cost again in turning a shell into a useable house]

I've looked a bit at Danwood, and while I probably won't be going for a turnkey service, it did seem useful to be able to see what sort of thing you can get for what sort of price. I think their price includes everything except kitchen and foundations - I wouldn't have thought that would double the cost though 😬

 

On 25/06/2023 at 17:12, nod said:

Your probably looking at £2000 ish per m2 depending on what you want to do yourselves Timber frame will come at a premium compared to a solid build But TF is without question more convenient for a self builder 

Normally on here most include the cost of Architects and services in the m2 cost Never the plot price 

£2000/m² including architect's fees sounds pretty good, although I'm guessing I would be at the higher end of the £/m² estimate range as I'd be going for a relatively high spec and probably in the South-East of England.

[Dunc]

1 minute ago, selfbuilder91 said:

Did/would you speak to architects about early estimates before commissioning them and/or before purchasing land? Are they inclined to give this sort of information to prospective clients?

£2000/m² including architect's fees sounds pretty good

Yes, we interviewed 4 architects/designers in detial in order to select one to work with. That inculded giving them a brief, having a 1hr call with them and asking for their fees and their expectations of build costs. We did this in paralell with looking for a plot.

None of the architects we spoke with included professional fees (architect, engineer, solicitor) or utilities provision in the cost/m2 estimates....so, as pretty much everyone else has said: it's a guessing game!

 

[markc]

The plot itself can have a massive impact on costs, access for deliveries, ground conditions, distance and availability of services all affect your build cost

[saveasteading]

2 minutes ago, selfbuilder91 said:

relatively high spec and probably in the South-East of England.

So you do know what you want and where.

 

Land is stupidly expensive . Say £15M an acre.*

Labour likewise. 

Anything special, ie not a kit or a standard design will increase the cost too.

 

For these reasons, we and our family have done 5 renovations but no new-builds in the SE.

 

* there is what we yokels call "London money". Ie if someone from the big smoke wants it, then they will have it, apparently regardless of cost and sense.

Nice view, near a station, no near neighbours will also increase the land cost dramatically.

 

In reverse logic....what will your finished project be worth to sell? Add 200k to that to get an idea of budget required.

 

 

[ToughButterCup]

19 minutes ago, selfbuilder91 said:

...
Did/would you speak to architects about early estimates before commissioning them and/or before purchasing land? Are they inclined to give this sort of information to prospective clients?

...

 

Here's how our architect answers that question .....

 

https://rocketarchitects.co.uk/pricing

 

Edited June 27, 2023 by ToughButterCup

[saveasteading]

2 minutes ago, Dunc said:

it's a guessing game!

 

It's not guessing.

Some people are good at it. If you are not, then you need people  who are, and have to pay them.

 

Handy hints on here are a good start. Hence with deep reading n here you might find a concensus at allowing £3,000/m2.

More for the South East. More for flash.

 

There is always some risk. But that is not the same  as guessing.

[saveasteading]

2 minutes ago, ToughButterCup said:

how our architect answers that

Without any reference to construction cost.

[Dave Jones]

Why bother with architects to do the build ? Much better off employing someone who knows how to build like a project manager / QS/ Builder. 

 

Get a detailed construction drawing pack from them, which will be full off errors like odd window/door sizes that don't work brick and add cost, then get it QS'd so you know ballpark what its going to cost.

 

Depending on how hands off (costing you ££££££) you want to be tender and engage a builder, paid in arrears to a written contract. Pay a quantity surveyor to visit each month to determine what the builder is going to be paid against the contract QS schedule.  The fees you save doing this method instead of buying the architect another BMW will sort at least a bathroom.

 

This is the process the banks use for developers and it works. It protects the bank.

 

This way the builder knows they cant leg you over and leaves you to organise the big ticket items, windows, kitchen, second fix items.

 

3 bits of paperwork you must have: Construction Drawings from Architect. Fully qs'd costings derived from these drawings and a contract for the builder to sign.

 

find a good QS who will visit site to prepare you a monthly report so you will be told to the penny how much to pay the builder. 

 

For quality and monitoring a project manager could be worth employing, depends how good your builder is really.

 

 

 

 

 

[ToughButterCup]

3 hours ago, saveasteading said:

Without any reference to construction cost.

 

He's up-front about as far as I remember.....  Thats one reason we chose him.

 

Quote

Pricing Letter - 

After you get in touch with us, we will happily come and see you to discuss the project for free, we'll then write to you to confirm what we'll do and what we'll charge- so you're entirely sure of what you'll get and what you'll pay.

 

Other Costs - 

To design your project there will be some other costs you will have to pay. These are for things like application fees (e.g. Planning and Building Regulations) and consultants (e.g. Structural Engineers'). We'll advise who may need to be involved and what this may cost at the outset (usually in our Pricing letter to you).

 

We'll then get quotes from the best local consultants, for you to choose from, as the design progresses.

 

https://rocketarchitects.co.uk/pricing

 

[saveasteading]

2 minutes ago, ToughButterCup said:

discuss the project for free.

Essential. Being happy with a potential client is essential.

[Alan Ambrose]

>>> In reverse logic....what will your finished project be worth to sell? Add 200k to that to get an idea of budget required.

 

Hilarious, but true often I suspect.

 

>>>

Get a detailed construction drawing pack from them, which will be full off errors like odd window/door sizes that don't work brick and add cost, then get it QS'd so you know ballpark what its going to cost.

 

Depending on how hands off (costing you ££££££) you want to be tender and engage a builder, paid in arrears to a written contract. Pay a quantity surveyor to visit each month to determine what the builder is going to be paid against the contract QS schedule.  The fees you save doing this method instead of buying the architect another BMW will sort at least a bathroom.

<<<

 

Nice, super-valuable advice I believe. thanks.

[JohnMo]

And there is another place they go for typical build pricing, which is way off, its good for planning stage, as it keeps council planning application cost down, but miles off for actual house building costs.

[HughF]

My architect says that RICS are suggesting £3000+/m2 at the moment.

 

No idea what we'll end up at with our rear extension, I've got the builders on time+materials at a reasonable day rate.

[Seren161]

Our two most wildly inaccurate quotes came from a professional cost estimator and a professional builder…Yet another project manager eyeballed the finished project and estimated our costs surprisingly accurately after a brief tour of the property. My point is there can still be significant differences regardless..We had multiple costings from many sources some paid for and some free “ calculators” and this informed our feasibility assessment.

We went with a main contractor.  3 months post completion with all the costs calculated.. we ended up circa £1850/sqm for build costs including professional fees, investigations, planning, landscaping, light fittings, solar, ASHP, 3d renders etc..

Main exclusion to this figure: Land costs as we were a demolish and rebuild project. We are south east based but not in one of the more affluent parts of east kent.. All the variables matter.. Design, Build method, Spec, Main contractor or actual self build, Project manage yourself or not, Slope of plot and location…Serviced plot or no..So no easy answer..I found using as many costing and estimating resources as I could ( most of them free including this forum and most of them allowing me to change the variables a few times) as well as the TF companies even though we eventually went with Masonry gave us a good indication of financial feasibility. 

Edited July 6, 2023 by Seren161

[saveasteading]

A nice summary. Can you save this for future re-use? So many initial posts are, " what will it cost", as if it was a fridge from  a shop.

 

May I suggest though that the inaccurate costings were perhaps accurate as to what that builder would have cost.

I'm guessing the estimator quoted high.....they daren't be low.

 

And of course perhaps you are the reason for the successful outcome. Good manager, firm but fair, and not changing your mind regularly? And you are not costed in to the final figure.

Edited July 6, 2023 by saveasteading