A detailed budget plan will help you to assess the overall financial feasibility of your project. This enables you to compare total costs with your home’s end value — something many lenders, especially the banks, will want to see before they will release any funds.
There are many factors that determine the cost of building your own home, from how much work you do yourself, to the level of professional involvement from an architect or project manager; from the shape, size and height of your design, to the quality of the fixtures and fittings you choose. Even the region you live in affects build costs because labour prices vary across the UK.
This guide will equip you with an understanding of all of the factors, enabling you to plan your self build project and weigh up your options to get the very best out of your available budget.
How Does Build Quality Affect My Costs?
The quality of the specification affects only certain aspects of the total budget.
Costs are calculated for three levels of build quality — standard, good and excellent. Standard is the minimum level of specification typical of most new build developments, good is the level of the average self build home and excellent – whilst by no means an upper limit – is typical of a top-end build. Quality has the largest effect on the cost of fittings and finishes – most notably the kitchen – and external materials but not on the ‘nuts and bolts’ such as foundations.
Please note, figures quoted are based on an average from our build costs tables and will vary according to region.
Where Does the Money Go?
This is the breakdown of a build budget for the average house.
Seeing where the money goes in your build helps to put certain decisions into context. For example, the relatively significant proportion of typical expenditure that goes on sanitary fittings sits uneasily against less than half of it spent on a typical heating system. The entire cost of the exterior, including chimneys, external doors and windows, represents only 50% of the total costs with the balance going on internal trades, fixtures and finishes. Figures include labour and material prices.
So What Will My Building Project Cost?
Here’s how to assess your future costs and understand how they are affected.
The H&R Average Build Cost Guide shows the average cost per square metre for building new one-off houses across the UK. These average figures are calculated from real project costs recorded by the Royal Institute of Chartered Surveyors’ Building Cost Information Service, and are based on gross internal floor area (the inside of the external walls).
Figures are shown for three different levels of quality, from standard to excellent, and for three sizes of house, to allow for the economies of scale achieved on larger projects. By adjusting these average figures to suit the characteristics of your individual project, you will get a good indication of how much it will cost to build your home in today’s market.
First you will need to work out the total internal floor area of your proposed plans using a scale ruler (or ask your designer to work this out for you). To work out the build cost you need to find the relevant cost per square metre for your project from the table, and multiply this by your total floor area. Finally you need to adjust the total by following the notes on these pages.
What Can I Afford to Build?
If you don’t have any plans yet, but just want to work out how large a house you could afford to build, start by getting an idea of your total available budget. Talk to self build lenders (you can find these in the Homebuilding Sourcebook) and find out how much you could borrow, then add to this any savings you have and any equity you can release by remortgaging or selling your current home.
Next visit plotfinder.net to get an idea of typical plot prices in your area. Take away the cost of a plot from your total budget, allowing for legal fees and Stamp Duty (1% on plots over £150k, 3% on plots over £250k and 4% over £500k) and a £6,000 allowance for connecting to services such as electricity and water. The remaining balance is roughly how much you will have to build the house, including design fees and any fees for project management.
You can use this figure to work out how large a house you can afford by dividing it by the average build cost per internal square metre for your area and your chosen level of build quality.
Total budget − cost of plot = build budget
Build budget ÷ average build cost/m²* = internal floor area (in m²)
* average for your area and chosen build quality
How Your Own Level of Involvement Affects Costs Project Management
The Build Cost Table shows costs for four different build routes, ranging from using a main contractor, to running the build yourself, co-ordinating the different trades, supplying materials, plant, scaffold, and statutory inspections as required. As a general rule, the more you take on yourself, the lower your costs will be. Managing the build and doing some of the work yourself can reduce average costs by 15% depending on how efficiently you manage the build.
If you decide to substitute some or all of the labour costs with your own labour (you can undertake every aspect of the building work with the exception of connecting gas appliances for which you must use a CORGI-registered contractor) you can reduce the average build costs very substantially. Approximately 50-60% of the total build cost is labour, so if you do all of the work you are allowed to you could reduce the costs further than the table suggests.
