Description

The Single Storey Extension/Outhouse Flue Kit – 5" Twin Wall Flue (125mm) is an all-in-one chimney flue solution designed for installing a wood burning stove in a single-storey extension, outhouse or garden shed. Supplied with the essential components required to create a complete twin wall flue system, this kit provides a convenient and installer-friendly solution while helping to simplify the installation process. The 125mm (5") twin wall flue is available in a choice of stainless steel or matt black powder-coated finishes, allowing you to select the option best suited to your installation.

The complete kit includes a flat appliance twin wall adaptor, two 1000mm straight flue lengths, a 500mm straight length, twin wall roof support, your choice of roof flashing, a storm collar, rain cap and 130–210mm wall support. The flue system is fully welded and insulated with high-density rockwool, providing continuous insulation throughout the system with no thermal bridges. It requires just 60mm clearance from combustible materials, making it a practical choice for a variety of single-storey stove installations.

Designed with installers in mind, the 5" Twin Wall Flue Kit offers quick and straightforward assembly and is supplied with locking bands for secure connections. The system is CE and HETAS approved and can be used for domestic heating and hot water systems, while also meeting biomass regulations. With a comprehensive selection of components included, durable construction and a 25-year warranty when installed by a competent person, this kit provides a dependable twin wall flue solution for extensions, garden rooms, outhouses and similar applications. Always confirm the suitability of the components with your HETAS-registered installer before installation.1x 37-125-005(BL)2-125-005(SS), 2x 37-125-010(BL)2-125-010(SS), 1x 37-125-011(BL), 1x 58-125-067(BL), 1x 58-125-182(BL), 1x 37-125-090(BL), 1x 58-125-053(BL)

Key Features

  • Complete 5" (125mm) twin wall flue kit for single-storey installations
  • Ideal for extensions, outhouses and garden sheds
  • 2 x 1000mm and 1 x 500mm twin wall straight lengths included
  • High-density rockwool insulation with continuous insulation throughout
  • Only 60mm clearance required from combustible materials
  • CE and HETAS approved for suitable applications
  • Stainless steel or matt black powder-coated finish options
  • Includes roof support, flashing, storm collar, rain cap and wall support
  • Supplied with locking bands for secure and straightforward installation
  • 25-year warranty when installed by a competent person
HETAS Approved
Warranty Lifetime

Dimensions & Specs

SKU
Single Storey Extension/Outhouse Flue Kit
Warranty
25 Year
Colour
Black, Stainless Steel
Product icon
Estimated 3-5 Day Delivery

Delivery Info

 Free Next Day or Day of Choice Delivery

Orders over £100 (to most UK mainland addresses) qualify for FREE delivery.
Place your order before midday (with in-stock items) for next working day delivery or choose a delivery date that suits you.
Orders under £100 are subject to a £6.95 delivery charge.
Deliveries are made Monday to Friday.
Weekend delivery (Saturday or Sunday) is available at an extra cost – contact us to arrange.

Click & Collect

Would you like your item faster? Use our Free Click & Collect service.
Available on in-stock items from our warehouses.
When placing your order, simply add a note stating your preferred collection date.
If you’re unsure about collection options, just get in touch, we’re here to help.

Delivery - What to Expect

Our standard deliveries arrive via a 10-tonne lorry (similar in size to a bin wagon or fire engine), equipped with a tail lift and pallet truck.
Access must be suitable: solid, level surfaces (no gravel, steps, steep slopes, or grass).
For palletised deliveries the driver will move the pallet to the nearest accessible point, but cannot go over unsuitable terrain or carry goods indoors, though may place them inside a garage if accessible.
If you have narrow gates, restricted access, or other challenges, please let us know in advance so we can make suitable arrangements.
Our free service is a one-man delivery. We recommend having someone available to assist, especially for larger items.
The delivery driver is not able to unpack or install your goods unless this is a service you have selected.

Checking Your Delivery

On delivery of your palletised goods, the driver will wait up to 10 minutes while you inspect the item(s).
Please check your goods before the driver leaves. If there is any damage or the driver refuses to wait, note this on the delivery slip (e.g., “Driver did not wait – damage unchecked”).
For any damage found, mark the delivery note clearly and contact us immediately.

Missed Deliveries

If you miss your pre-booked delivery, a re-delivery charge may apply.
For smaller items sent via courier (e.g., stove glass), the courier will leave a note with redelivery instructions if you’re not home.

Additional Delivery Notes

Accessory items like fitting kits and liner packs may be sent separately via courier on the same day. You’ll receive email confirmation if this is the case.
Delivery times are generally between 9am–6pm, Monday to Friday.
Delivery depots may send SMS updates, but these aren’t guaranteed.

Please DO NOT book installers, plumbers, electricians or other contractors until your goods have been delivered and checked, as delays can sometimes occur beyond our control.

Frequently Asked Questions

How much does delivery cost?

Most of our items come with free standard delivery to mainland UK when you spend over £100, but some larger or more remote deliveries may incur additional charges. You can view your delivery cost by entering your postcode at checkout before completing your order.

Do you deliver to all parts of the UK?

Yes, we deliver across the entire UK, including the Scottish Highlands and Islands, Northern Ireland, and other offshore locations. To check the exact delivery cost to your address, simply enter your postcode at checkout.

Is Click & Collect available?

Yes! We offer Click & Collect on a wide range of our products. Simply call our customer service team to check if your chosen item is eligible. Once your order is ready, we'll notify you with full collection details, including opening hours and what to bring with you.

Do you deliver to the Republic of Ireland (ROI)?

Yes, we do deliver to the Republic of Ireland. Simply select Ireland as your delivery country at the checkout to view shipping options and charges. Please note that delivery times may vary depending on the item, especially for larger or heavier products like stoves and fireplaces.

When will my order be delivered?

We offer a range of delivery options, including next day delivery on many of our products when ordered before the cut-off time. Delivery times for larger or made-to-order items may vary, each product page displays estimated delivery times to give you a good idea of when to expect your goods.

FAQs (1)

Customer Questions
Hi, thank you for your enquiry. Yes, this twin wall flue kit comes with locking bands to connect each piece of flue pipe together.
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Single Storey Extension/Outhouse Flue Kit - 5" Twinwall Flue (125mm)

Pay in instalments from 6 to 36 months

0% for 4 months or 6-36 months instalments.

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