Huge variation in architects' estimates of potential build cost?

[Dunc]

So we're talking to a few designers (Architects & Technicians) for our self build in Scotland (likely ~150m², 1.5 storey, longhouse style, likely timber frame).

I am not too surprised to find that architectural fees vary a fair bit from one Technician who will do just a single initial design then refine, to one PH Architect who proposes multiple sketeches and using virtual reality during the process...probably 15K difference in total project fees.

 

BUT these designers are suggesting a huge range in their expectation of cost-to-build:

One (non-passive certified) suggested a main contractor build would be in the region £2000/m² for "better than building regs" heading to £2500/m² working to "passive levels".

A certified passive Architect reckoned minimum £3000-3500/m² for a main contractor passive build (likely including ASHP/UFH).

Another passive certified practice, specializing in self builders, was "very comfortable" to think that £1500-1800/m² for a fully "functional passive house" (e.g. aiming for no need for ASHP/UFH, rather just using 3kW heater on the MVHR) would be perfectly do-able on a self-managed build and up to £2000-2500/m² tops for a main contractor.

 

I'm at a complete loss who to trust and what to do to interrogate these numbers in more detail. £3500/m² is out of budget...obviously one could be tempted towards someone indicating lower likely build costs (even though their fees are higher) but getting caught out half way through would be disasterous. Prior to any kind of design it's not even possible to splash money on a QS...any suggestions please?

 

[Conor]

All of the numbers are "correct"... all depends on your spec of finish. I'd be budgeting £2k/m2 for a basic/modest finish with simplified heating system.

[Bozza]

https://www.dan-wood.co.uk/en/projects/point-158a-e
 

If this company can build this (longhouse ish simple shape and 164sqm) as a turnkey, allowing for founds, kitchen etc etc this house would cost you around £300k to build, so £1800 ish per sqm.  Thats a turnkey imported house.

 

So you can spend less than that if you sub contract etc.  More than that if you put in higher end products & spec. A kitchen can cost £6k to £60k for example.

 

I was just away to say therefore allow £2k per m2.  That would be reasonable.  As I was typing this @Conor just posted exactly the same estimation.  And I was just away to also say all the estimates are correct.  It’s like saying how much to buy a new car.  The answer is anything from £13k to £millions.

 

if £2k-£2.5k per sqm is your build budget, you’ll be ok for a “normal” self build.

 

 

 

 

 

[saveasteading]

49 minutes ago, Dunc said:

using virtual reality during the process...probably 15K

What they say.

It is also possible that the architects have varying knowledge or skills in cost levels.

You could ask for references for similar projects they have gone.

 

Virtual reality, as they are calling it, does not necessarily cost much more.

If they design from the outset using a 3D suite, then any view is available, and then gets used for detailed construction drawings.

 

But a few sketches for planning  (with another go at detail later will) cost much less than  detailed 3D design from the outset..but not that much difference.

[Seren161]

@Bozza and @Conor are right. My experience was that 2 different professional cost estimating/project management companies quoted between £2100/sqm and £2800/sqm for our relatively mid range project…This was 12 mths before the build started so factor in the material increases and looked more like £2200-£2959/sqm. 

Real cost : planning, prelim investigations, random special requirements, improved spec , unexpected expenses and completed build..less than 1800. ..and the professional cost estimating service was the most inaccurate.

An expectation of 2-£2.5k/sqm is realistic and with some careful planning you can probably come is slightly lower.