In practice most DIY self builders leave the groundworks, brickwork, plastering, first fix carpentry, plumbing and electrics to the professionals and take on the internal second fix trades such as laying floors, fitting kitchens and bathrooms, hanging doors, fitting skirting and architraves, boxing-in, decorating, tiling, landscaping, and connecting sockets and light fittings.
The build cost figures do not include design fees, planning fees (currently £385 for a new dwelling) engineer’s fees or Building Regulations fees. Make sure you have allowed for this in your budget, together with any fees for finance or insurance.
On larger projects a professional such as an architect, surveyor or engineer is usually retained to put the project out to tender, appoint the builder, and administer the contract through to completion. If this is the case you will need to add an allowance for fees at 5-10% of the total contract value (construction cost).
How Size Impacts on Cost
As the size of your intended home grows, the fixed costs tend to become less important to the overall budget.
A general rule is that, if other factors are kept constant, costs per square metre decrease as the house design increases in size, indicating that there are economies of scale in housebuilding. This is largely because the cost of building more volume does not require a proportional increase in labour and materials, and generally requires the same number of doors, sockets and switches, etc. The rate of decrease slows, however, as the building gets larger and starts to require nonstandard structural elements for extra-wide floorplans and openings.
Some Things To Consider
Building on a sloping site will increase your build costs because of the work involved. As a general rule, each 5° of slope from level on the site will increase your build costs by £5,000 (Brinkley’s Slope Law proposed by Mark Brinkley, author and H&R Contributing Editor).
Plan, Shape and Layout
The vertical elements such as walls, windows, doors and wall finishes are affected not only by the area of the building but also by its shape. A square building, for example, is more economical in its use of external walls than an oblong building of the same area. The cost/m² of gross floor area for external walling elements decreases as the wall/floor ratio decreases.
Using the roof space to create an additional attic storey is a popular way to add more living space. There are some additional costs involved: staircase, attic trusses or a traditional cut roof, increased roof pitch, and, in the case of a three storey dwelling, the addition of fire doors to create an enclosed 30-minute fire-resistant stairwell as an escape route. Using the existing volume in the roof is still cost-effective, at around 70% of the average cost/m² of the ground or first floors.
How Design and Build Affects Cost
The different choices you make about the materials and construction methods you use will have implications on the cost of your project. It therefore helps to understand how to make adjustments to your specification to fit your budget.
The external walls of your home represent on average 15% of the total construction cost. Most self-build homes are built using insulated cavity walls with an inner structural leaf of concrete blocks faced with brick, stone, hung tiles, timber or another concrete block and render. Building with standard facing bricks on 100mm concrete blockwork, with a facing brick costing £325/1,000 and 50mm partial-fill cavity insulation currently works out at around £110-115/m² of floor area.
Timber Frame: A significant proportion of self builders use timber frame construction in place of concrete blockwork. The cost of a standard 89mm timber frame is comparable to the cost of blockwork plus insulation. If you decide to go for a highperformance timber frame, with thicker walls and more insulation (say 140mm frame), the cost will increase by around 10- 15% but with a considerably superior thermal performance.
SIPs: Structural insulated panels (SIPs) offer a high degree of airtightness and insulation. The cost of standard 100mmthickness SIPs is more expensive than blockwork and insulation (manufacturers claim about 1%, although our experts suggest between 7-10%). Thicker panels offer superior energy performance but will add further to the cost.
Green Oak: Oak frame construction is especially popular in the border areas and the southern counties. It is a great way to create instant character in a new house but it is more expensive than concrete cavity walls or timber frame. Expect to pay an additional £40-60/m². You can reduce this cost by combining oak frame with SIPs, or masonry.
Insulated Concrete Formwork (ICF): This is reinforced concrete construction, cast on site using polystyrene moulds that remain in place as permanent insulation. This is a simple system and offers excellent airtightness and efficiency. ICF is marginally more expensive to use than traditional masonry, so allow an extra £20-60/m².
