Skip to product information

MPN: GX450/90B

Estimated Delivery: 3 - 5 Working Days

Grant Green System External High Level/Vertical Flue Extension C/W Locking Band

Grant Green System External High Level/Vertical Flue Extension C/W Locking Band


Regular price £97.79 Excl. VAT
£117.35 Incl. VAT
Sale price £97.79 Excl. VAT
£117.35 Incl. VAT
Regular price
*For business & Trade Accounts only.
Want it processed today? Order within:

Safe & Secure Payments

Payment methods
  • American Express
  • Apple Pay
  • Diners Club
  • Discover
  • Google Pay
  • Klarna
  • Maestro
  • Mastercard
  • PayPal
  • Shop Pay
  • Union Pay
  • Visa

Key Information

Product Information

Grant Green System External High Level/Vertical Flue Extension C/W Locking Band

The Grant Green System External High Level/Vertical Flue Extension is designed to provide additional length for compatible external oil boiler flue installations. As part of the GX Series, this extension is suitable for high-level and vertical flue arrangements, giving installers greater flexibility when configuring the flue system. Manufactured from stainless steel and finished in black, the extension is designed to provide a durable solution for external installations. Each extension is supplied with a locking band to help secure the connection between compatible flue components.

Available Variants

The range includes three options to suit different boiler outputs and installation requirements. For 12-26kW boilers, the extension is available in both 450mm and 950mm lengths. For 26-70kW boilers, a 950mm extension is available. This selection allows installers to choose an extension that matches the required flue length and compatible boiler output.

Designed for External High-Level and Vertical Flues

The Grant Green System extension is intended for use in external high-level and vertical flue configurations. It provides additional length where required and can form part of a modular flue arrangement designed to suit different installation layouts. The extension is designed for use with compatible oil-fired boilers and should be matched with the appropriate Grant flue components for the installation.

Durable Stainless Steel Construction

Made from stainless steel, the extension is designed to withstand the demands of an external installation. The black painted finish provides a discreet appearance, while the supplied locking band helps create a secure connection between compatible components. The extension is compatible with the EZ-Fit series, making it a useful component for suitable Grant flue system configurations.

Key Features

  • External high-level/vertical flue extension
  • Part of the Grant Green System and GX Series
  • Designed for use with oil-fired boilers
  • Suitable for 12-26kW and 26-70kW boiler outputs
  • 12-26kW variant available in 450mm length
  • 12-26kW variant available in 950mm length
  • 26-70kW variant available in 950mm length
  • Manufactured from stainless steel
  • Black painted finish
  • Supplied with locking band
  • Compatible with the EZ-Fit series
  • Designed for external high-level and vertical flue installations

Frequently Asked Questions

What lengths are available for the Grant Green System flue extension?

For 12-26kW boilers, the extension is available in 450mm and 950mm lengths. For 26-70kW boilers, the available option is 950mm.

What boiler outputs is this flue extension suitable for?

The extension is available for compatible oil-fired boilers with heat outputs of 12-26kW and 26-70kW. The correct variant should be selected according to the boiler output and flue system requirements.

What is included with the Grant Green System extension?

Each extension is supplied with a locking band to help secure the connection to compatible flue components. The extension itself is manufactured from stainless steel and has a black painted finish.

Why Choose Us

At JJ Building Materials, we're committed to supplying quality building products at competitive prices, backed by the service and expertise you'd expect from an established independent merchant. Whether you're a trade professional managing large-scale projects or a homeowner taking on a DIY renovation, we're here to help you find the right products for the job.

As part of the JJ Roofing Supplies Group, we build on decades of experience supplying construction materials across the UK. We've expanded beyond roofing to offer a growing range of building materials, including timber, insulation, landscaping products, plumbing supplies, flooring, doors, bricks, fencing, garden buildings and much more – all available to order online with nationwide delivery.

We work with many of the industry's leading manufacturers to bring you trusted products that meet the highest standards of quality and performance. Our team is passionate about providing excellent customer service, competitive pricing and a straightforward shopping experience from start to finish.

When you shop with JJ Building Materials, you can expect:

  • Competitive prices on leading brands and quality products.
  • Nationwide delivery across the UK
  • A constantly expanding range of building and landscaping materials.
  • Friendly, knowledgeable customer support.
  • A trusted business backed by the JJ Roofing Supplies Group.

Delivery

Every order is personally reviewed by our experienced team to ensure everything is correct before dispatch. We offer delivery from as little as the next working day on selected products, so please refer to the dark blue Estimated Delivery box above for the expected delivery timeframe for this item.

We work with trusted manufacturers and specialist delivery partners to ensure your order arrives safely and on time. You'll receive tracking details once your order has been dispatched, and if we need to confirm any delivery details, one of our team will contact you directly to keep everything running smoothly.

Roof Tiles & Fittings:

We recommend ordering an additional 10% of roof tiles to allow for any breakages that may occur during delivery or handling. Roof tiles are naturally fragile, and having a few extra on site helps prevent delays and ensures your roofing project can be completed without interruption.

Multiple Products from the Same Supplier

If you're ordering multiple products from the same supplier, your order will be dispatched together once all items are ready. This means the longest lead time will apply.

If you need part of your order sooner, please call us on 01202 113233. We can arrange a split delivery, although an additional shipping charge will apply.

Grant Green System External High Level/Vertical Flue Extension C/W Locking Band

£97.79

Can I collect this product from a local branch?

Absolutely. Check availability at your nearest branch during checkout or contact us directly.

Do you offer bulk pricing or trade discounts?

Yes, we offer competitive rates for trade customers and bulk orders. Contact our team for a tailored quote.

What if the product arrives damaged?

Please notify us within 48 hours of delivery. We’ll arrange a prompt replacement or refund as needed.

How fast is the delivery time?

Most items are delivered within 2–5 working days, depending on stock and location. Some products may take longer times.

What is the Return Policy?

We accept most returns within 14 days of delivery, provided the items are unused, in their original packaging, and in resalable condition. Please contact our customer service team to arrange a return or discuss any concerns.