DM36 - 360mm square x 250mm high access casing
At a Glance
- Constructed from natural pumice for superior insulation
- Double-wall design reduces thermal stress and prevents leaks
- HETAS approved and CE marked for industry-leading safety standards
- Versatile design suitable for stoves, open fires, and cookers (wood, oil, solid fuel, gas)
- Features a 150mm internal diameter access hole for easy inspection and maintenance

Please Note: All dimensions refer to the internal diameter of flues. If unsure, please call 01670 206999 to ensure you choose the correct products.
We Won't Be Beaten On Price
At National Flues, we continuously monitor competitor prices. This ensures that we consistently offer you the best deals on all our products. Here’s how we keep your costs low:
- Daily Price Matching: Our team adjusts prices to ensure we stay competitive.
- Bulk Purchasing Power: We sell a lot, so we can negotiate better rates with suppliers, passing the savings directly to you.
- Operational Efficiency: We have streamlined processes to reduce overhead.
Price Match Guarantee: If you find the same product cheaper within 48 hours, we’ll match it and refund the difference.
Free Delivery Over £100: Orders over £100 are free delivery (call us if delivery is required outside the mainland UK).
“I saved 20% on my purchase compared to other retailers. Exceptional service!” – Jane D.
Have Questions?
Phone: 01670 206999
Email: [email protected]
- Info
- Specs
- Install
- FAQs
The DM36 360mm square x 250mm high access casing is part of the Isokern Double Module (DM) block system, renowned for its exceptional thermal insulation and durability. Constructed from natural pumice, this casing maintains optimal flue gas temperatures while preventing heat transference to the outer casing. The unique double-wall structure allows for thermal movement, minimising the risk of cracks and leaks.
Quick and easy to install, the DM36 is suitable for a wide range of heating appliances including stoves, open fires, and cookers using wood, solid fuel, oil, or gas (excluding condensing appliances like Biomass and Pellets). Approved by HETAS and CE marked, the Isokern DM system ensures superior performance and safety, keeping your chimney warmer for longer and reducing condensation and soot build-up.
SKU: 59-130712
Technical Specifications | |
---|---|
Dimensions | 360mm square x 250mm high |
Internal Access Hole | 150mm diameter |
Material | Natural Pumice |
Certification | HETAS Approved, CE marked |
Warranty | 10 Years |
Suitable For | Stoves, open fires, cookers (wood, oil, solid fuel, gas; excluding condensing appliances) |
Design | Double-wall for enhanced thermal performance |
Delivery Information +
We work relentlessly to ensure you get your order fast. Estimated delivery for this product is Friday, April 4th. If you need faster stove or fireplace delivery please give us a call. We can often reduce longer lead times if we pay the carrier £25 for express delivery. Visit our Shipping Information page for more information.
Warranty & Returns +
All our products come with warranties. Mi-Flex offers a lifetime guarantee. Returns for damaged items are covered by insurance; non-damaged returns incur return delivery costs.
Price Match Guarantee +
We will match any price like for like. If you find it cheaper within 48 hours, we'll refund the difference.
Compatible and other products that may be of interest...
National Flues Ltd Verdict
The DM36 access casing is a top-tier product, perfect for various heating appliances. With Nationwide delivery and services to both retail and trade customers, National Flues ensures quality and reliability in every purchase.
The DM36 access casing is designed to maintain optimal flue gas temperatures and prevent heat loss in chimneys, enhancing the performance and safety of heating appliances.
National Flues is a leading supplier of fireplaces and flues in the UK, offering unbeatable prices, reliable delivery, and excellent customer service to both retail and trade customers nationwide.