Cladding: The biggest variable in your external walls is not the construction system you choose, but the material you use for the external cladding. In the case of brickwork, prices can vary from £200/1,000 bricks up to £695/1,000 for handmades. It takes 60 bricks/m² of brickwork, so handmade bricks will add at least £28 to every face square metre of external walling, and probably more as handmade bricks are irregular in size and so take longer to lay, meaning labour costs are higher.
Labour costs will increase further if you decide to have a traditional brick bond, such as Flemish bond, with courses of alternating headers and stretchers, rather than a straightforward stretcher bond. If you decide to add details such as stone window cills, heads and surrounds, or brick arches, these features will also increase your build cost considerably.
Adjusting for Cladding Types
|Allowances for Standard Specifications|
|Standard spec – Wirecut bricks (£200/1,000)||£77/m²|
|Good spec – Stock bricks (£250/1,000)||£80/m²|
|Excellent – Sim. Handmade bricks (£350/1,000)||£86/m²|
|Alternative Brick Options|
|Second-hand bricks (£900/1,000)||£118/m²|
|Handmade Bricks (£675/1,000)||£105/m²|
|Flemish bond rather than stretcher||+£5/m²|
|Sawn cropped limestone 125mm (£60²)||£112/m²|
|Reclaimed limestone (£90²||£145/m²|
|Yorkshire gritstone (£58/²)||£105/m²|
|Hung plain clay tiles (£420/1,000)||£112/m²|
|Hung slate (£36/²)||£100/m²|
|Block and sand and cement render||£75/m²|
|Block and polymer render||£100/m²|
|Western redcedar (18mm x 125mm)||£102.50/m²|
|European oak (19mm x 125mm)||£110/m²|
|Whitewood stained (19mm x 120mm)||£93/m²|
|Reconstituted stone window head 215 x 125mm section||£82/m|
|Natural stone window head 215 x 125mm section||£189/m|
|Reconstituted stone door surround 125mm||£1,900/m|
|Natural stone door surround||£6,000|
|Reconstituted stone portico||£6,000+|
|Gauged brick arches (4 courses) high x 100mm section||£200/m|
*All costs per face metre (NB not floor area) except Details costs, which are per linear metre or fixed.
The standard specification for first floors is to use softwood joists covered with flooringgrade chipboard. The cost is £18-19/m². If you opt to use engineered joists such as Ibeams, or beams with a steel web such as Posi-joist, this will add to your costs by £2- 3/m² but the more regular dimensions and improved stability can help avoid squeaky floors. Joists with an open web can help reduce the cost of first fix plumbing and heating, because there is no need to notch or drill joists — but this will only benefit you if you are employing the trades on a day rate, or doing the work yourself.
If you are building a masonry or concrete house you could opt for a concrete first floor structure, using either pre-stressed concrete beams infilled with concrete blocks, or large-format concrete floor panels. This offers superb strength and acoustic separation, and allows you to have masonry first floor walls throughout. This specification will add to your costs by £8- 12/m².
Roofing costs include two main elements — the roof structure, which is typically built in timber; and the roof covering, such as slate, clay or concrete tiles.
The standard specification house includes £75.02/m² for roofing costs and is based on a shallow-pitched roof of just 22.5° spanning between two gable end walls, with trussed rafters made in a factory and large-format concrete interlocking tiles (£1,700/1,000 at 8.2 tiles/m²), plastic gutter and downpipes, and 200mm of quilt insulation. This is about as cheap as it gets, because the lower roof pitch uses minimum timber (shorter rafters) and the roof has a smaller surface area, using less labour and materials for insulation and roof covering. Engineered roof trusses, held together using gangnail plates, are also very cost-effective.
The good quality roof has a steeper roof pitch at 30° which will look more appealing, but makes the rafter lengths longer and so adds to the cost of the trusses — and creates a larger roof area. It also uses more expensive machine-made clay interlocking tiles (£900/1,000 at 20.5 tiles/m²) adding to labour and material costs for roof tiles, felt and batten and insulation, resulting in a cost of £93.77/m².
The excellent quality specification has the same trussed roof but a steeper pitch at 35° and more expensive plain clay roof tiles (£350/1,000 at 60 tiles/m²) pushing the cost up again to £112.52/m².
