From traditional systems to modern methods of construction, find out what you need to know to choose a build style for your self build project.
Image: This five-bedroom modular home in North Connel, near Oban in Scotland, is constructed from sound and insulation-efficient structurally insulated panels (SIPs) and was designed by Scottish architect Dualcha. Photo: Hebridean Homes
When embarking on a self build, one of your first considerations is the construction system that will form your home’s superstructure – it will have implications on every aspect of your self build project – including cost, erection speed, internal layout and even the level of energy efficiency.
From traditional systems like brick and block, to contemporary prefabricated methods, every route has its own pros and cons. Your selection will be down to personal taste and what suits your design. So, what’s the difference between the most popular routes available?
Brick and block
Image: This self build home which featured on Grand Designs in 2018 was rebuilt and extended using a brick and block construction method. Photo: Fraser Marr
Brick and block cavity walls are the most used building method for new homes in the UK. The system comprises an internal leaf of structural blockwork and an external brick face, held together at fixed points with wall ties. The two elements are separated by a cavity that prevents moisture ingress and can be packed with plenty of insulation. The dense nature of brick means that it has high levels of thermal mass, allowing the building fabric to absorb heat during the day and let it out into the house for hours after dark, creating a stable and comfortable internal environment.
Many self-builders are drawn to the system due to its familiarity in the UK – there’s a wealth of tradespeople who specialise in masonry builds, making it fairly easy to find a local professional offering a competitive rate. Materials for this type of construction are easy to come by and you’ll be able to find local merchants holding plenty of stock to cater for a typical project.
In terms of aesthetic choice, this versatile system lets you employ a series of variations to ensure you can get the look you want. You can use stone for the external leaf, slimline linear bricks for a contemporary exterior or you can even colourmatch your masonry to exactly mimic heritage mixes.
All the hard work is carried out on site, with the two masonry leaves being built up in courses from the footings. Depending on the size of your new home, brick and block can take 20 weeks or more to finish. As bricklaying is a wet trade, it’s at the mercy of our climate – the mortar, which will be around 10mm thick, takes time to cure and can fail if it’s laid in freezing or very wet conditions.
Read more: How long does it take to build a house?
Image: The first of its kind on Tyneside, Oak Tree Passivhaus by MawsonKerr has a breathable twin timber frame filled with sustainable high-performance mineral wool insulation and uses stone sourced from its sloping site. Photo: Jill Tate
In this system, the frame acts as a superstructure, supporting the entire building, so there’s no requirement for internal load-bearing walls. This allows you to choose between openplan or partitioned internal layouts – and you can reconfigure them cost-effectively if your requirements change in the future.
There are several different timber construction methods to choose from, including green oak, post and beam and conventional open or closed panel timber frame – all of which are prefabricated off site. Erecting a timber frame is a specialist task, and one that self-builders shouldn’t take on themselves. With this in mind, most specialist firms will require you to commission them to both fabricate and erect the frame, taking it at least to watertight stage.
A basic package will take about 12 weeks to produce from the design stage. And, while it may take less than a week to physically manufacture all the component parts, there’s much to do before this part of the process can commence. The design has to be finalised, planning approved, a Building Regs application submitted, and so on. Yet, once on site, even the largest of projects should be completed to watertight in under two weeks.
Insulating concrete formwork
Image: This self build, which featured on Grand Designs back in 2018, was constructed with cost-effective and energy-efficient insulating concrete formwork, but finding structural engineers and builders familiar with ICF held up the progress of the build.
A modern masonry system, insulated concrete formwork (ICF) involves stacking a series of hollow blocks (usually made of expanded polystyrene) to create a mould that can then be pumped full of readymixed concrete. Once the concrete is set, the structure can then be finished in your choice of cladding - however, it is watertight at the envelope stage, meaning that other trades can begin work even without the cladding affixed.
ICF has good levels of insulation built-in and offers impressive acoustic qualities.
If you want to be hands-on with your self-build this may be the ideal route for you – with a little training (often offered by the ICF supply companies) self builders can undertake much of the labour themselves. The trick is getting the first course absolutely level, so it’s worth getting professional assistance at this stage, as any adaptation further down the line will be more difficult to remedy.
ICF is a quick-build system, so even if you employ skilled workers for the duration of the build, you can still save on labour costs in comparison to brick and block. The build time for the form can be as little as two to three days.
Image: This self build property, created by Footprint Architects, was constructed using pre-fabricated timber SIPs, allowing for speedy on-site building within 3 weeks. Photo: Alex Campbell.
For a modern update to traditional timber frame systems, structural insulated panels (SIPS) are made up of two layers of oriented strandboard (OSB) bonded around an inner core of insulation. SIPs come as individual panels for walls, floors and roofs, or in kit form, ready to be joined together to make a whole house. In addition, SIPs are suitable for creating truss-less roofs for liveable loft space, which will make best use of available height in your home.
SIPs allow excellent air-tightness for a build, and insulation is built into the structure; however, due to the requirement for precise measurements, any issues with alignment will lead to delays.
These precision-engineered panels are prefabricated in a factory, which makes for time and labour cost savings on site – experienced teams can erect the structure of a SIPs house in as little as three days.
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