Planning a Build Budget

Construction Cost

Renovating, remodelling or extending a property can be an expensive business. That’s not to say that you can’t get good value or that it can’t be a sound investment. But your budget should be carefully planned and monitored so as not to let it get out of control.

The first step is making sure your budget is realistic. If it’s not it will creep up from the start. And once it begins it can be difficult to stop. But how do you know what is a realistic budget for what you would like to achieve?

As a starting point, most consultants will use a square metre rate based on the overall size of the project as a crude estimate. Obviously this varies wildly for projects with a high specification quality, bespoke design or constraints such as difficult site access. Allowances for such uplift have to be made on a project by project basis but for a typical domestic project, here are the figures I would use:

Typical Construction Cost / sqm*

New Build / remodelling – £1500 – £2000

Redecoration / making good – £800 – £1200

These figures are based on readily available web data for a structure and shell finished to a reasonable quality ( When planning your budget, additional consideration should be given to:

  • enhanced cost items such as kitchens / bathrooms;
  • large format glazing / doors, larger spans of structural steel;
  • generally enhanced level of specification;
  • remedial works to existing buildings & structures;
  • specialist design fees;
  • inflation & VAT.

For more specialist cost advice clients should seek the advice of an RICS chartered quantity surveyor.

Professional Design Fees

On top of this you are likely to need to consider professional design fees. In some cases this may not apply. You may for instance design a project yourself. However for most people engaging a professional designer is likely to save them money and a lot of stress in the long run.

An architect or experienced draftsman is likely to use the construction budget as a guide to calculating their fee. You can therefore assume an approximate square metre rate for design fees. Typically these might be around 5% of the construction cost for new build and 7% of the construction cost for remodelling and refurbishment.

Other Professional Fees

For other services, such as those of a structural engineer, the fee will be more dependent on what it is they are actually designing. Ie. Foundation designs will have an approximate cost by the linear metre, lintel and beam designs will vary less from project to project. For this reason it’s difficult to provide general advice on these costs but a typical domestic project range might be around £2000 – £5000. On top of any obvious costs in the category I would suggest having a contingency of around 15%.

Project Costs

Finally there are one off project costs such as planning application fees, building control fees…etc. These change all the time so the best way to access these is via your local authority website. Or if you’re struggling to find them, pick up the phone and give them a ring. Planning and building control tend to be one of the more personable local authority departments! Similar to the above, if there are obvious one off project costs you should try and get a feel for what these will be.

Sound steep?

Don’t worry, lots of projects have to be seriously scrutinised before they are made to stack up financially, recognising this now will mean the you’re at least ahead of the game. The first port of call if you need to reduce cost is to reduce footprint. This is normally the most effective way to reign a project in without compromising on the quality of finish. And don’t forget that a more compact layout means cheaper bills and maintenance too!

If you’re struggling then perhaps approach a professional designer to scrutinise your design and see how they can help make it work or reduce your cost per square metre. This will cost a bit more in the short term but is likely to offer better value down the line.

Or if you have a builder who you know you can trust, be honest with them. Tell them what you have to spend and negotiate with them on what they feel they can deliver for the money.

This pricing structure is a starting point to help you work out roughly how much building you can afford. As you work through a project you may well benefit from the advice of an appropriate professional. I would welcome any comments in relation to this cost model as the more feedback I receive the more accurate I can make it for people in the future. If you have experience with a project which does or doesn’t align to it I would love to hear from you. You can find my details in the contact area of the site.

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