Roof Pitch The steeper the roof pitch, the larger the roof area and consequently the greater the cost. As a general rule, every 5° increase in roof pitch adds 4% to the roofing cost £/m².
Roof Structure: Changing from a standard ‘fink’ trussed roof to engineered attic trusses will increase the cost by £1,500- 2,500 for the additional timber. A traditional ‘cut’ roof (built on site) would cost roughly the same as attic trusses. Using SIPs for the roof structure in place of trusses is fast and creates maximum useable roof space with a high level of airtightness and thermal insulation. Costs are likely to be slightly higher than for a traditional cut roof or attic trusses.
The cost guides given in the tables are for simple duo-pitched roofs with few junctions. Adding hips, valleys and dormer windows will increase the average cost.
Adjusting for roofing finish
|Allowances for Standard Specifications|
|Standard Conc. I/L tiles, 430 x 380mm||£40/m²|
|Good Clay MM I/L tiles, 340 x 240mm||£50/m²|
|Excel. Clay MM plain tiles, 265 x 165mm||£80/m²|
|Alternative Roofing Options|
|Handmade plain clay tiles 265 x 165mm||£98/m²|
|New Welsh slates 255 x 405mm||£110/m²|
|Reclaimed slates 255 x 460mm||£80/m²|
|Reconstituted Pennine gritstone slate||£70/²|
|New Pennine gritstone slate||£150/m²|
*costs quoted per facing m² (NB not floor area)
Roof Covering: Your choice of roof covering will have a major effect on your construction costs. Speculative builders favour large-format concrete interlocking tiles with a coverage as low as 8-10 tiles/m². Most self builders choose to use more attractive tiles made from natural materials such as clay, slate or stone, which require more tiles per square metre, thus increasing costs.
If you plan to use a roofing material other than that allowed for in the average costs (£40/m² standard, £50/m² good, £80/m² excellent) you need to add an allowance for the net difference in cost. Adding decorative details to the ridges or verges will add to the overall cost.
Foundations and Ground Floor
The cost of foundations is one of the few aspects of housebuilding that you cannot accurately predict until you actually start digging. Unlike other aspects of your build, where you are in total control of the specification, it is the Building Control surveyor who will ultimately decide which foundation solution to accept for your site.
Unlike most costs, which vary according to the quality and size of house you are building, foundation costs per square metre are likely to be more or less the same whatever you build.
Most sites with good ground conditions would be suitable for traditional concrete strip foundations (1m-deep trench, 600mm width, with at least 225mm of concrete), with a reinforced concrete ground slab, insulation, polythene dampproof membrane (DPM), plus blockwork below external ground level and blockwork with facing brick cavity walling up to damp-proof course (DPC). The average cost for foundations and ground floor is £79-81/m², some 7.5% of the total construction cost.
The cost of using trench fill foundations (less below-ground blockwork but more concrete) or a suspended concrete (beam and block) ground floor structure are much the same, both requiring the same insulation and either a minimum 65mm screed finish or a 22mm flooring-grade chipboard floating floor. Variables will be the proximity of your site to the nearest ready-mixed concrete plant, and the nearest tip for removing spoil.
If your site demands a special engineered foundation solution, such as a raft, piles and reinforced ringbeam, or a reinforced slab, allow an extra £10,000 in your budget.
Some things to consider…
Cellars and Basements
The cost of constructing basements varies according to the size and specification of fixtures and fittings. For the purposes of producing a budget figure for your basement, measure the gross internal floor area and use the same costs per square metre as for above-ground space.
The staircase is an opportunity to make an architectural statement, and if this is your intention then you need to make an additional allowance for this above the sum included in the average build costs. The standard specification solution is a softwood staircase consisting of two straight flights linked by a half-landing, with a softwood balustrade, painted or stained, at a cost of around £1,250. The good specification includes a single straight flight in painted softwood at around £1,500, whilst the excellent specification allows for a straight flight in hardwood, with hardwood balustrading at around £2,150. If you build additional storeys, e.g. attic level or basement, you need to allow for additional staircases.
