Build cost factors
There are several key factors which affect the cost of building a house:
- Design complexity
- Build quality
- How many storeys
- Professional services required
- Other costs
As you would imagine, the size of the property you plan to build is a major factor in assessing the overall cost. Building costs range from a minimum of £1,750 per square metre to as much as £3,000 per square metre.
The cost of building a new house varies considerably in different parts of the UK. This is largely because of variations in the cost of land.
The price of land isn’t the only location-specific factor. Labour costs are lower in some parts of the country than others – partly due to differences in the cost of living.
The more complex the design, the higher the cost. It’s as simple as that. More complex designs take longer to build, add to the cost of materials and will have incurred higher fees from your architect in London.
The materials you choose and the finish you want will have a big impact on the pricing for your project. From roof tiles to gutters, lighting to stairs, every decision you make on the quality of the fittings and finish will affect the overall cost of your project.
How many storeys
The more storeys you have, the higher the price will be. A single storey residence may be cheaper to build than a three-storey townhouse, but for many people, the size, shape and location of the plot will dictate the number of storeys required to achieve the desired amount of space.
Professional fees for your architect, project manager and other consultants will usually add an extra 15% to the total construction project costs.
There are many potential complications which can arise during a build. Some may be identified at the planning stage, while others may not be known until work on the build is underway.
If access to the site is not straightforward, for example, because there is a narrow access track, you may incur additional costs. Some lower-cost options, such as for deliveries, equipment hire, etc. may not be available to you.
It can happen that a site is not known to be contaminated until work begins on preparing to lay the foundations. This is where your contingency budget comes into play.
Shop around and make sure the professionals and contractors you use have experience of working on similar projects to you and have evidence of successful outcomes.
Other costs to consider:
Provided you are buying land only, you will pay less stamp duty on a self-build property, as you pay duty only on the land cost, not on the future property value. However, it is still a sizeable amount and needs to be included in your projected costs.
Planning application fees may not be included in your architect’s quotation – so make sure you budget separately for these.
It is essential to employ a structural engineer to ensure that your build project will be safe. You can expect to pay anything from £350 to £2,000 [+ VAT] for a building survey from your structural engineer.
If your site already has a dwelling on it, you will need to allow for demolition costs. The costs will depend on the size of the building, ease of access, and the materials in the building, For example, if hazardous materials such as asbestos are present in the property you can expect to be charged additional fees for the safe disposal of these materials. Costs can start from around £5k for the demolition of a small bungalow, but could easily rise to £15k if there are hazardous materials involved.
If you plan to build on a challenging site, such as on land with a steep slope, you may require some levelling work before the build can begin.
Even though your project is not yet a home, you still need to insure it. Choose a specialist self-build insurance policy which will cover your materials and land during the build process. Unless you plan to do the entire build yourself, you need to have employer’s liability insurance so that you are covered in the event of a contractor accident on site. Your policy should also include public liability insurance for your protection in case of any injury to a member of the public or damage to neighbouring properties relating to your building project.
Unless you are so lucky as to have all of the money for the build set aside in savings, you will need to borrow money. Costs to allow for include loan arrangement fees and interest charges.
Different build options affecting pricing
If you have bricklaying and other trades skills and are happy to do the work yourself, you could slash a third or more off the cost of your build, particularly if you can source the materials direct from trade suppliers. This works really well if you can call on friends and family to help with specialist jobs which you don’t normally do yourself.
Part DIY with subcontractors
This approach is perfect if you can do some of the work and want to purchase materials yourself but prefer to employ tradespeople to do parts of the build for you.
Equally, if you have project management skills, you may choose to save money by liaising closely with your architect and taking on some of the management of the build.
With a turnkey solution, everything – or just about – is done for you. Your main responsibilities will be limited to signing off on client decisions and paying the bill. For this type of project, some companies will offer a fixed price solution, so you have no worries about spiralling costs. Naturally, this is the most expensive approach to getting your self-build home.
What are the typical build costs for a self-build project?
To give you an idea of what your project might cost, here are some price ranges:
- Cost for building a 2 bedroom house: From £185k to £280k
- Cost for building a 3 bedroom house: From £240k to £365k
- Cost for building a 4 bedroom house: From £295k to £440k
- Cost for building a 5 bedroom house From £320k to £480k
These costs are for typical builds and can fall outside these ranges if you choose an unusual design.
Costs to build an extension
Some house building costs are not applicable to an extension. For example, you won’t have stamp duty to pay and in most cases, there are no demolition costs. Some extensions are classified as “permitted development” so do not even require planning permission. This will be determined by factors such as the size and design of the build, as well as the area. Whilst a planning application fee of £172 may not be payable, there would still be a lower fee, currently £86, payable for permitted development. Your architect will advise you on what consents are required for your particular project.
There are also some issues which are specific to an extension, and it is important to factor these into your extension budget.
Costs specific to an extension
If you are building a second storey on an existing single-storey building, for example above an attached garage, you will need to have the footings of the original building tested to assess whether they are strong enough to take the weight of an extension.
A groundworks company will dig test holes to check the depth and quality of the footings and you will need your local building control department to sign off before you can proceed to the build stage.
If you live in a conservation area you will need to submit a Design and Access Statement as part of your planning application.
Guide to architect’s costs (excluding VAT) for an extension:
- Planning application: £1150+ [covers designs and advice]
Council application fee
- Conservation areas only: fee for Design and Access Statement
- £1300+ [covers designs and amendments, advice]
- Fees for submitting plans to building control
- £350+ [covers full measurement and photographic site survey]
Whether your project is for a new house or an extension, it is advisable to set aside a contingency fund to cover unexpected costs. This should be at least 10% and ideally 15% of your total budget. You may get lucky and not need it, but the majority of building projects will encounter some costs which could not have been foreseen, so it’s important to have the finance in place to cover these eventualities. Otherwise, you may find you have to make compromises which you are not happy about, or your build project can quickly grind to a halt.
For further guidance on preparing a budget for your self-build or extension project, contact an architect, and make your first step towards building your dream home.