Create the extra space your family needs with a premium SIPs house extension — fast to build, fully insulated, and designed for year-round comfort.
A SIPs (Structural Insulated Panels) extension is a modern way to add space to your home with less disruption, a faster build programme, and a warmer end result. SIPs combine structure and insulation in one engineered panel, so you get a high-performance building envelope without relying on lots of separate layers being installed perfectly on site.
If you’re planning a kitchen-diner extension, a larger living space, or an extra bedroom, SIPs are a smart option when you want speed, comfort, and predictable performance.
One of the biggest reasons people choose SIPs for extensions is speed. Panels are designed and manufactured to suit your project, then delivered ready to assemble.
That can mean:
For many households, reducing disruption is just as important as the final space.
Extensions can sometimes feel colder than the original house—especially if insulation and airtightness details aren’t done well. SIPs help avoid that because the insulation is continuous through the wall and roof panels, reducing cold spots and weak points.
A well-built SIPs extension typically gives you:
With SIPs, the thermal performance is part of the panel system, not an afterthought. That consistency makes it easier to plan for building regulations and to achieve the performance you expect.
As a practical example, a 147mm PUR-bonded SIP panel can achieve a U-value around 0.18, which is suitable for many UK building regulation requirements.
Most extensions today include features like large glazing, bifold or sliding doors, and open-plan kitchen-living spaces. SIPs work particularly well for these designs when the structure is properly engineered.
SIPs extensions are commonly used for:
Airtightness is a major factor in comfort and running costs. SIPs can make airtightness easier to achieve because there are fewer junctions and fewer opportunities for small gaps compared with more traditional build-ups.
A more airtight extension often means:
Because SIPs are cut to suit the design, there’s usually less offcut waste on site. That’s helpful on an extension where access is tight and everything happens right next to your home.
You’ll often see:
SIPs don’t remove every unknown in a building project (groundworks and existing house tie-ins can still throw up surprises), but they do make the superstructure more predictable.
A defined kit and clear build sequence can help reduce:
SIPs work best when the fundamentals are right. A high-performing extension depends on:
If you want an extension that goes up quickly, feels warm and comfortable, and delivers predictable performance, SIPs are hard to beat.
Done properly, a SIPs extension gives you a modern space that looks great, costs less to run, and causes less disruption during the build.