Many modern houses – especially those built by speculative developers – do not include a chimney, largely because of the cost, which starts at £6,100. Many ecological houses also forgo a traditional open flue chimney in favour of a wood burning stove and stainless steel flue, at an installed cost of around £1,650-2,500. Self-builders tend to like to spend on feature fireplaces, and if this is your intention then you will need to make an addition to your budget calculations to account for this. The standard specification has an allowance of £6,100 per fireplace and flue; the good specification has an allowance of £7,600 and the excellent £10,300.
Kitchen Cost Guide*
The excellent quality specification price includes an allowance for a quality kitchen from a mid-market brand name supplier with timber worktops. The good quality specification includes top-of-the-range units from a contract supplier such as Howdens or Magnet with timber worktops. The standard specification includes basic white MDF units with a laminate worktop. You can adjust the cost per square metre figure relevant to your project to suit your choice of kitchen. If you are going for a top-of-the-range designer kitchen then get a price from your supplier, including fitting, and substitute this for the kitchen allowance per square metre.
|Basic range contract fittings||£14-20/m²|
|Top-of-range contract fittings||£40-60/m²|
|Top-of-range brand fittings||£110-120/m²|
Concrete blockwork walls can either be given a traditional two- or three-coat hard plaster finish, or dry-lined using plaster board glued to the walls and then skimmed with a finishing coat of fine plaster, or the joints covered with tape and filler. Timber frame walls are usually finished with plasterboard, with the joints taped and filled, although sometimes a skim coat is applied to even out the walls. Many developers prefer dry-lining on both masonry and timber walls, as it is quicker than hard plastering, which requires time to dry out, and is less prone to cracking from shrinkage or movement. On more expensive schemes, they tend to use traditional hard plaster as it gives a more solid feel. Costs are similar for both wall finish options. If you upgrade to fibrereinforced plasterboard it will add to costs.
The standard specification assumes emulsion paint throughout, with minimal tiling to kitchen and bathrooms at £40- 55/m². The good specification includes more tiling in the kitchen and bathrooms and wallpaper in the living rooms at £50- 65/m². The excellent specification also includes wallpaper to the living room and bedrooms at £60-80/m².
Ceilings are usually covered with plasterboard and finished with a two-coat skim of fine gypsum plaster and emulsion paint at £21-23/m². If you decide to add decorative coving, ceiling roses or other decorative plasterwork you will need to make an allowance for this.
Alternative Floor Finishes*
|Contract quality carpet||£20-25/m²|
|100% wool carpet||£45-55/m²|
|Laminate (wood effect)||£20-25/m²|
|Engineered oak flooring||£60-65/m²|
|Reclaimed pine floorboards||£40-50/m²|
|Natural stone flags||£70-80/m²|
(*Includes labour and wastage)
Most houses include some built-in storage areas. These are already allowed for within the costs at between £20-40/m².
In masonry houses the standard specification is 100mm concrete blockwork and steel or concrete lintels for the partition walls on the ground floor and 38mm x 89mm timber stud walls on the first floor. For timber frame construction all internal walls will be timber frame. High-quality masonry houses with a beam and block first floor structure may have all internal partition walls built in 100mm concrete blockwork.
The standard specification includes hardboard-faced hollow-cored flush doors in softwood frames, hung and decorated at around £325 each including ironmongery. The good specification includes better hollow-cored flush doors in softwood frames (around £360 each). The excellent specification includes hard woodveneered solid-cored doors in softwood frames, at around £450 each. If you plan to fit superior quality doors you will need to allow for this in your budget.
Garages for Houses*
Integral and semi-integral garages should be included with the gross floor area of the house gives costs for rebuilding a range of garages.
|Garage Cost Guide|
(*measurements are for gross external floor area)
Windows and Doors
External joinery is another feature that selfbuilders place a great deal of value on and consequently tend to invest in quite heavily. The standard specification house has offthe- shelf painted softwood casement windows and doors, with double-glazed units and factory-fitted aluminium ironmongery at a cost of £50-60/m². The good specification includes high-performance, off-the-shelf, painted softwood casement windows and doors at £55-65/m². The excellent specification includes double-glazed alum – inium frames in hardwood surrounds and a hardwood panelled front door and good quality ironmongery is £85-95/m².
