Made to Measure

SIP Panel Extensions

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Everything but the painting
Builds completed in less than 2 weeks
10+ year guarantee
Nationwide coverage

SIP Extensions

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(Sizes shown are approximate & full sizes are shown in the product specification)

We supply and install custom SIP house extensions that expand your home with style. Built from the ground up, using Structurally Insulated Panels (SIPs), each SIP panel extension enables exceptional insulation, airtightness, long-term durability and affordability compared to traditional extensions.

After a complimentary site visit, our team will plan, design and build your extension to measure, complete with our standard inclusions and any optional extras you select. We handle every stage of the process, including planning permission and installation, so your new living space is ready to use without the stress or the heavy lifting.

Every SIP extension is fully finished with a host of optional extras available to choose from, seamlessly blending with your existing property while enhancing both its appearance and functionality. These year-round builds can easily act as a functional home office, man cave, music room, home gym, self-contained annexe or whatever else. Speak to a member of our team today to arrange your free site visit and start planning your bespoke SIP extension.

100mm Structural Insulated Panels (SIPs) – Installed throughout the walls (using 150mm SIPs), floor (using 100mm SIPs) and roof for superior strength and insulation. An insulated timber roof is used instead of SIPs when skylights or lanterns are required.

UPVC Windows and Doors – Supplied in your chosen size, design and colour for durability and energy efficiency. Optional upgrade to aluminium bi-fold doors available.

Professional Plastering – Smooth, high-quality plaster finish as standard.

Internal and External Electrics – Includes all wiring, sockets and lighting for immediate usability.

EPDM Rubber Roof – Long-lasting, watertight and low-maintenance roofing for maximum protection.

Fire-Rated Materials – Installed on any wall within 1m of a boundary to comply with building regulations.

UPVC Fascias, Soffits and Guttering – Provide a clean, low-maintenance finish that complements your property. Available in your chosen colour.

Flooring and Skirting – Quoted and installed as part of your final specification, if required.

Aluminium Bi-fold Doors – Open up your space with wide, modern access and improved natural light.

Skylights and Roof Lanterns – Add natural daylight and enhance the feeling of space inside your extension.

Plumbing – Include a fully-functional kitchen unit, sink, toilet or shower to create a functional annexe or utility room.

Partition Walls – Divide the space into functional areas such as an office, living space, man cave or home gym.

Internal Plastering and Cladding – Choose from plaster, timber cladding, rendering or composite finishes to match your interior design.

Internal Flooring – Laminate flooring and skirting options available.

Roof Overhang – Extend the roofline to create a sheltered outdoor space or a feature canopy.

Canopy Extension – Add covered seating, storage or a transitional outdoor area.

External Finishes – Choose from Canadian Western Red Cedar, English Cedar, Fibre Cement Cladding, Brick Slip or Composite Cladding (available in 8 colours). Rendering options include Monocouche or Silicone Render, both offered in a range of colours.

Groundworks – Reinforced concrete base included as standard with ground screws available on request (subject to building control).

Each SIP extension is supplied and fully installed by our skilled in-house team for a complete, turnkey service. We don’t deliver panels for you to assemble – we handle everything from groundworks and base preparation to finishing and final handover.

Before starting, we’ll arrange a free site visit to assess your property, discuss your ideas and confirm the best layout, specification and finishes for your space.

If planning permission or building regulations approval is required, our team will assist with the application to keep your project compliant and straightforward.

Once approved, we take care of every stage of construction, from SIP installation and roofing to electrical works and interior finishes. Our motto is ‘everything but the painting’!

Typical lead time is around 2 – 3 weeks for all custom SIP house extensions.

What is a SIP extension?

SIP extensions are structures built using SIPs (structural insulated panels. These panels consist of an insulating foam core embedded between two structural facings, which helps to regulate the temperature of a build, keeping rooms warm during the winter and cool during the summer.

Our SIP panels used in our extension builds are produced under factory-controlled conditions which ensures maximum strength and durability, capable of withstanding exposure to the elements and preserving the classic, wood-finish they offer.

Do SIP extensions need foundations?

SIP panel extensions do not require the same traditional footings as brick and block extensions. On average a 150mm concrete slab is sufficient at providing a foundation for a SIP extension build, however this will be assessed and determined during any site visits or routine inspections.

Do you need planning permission for a SIP extension?

Typically, most small single storey rear extensions do not require planning permission and can be built under permitted development. However, there are stipulations to this and rules do vary depending on your area.

Most semi-detached houses find they can extend to the rear 3m and detached houses 4m before planning is required. The build should not occupy more than 50% of your garden space, be less than 4m in height (3m if within 2m of a boundary) and must not exceed the existing house’s eaves or ridge.

We do always advise a quick check with your local council to determine your individual permitted development rights prior to any building work. Should planning permission be required, we can help assist with this process however this would need to be applied for direct to the relevant parties.

How high can you build with SIP panels?

SIPs can be used to build up to 4 storeys high, however at present we only offer single storey SIP extensions and garden rooms.

How long do SIP house extensions last?

If properly maintained and sufficiently protected from environmental factors, SIP panels composing your extension can have an estimated lifespan of well over 60 years. They are a trusted construction materials used in building both modern residential and commercial properties, and this can be attributed to their strength and energy efficiency properties.

What is the best cladding for SIP house extensions?

We offer a wide range of external finishes for your custom SIP extensions including Composite Cladding, Fibre Cement Cladding, Canadian Red Western Cedar, Render and Brick Slips. Each comes with its own aesthetic and physical properties. Our diverse range means you won’t have trouble matching or complement your SIP extension to your existing house structure.

Are SIP panels load bearing?

SIP panels are engineered with loadbearing capabilities and because of this, they can can be used as full structural external walls and load bearing internal walls. SIPs are up to 7x stronger than timber framed builds and up to 3x stronger than brick and block.