A self build house kit or prefabricated kit home is an attractive self build option, with bespoke designs and fast build times.

 A guide to prefabricated kit homes

Image: Richard Powers. Built using a fully digital design and production process, this two-storey eco house in Greenwich, south-east London by Facit Homes (020 3034 0720; facit-homes.com) cost £500,000 to build. Sheets of structurally graded engineered plywood were cut on-site by a computer controlled machine, saving time and keeping waste to a minimum. The airtight building also has triple glazing and a mechanical ventilation and heat recovery system (MVHR).

Twelve years ago David and Greta Iredale’s innovative Huf Haus project was first featured on Channel 4’s Grand Designs, showcasing the many benefits of the prefab method of house building.

Since then, the awareness and popularity of self build kit homes in the UK has been on the up, with many self-builders realising the advantages of this speedy construction method. Prefabs involve varying degrees of off-site construction – depending on the build method and supplier – before being erected on your plot in what can be a matter of days.

And rather than offering a range of standard options, many manufacturers will adapt existing designs to suit your preferred style and layout, or offer a completely bespoke solution. 

The combination of clear pricing, eco-friendly benefits and efficient build processes makes it easy to see the appeal of a kit home; it offers self-builders the chance to create a unique home for a fixed cost.

We round up 

Do your house kit design research 

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Image: Richard Powers. Set in a north London conservation area, this Baufritz home blends a traditional front with a Modernist- inspired rear elevation. Built to replace an inefficient older property, the five-bedroom house was watertight within three days and has PV panels, rainwater harvesting, mechanical ventilation with heat recovery and triple glazing, giving its owners the eco-friendly home they wanted. (01223 235 632; baufritz.co.uk)

The most common route to take when building a prefab (especially if you’re working with a non-UK company) is to use its own in-house design team.

Research the types of properties that each company has designed and built in the UK to see if its work  fits with what you want to achieve. Alternatively, you could use an independent architect to draw up a design before liaising with your chosen manufacturer.

It’s worth bearing in mind, however, that an in-house design team will have useful experience and extensive technical knowledge of designing prefab homes. 

Knowing the measurements of standardised wall panels and windows that its company usually works with, for example, will help to ensure the build is as cost-effective as possible.

Self build kit home methods

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Image: Richard Powers. Based on a traditional agricultural barn, this Cotswolds property was designed by an independent local architect and built by Hanse Haus (0800 302 9220; hanse-haus.co.uk). Fabricated in the company’s German factory, the house was erected within  five days and features a combination of pressure-treated pine and Corten steel facades and a zinc roof. It cost £1,445 per sqm.

Prefab homes are typically constructed from a timber frame or a timber closed-panel system (similar to structural insulated panels or SIPs) where the wall and roof panels are made on-site, filled with high levels of insulation and, in some cases, fitted with exterior cladding and internal wall finishes.

You can choose from various build packages that can be tailored to suit your requirements, offering you as much or as little involvement as you want.

You could opt for supply and installation of the frame or shell of the building only, right through to a full turn-key solution where the house will be designed, built and completely fitted out.

‘The majority of our customers opt for the complete package as most people want a unique, high-quality project that’s as hassle-free as possible,’ says Oliver Rehm, UK managing director at Baufritz.

How long does a prefab kit house take to build?

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Image: Richard Powers. Built on agricultural land that the homeowners’ family has farmed since the Fifties, this bespoke three-bedroom timber-frame home by Potton (01767 676 400; potton.co.uk) is clad in oak harvested from the woodland next to the property. The owners chose the option of a timber frame as they liked the idea of the speed and ease of the build. The frame for a house of this type would typically be erected on site within two weeks and a similar project would cost from £180,000.

If you choose the full design and build option, the process will involve several meetings with the architect and project manager to discuss initial ideas and to finalise plans; companies such as Baufritz, Huf Haus and Hanse Haus then offer a visit to their showrooms and factories, all based in Germany, to choose the interior fittings for the house.

Once the groundworks are completed, a typical prefab house can be erected on site and made water- and weather-tight within just two to three days.

‘This fast build time means there’s minimal disruption for neighbours, too,’ says Rehm. ‘There will be only a couple of days when there are large lorries and a crane on site, and then, for the rest of the project, it’s just smaller vans.’

Once the shell is built, the finishing teams will come on site to complete the project, including the interior kit-out, which can take anything from around three months for a smaller three-bedroom house to six months for a larger property.

Advantages of prefabricated kit homes

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Image: Richard Powers. Constructed from SIPs and clad in a Siberian larch rainscreen, this four-bedroom property in rural Scotland by Heb Homes (0141 550 7360; hebrideanhomes. com) has large windows for solar gain. Built as part of the company’s turn-key package, it took five months to construct the house and complete the interior fit out, at a cost of around £250,000.

In addition to the fast build time, creating a house from component parts made in a controlled environment such as a factory takes away many of the variables that can cause delays with more traditional build methods.

With all the materials readily available in storage, and no weather delays to contend with, it’s far easier to predict accurately the total cost of the project.

‘Having a set price and a fixed delivery date when they will receive the keys to their finished house is often what gives people the confidence to start their project,’ adds Rehm. ‘It’s one of the main reasons people choose this route when self-building.’

Consider the finer details of your self build kit home

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Image: Richard Powers. Showcasing the expanses of glass that are synonymous with Huf Haus architecture, this property in Weybridge, Surrey, has been designed to be incredibly energy efficient thanks to high levels of insulation and airtightness. It also features an innovative new heating system, which harvests the energy produced when ice turns to water. The structure was watertight within three weeks, and a similar-sized high-spec property would cost around £1.5million to build. (01932 586 550; huf-haus.com)

A fully prefabricated property often requires more time for the initial design process than other types of build project, because in many instances final details, such as the location of plug sockets and light fittings, will need to be decided before any of the component parts are produced in the factory.

You’ll also need to bear in mind that the initial groundworks will usually be completed by a separate contractor, typically employed by the homeowner. Most house manufacturers will be able to help with sourcing a suitable company, and will also liaise with the contractor over what is required in terms of foundations prior to the arrival on site of the structural components of the property.

How much does a self build house kit cost?

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Image: Richard Powers. Designed by Roderick James Architects (01803 868 000; roderickjamesarchitects.com) this one-bedroom eco-build on the Gower peninsula is made from a traditionally pegged oak frame by Carpenter Oak (01803 732 900; carpenteroak. com), with prefabricated wall panels and larch cladding. A similar-sized project would cost around £2,500 per sqm.

With so many variations in the build methods and packages offered, it’s difficult to list a definitive price for a prefab house, especially as this will depend on the company’s level of involvement in the project.

For a full turn-key project, however, you’ll be looking at a minimum of around £1,200 per sqm, while companies such as Baufritz and Huf Haus at the top end of the market will cost £2,000 per sqm and upwards.

Do make sure when comparing prices, however, that the specification of the package being offered is the same.

Words: Dominic Bradbury.

Have you built a kit home? Share your experience by tweeting us @granddesignsmag or post a comment on our Facebook page


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