If you want to go for bespoke windows and external doors, substitute their total price for the allowance (joinery cost for your chosen specification multiplied by your gross internal floor area).
Two storey bay (3.0m² floor area)
|Bespoke Window Costs*|
|Standard modern softwood sash window||£759/m²|
|Purpose-made softwood box sash window||£830/m²|
|Purpose-made hardwood box sash window||£959/m²|
|Single storey bay (1.5m² floor area)||£2,150/£2,700/£3,800 (standard/good/excellent)|
|Two storey bay (3.0m² floor area)||£3,700/£4,600/£6,450 (standard/good/excellent)|
*Costs per facing m²
The standard heating solution is a wet radiator system with a wall-mounted gas condensing boiler, two-channel programmable thermo stat, and thermostatic radiator valves. Smaller houses will have a combination boiler providing instant hot water, whilst larger houses will have stored hot water in a cylinder. A standard central heating system will cost £18-23/m² and this is the allowance in the average build costs. If you decide to install underfloor heating, this works out to be around 15% more expensive, so allow £20-25/m². If you plan to install ecological features, get a full quote and add this in to your budget.
Bathrooms and Cloakrooms
Hot and cold plumbing costs for bathrooms and kitchens etc. are much the same regardless of the specification you choose, but the cost of sanitaryware and brassware varies enormously from £2-300 for a full bathroom suite (bath, basin, WC, taps and wastes) up to several £1,000s. The quality and area of tiling on floor and walls varies from £23/m² upwards, and then you can add showers and enclosures, heated towel rails, underfloor heating, luxury baths, steam rooms, and more. The costs in the tables allow for two bathrooms and one cloakroom at the relevant cost (see below). If you plan to fit more bathroom facilities, or better quality facilities, then use the typical cost allowances below to allow for this.
|Approximate Total Cost||Standard||Good||Excellent|
|Bathroom (including WC, basin, bath and additional plumbing, doors, walls, windows and finishes)||£3,200||£4,900||£7,900|
|Shower Room (including WC, basin, shower cubicle and additional plumbing, doors, walls, windows and finishes)||£3,400||£5,300||£8,600|
|Cloakroom (including WC, basin and additional plumbing, doors, walls, windows and finishes)||£1,900||£2,600||£3,300|
If you plan to add a conservatory to your new home this needs to be priced separately. For rough budget purposes you can use the figures below but once your plans develop you should get a price for design and build and add this to your budget calculations.
|Floor area*||Softwood||White PVCu||Hardwood|
|Mock Georgian Style||10m²||£10,700||£10,400||£14,300|
|Mock Victorian Style||10m²||£10,500||£11,700||£14,100|
If your plot is not connected to mains services you should get quotes for connection from you local utility suppliers before purchasing the site. If there is the option of a mains gas connection, take it. As a budget figure allow £6,000 for connection to water, sewers, electricity, telephone and gas. If the site does not have mains gas you will need to budget an additional £2,000- 2,500 for installation of an oil or LPG tank. If there is no mains sewer you will need to budget for an off-mains alternative such as a septic tank or mini sewage treatment plant — you should find out what the local authority will accept and get a price from suppliers. Allow £3,000-4,000 for a three-four person household and £4-6,000 for a larger household.
Electrics Cost Guide
Standard electrical installation costs do not vary much from house to house other than by scale, as all houses use the same cabling, smoke alarms, extract fans and in most cases, standard pendant light fittings. Generally, the better quality the house, the more power sockets, phone and TV points there are and so the average cost per square metre for electrics increases.
If you decide to fit low-voltage downlighters, decorative light fittings, anything other than standard white plastic sockets and switches, automated lighting controls, a whole-house structured cabling network (Cat 5e), multi-room hi-fi, amp circuits for table lamps, or outdoor garden lighting you will need to make an allowance for these upgrades.
|Electrical Additions||per room|
|Low-voltage downlighters (7)||£350-400|
|Structured cable network||£200-250|
|Separately switched 2a lamp circuits||£250-350|
|Security alarm system||£400-1,000+|