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InstaBuild Extensions

Get Your Designs

Using Ultraframe’s partnership with the Great British Ground Screw Company, we now offer fully fitted InstaBuild Extensions packages to customers across Clevedon and the South West. With a choice of 3 popular style options, our package includes a hup! base system, hup! walls and an Ultraframe roof. Enhance your home now with our InstaBuild Extension with Britannia Windows today!

What's Included in Your InstaBuild Extension Package?

Working with Ultraframe, one of UK’s trusted and leading names in pre-fabricated extension systems, discover what our packages include:

hup! Base System

  • Pre-fabricated steel frame construction, pre-approved by Building Control.
  • Highly insulated, meeting current UK building standards.
  • Moisture resistant chipboard flooring to accept your floor coverings.
  • Faster to install than traditional foundations.

 

 

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hup!

hup! Wall Systems

• Super-insulated and ready for cladding, replica brick mesh or render.
• Delivers outstanding thermal performance.
• Stronger than brickwork.
• Pre-approved by Building Control.

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Ultraframe Roof Systems

• Customisable options for solid or glazed roofs.
• Designed for strength, insulation and aesthetics.
• Configurable – Choose where you want the glass to let light in.
• Pre-approved by Building Control.

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Cutting Edge Technology

InstaBuild Extensions are built using innovative technology that meets all UK building regulation standards and is BBA approved.

Fully Equipped Package

Everything in our InstaBuild Extensions include hup! base, hup! walls, an Ultraroof, ground screws, windows, doors and installation.

Quick Installation

InstaBuild Extensions come pre-fabricated off site to speed up build times, with extensions built in as little as 2 weeks!

25 Year Guarantee

InstaBuild comes with a 25 year GBGS guarantee so you can be assured you are investing in a worthwhile extension with a long-lasting base.

Year Round Installation

Can be built at any time during the year, even in the winter months.

Happy Customers

Lady drinks coffee and watching through windows and doors

© 2026 Britannia Windows (UK) Ltd. All rights reserved

Britannia Windows is a trading name of Network Britannia Limited, registered in England and Wales, company no. 06546357, VAT No. 937200539 whose registered office is Kimberley Road, Clevedon, North Somerset, BS21 6QJ. Credit is subject to status and affordability. Terms and conditions apply.