Annex Kits – Landing Page

WINTER SALE
Limited Winter Offer

6.1m × 4.27m RD SIPs Annex Kit

Create more space this Winter with an RD SIPs Annex Kit. This complete annex kit is designed to provide a practical, comfortable and energy-efficient building shell, giving you the perfect starting point for creating additional space at your property.

6.1m × 4.27m Annex Kit Includes a generous 0.61m roof overhang for a practical and attractive finished appearance.

Create the Space You Need

Whether you're looking to create self-contained family accommodation, guest accommodation, space for relatives, a home office, studio or additional living space, this RD SIPs annex kit provides a highly insulated structural system to get your project moving.

What's Included

  • 6.1m × 4.27m building footprint
  • 0.61m roof overhang
  • 147mm PUR-bonded SIP panels
  • High-performance insulated construction
  • U-value of approximately 0.18 achievable
  • Designed around your project requirements
  • UK manufactured SIPs
  • UK-wide supply available

Winter Sale

Make the most of our Winter sale and secure this 6.1m × 4.27m RD SIPs Annex Kit with a 0.61m roof overhang. Get your project started and create the extra space you've been looking for.

With approximately 26m² of floor area before allowing for wall thickness, this kit offers a substantial amount of additional space while taking advantage of the speed and thermal performance of SIP construction.

Enquire About the Winter Sale →
RD SIPs Annex Kits

Why Buy an RD SIPs Annex Kit?

Whether you’re creating extra living space for family, a private guest suite, or a self-contained annexe, an RD SIPs annex kit gives you a fast, energy-efficient and practical way to build.

Our Structural Insulated Panel (SIP) annex kits are designed to make construction quicker and more predictable while creating a comfortable space that can be enjoyed throughout the year.

Faster Construction Prefabricated panels designed for efficient assembly on site.
Energy Efficient Highly insulated construction designed for year-round comfort.
Designed For You Annex kits designed around your project requirements.
01

A Faster Way to Build Your Annexe

SIP construction combines structural strength and insulation within a prefabricated panel system. Because your annex kit is designed around your project and prepared before arriving on site, the main structure can be assembled much faster than many traditional construction methods.

  • Faster to erect than many traditional building methods
  • Reach the weather-tight stage sooner
  • Reduced time on site can help lower labour costs and disruption
  • Ideal where building work is taking place alongside an occupied home

Designed for efficient construction

SIP panels combine structure and insulation into one engineered building system, helping to simplify the construction process and reduce the amount of work required on site.

02

A Warm, Energy-Efficient Space

An annexe should feel like a proper part of the home, not an outbuilding that’s difficult or expensive to heat.

SIPs create a highly insulated building envelope designed to retain heat and provide comfortable internal temperatures throughout the year.

0.18
U-value achievable with 147mm PUR-bonded panels
  • 147mm PUR-bonded panels can achieve a U-value of 0.18
  • Reduced heat loss can help lower ongoing heating requirements
  • Excellent thermal performance for year-round use
  • A comfortable environment for living, working or accommodating family
03

Professional-Grade Panels with Real Certification

The quality of an annex kit starts with the panels behind it. RD SIPs supplies certified SIP panels manufactured to audited standards, giving you confidence in the system being used for your project.

Structural Timber Association
(STA) Member
CAT G
SIP Mark Systems
ISO 9001
Certified
STA Assure
Silver
Made in
Britain
04

Predictable Quality, Manufactured in Controlled Conditions

Traditional construction can be affected by weather, site conditions and variations in workmanship. SIP construction moves much of the preparation into a controlled manufacturing environment.

01

Controlled Production

Panels are produced in controlled conditions to help maintain consistent manufacturing quality.

02

Traceability

Full material and production traceability helps provide greater confidence in the system supplied.

03

Workshop Dry-Fitting

Panels can be dry-fitted in the workshop to help reduce potential errors before they reach site.

04

PUR Auto-Bonding

PUR auto-bonding helps prevent delamination and supports the integrity of the panel system.

05

Accurate Manufacturing

Precise manufacturing helps simplify installation and assembly on site.

06

Less Site Disruption

Efficient panel assembly can help reduce the duration and disruption associated with construction work.

05

Designed Around Your Annex Project

Every property and every annexe is different. Your SIP kit can be designed around the dimensions, layout and requirements of your project rather than forcing you into a one-size-fits-all structure.

Whether you’re planning accommodation for relatives, additional guest space or a larger self-contained annexe, our team can help you develop the right SIP solution.

  • Guidance through the design and planning stages
  • Advice on foundations, openings and roof design
  • Kits designed around your project requirements
  • Installation and best-practice fitting guidance
06

Less Waste and a More Efficient Approach to Building

SIPs can provide a more efficient construction method both during the build and throughout the life of the annexe.

  • Precise off-site manufacturing can help minimise site waste
  • Highly insulated construction helps reduce ongoing energy demand
  • Faster assembly can mean fewer days of construction activity on your property
  • Efficient use of materials through a pre-designed panel system
07

Clear Lead Times and Straightforward Supply

Once the design is agreed, your annex kit can be manufactured and prepared for delivery to site.

4–8 Weeks Typical Supply Time

House and building projects are typically supplied within 4–8 weeks, subject to design and scheduling.

UK-Wide Supply Available

Delivery planning and communication throughout the design and manufacturing process.

  • Clear communication throughout the design and manufacturing process
  • Delivery planning to help make installation as straightforward as possible
08

What’s Included in an RD SIPs Annex Kit?

Your annex kit is designed around your individual project and can include the structural SIP components required to create the building envelope.

Floor, Wall & Roof Panels Panels designed specifically around the requirements of your project.
Panel Specifications Specifications covering thickness, performance and certification.
Delivery Planning Support Support covering access and handling considerations for delivery.
Technical Guidance Guidance to help your team install the SIP system correctly.

Create the Extra Space Your Property Needs

Whether you’re planning a self-contained annexe for a family member, additional guest accommodation or simply need more usable space, SIPs offer a fast and energy-efficient way to bring the project to life.

Send us your drawings, or provide a sketch and dimensions. Tell us your location and target timescale and we’ll advise on the appropriate panel specification, lead time and provide a clear quote.

Talk to RD SIPs About Your Project →
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