Create a warm, modern living space with a high-performance SIPs annex kit built for comfort, strength and long-lasting value — all fully compliant with UK building regulations.
If you’re planning an annex, you usually want three things: speed, comfort, and certainty. Whether it’s for family, guests, a home office with a bathroom, or a small rental (where permitted), a SIP annex kit is a simple way to achieve a high-performance build without a long, disruptive programme.
At RD SIPs, we supply certified SIP panels and annex kits with practical support — helping you move from drawings to a weather-tight shell quickly and with fewer surprises.
A SIP annex kit is a pre-designed (or custom-designed) package of Structural Insulated Panels (SIPs) for walls and roofs, supplied as a coordinated system so the structure goes together efficiently.
SIPs are made from:
Because SIPs combine structure and insulation in one system, annexes built this way are typically faster, more thermally efficient, and more consistent in quality when installed correctly.
Annexes are often used daily, not just occasionally. SIPs help create a space that feels like a true extension of the home, with strong insulation and reduced cold spots.
Common uses include:
Once the base is prepared, SIPs are designed to go together quickly and accurately.
A well-designed SIP annex can be more efficient to heat than traditional builds, depending on the overall specification.
Performance depends on:
The principle is simple: good insulation combined with good detailing leads to reduced heat loss.
SIPs allow for a wide range of designs, making them ideal for annex projects with more ambitious layouts.
Panels are manufactured to size, reducing the need for cutting on site.
Annex projects often require planning permission and must meet Building Regulations, particularly if the space is habitable.
Requirements vary depending on:
If you’re at an early stage, we can help you understand what information you’ll need before placing an order.
SIPs are straightforward to work with, but getting the basics right is essential. The most common issues include:
We provide clear guidance to help you avoid costly mistakes and delays.
We’re a modern, family-run supplier based in Herefordshire, built to support projects that larger SIP manufacturers often overlook.
If you’ve got drawings (PDF preferred) or even rough dimensions, send them over and we’ll help you determine the best approach and provide a clear, honest quote.
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