Correct termination height
We calculate the proper height above the roof edge alongside you. This keeps the draw stable and prevents smoke downdrafts.
External flue pipe along the facade
Published on 27 August 2026
Written by Dries Nijs3 min read
Written by Dries Nijs3 min read
External wall chimney in short
An external flue pipe along the facade costs 1,500 to 2,800 euros installed, making it ideal when your stove sits against an exterior wall. The external flue is always twin wall and terminates high above the roof.
Straight through the wall, then straight up: that is the external facade route in a nutshell.
An external flue pipe along the facade is the logical choice when your stove is placed against an exterior wall: expect to pay 1,500 to 2,800 euros fully installed. Keep in mind that the termination point must finish high above the roof, for new installations at least 1 meter above the ridge line. The external flue is always twin wall.
Below you can read when the facade is the right choice, which regulations apply, how installation works, and what each component costs.
When to choose the facade route
The best route depends on where your stove is placed and how your home is built.
Facade is ideal when
The stove stands against an exterior wall and the wall penetration is only 30 to 50 centimeters long.
There is no usable chimney stack and you do not want to bore through upper floors.
Installation must be completed in 1 workday, without major roof work.
Future modifications or relocating the stove must remain possible.
Better through the roof when
The stove is positioned centrally in the house, far from an exterior wall.
You want optimal draw: inside, the route goes straight up with 0 to 2 bends.
You prefer not to have a visible 6 to 8 meter pipe mounted on your exterior wall.
The roof is already being worked on during a renovation.
If you are doubting between both options, read our full guide on roof vs facade flues or check out how an internal flue through the roof works.
Running along the facade saves internal structural work, but the chimney outlet must still reach the same height as a roof penetration.
Sturdy, neat wall mounting
Our wall brackets are anchored securely into load bearing masonry at proper intervals. Your chimney stays straight against the wall, even in heavy winds.
Guidance on rules & regulations
We check safety clearances to windows, neighbours, and local rules with you. You will know in advance if any notification or permit is required.
Regulations: height, windows, and permits
For new installations in Flanders, VLAREM II regulations dictate that the termination point must extend at least 1 metre above the roof ridge, or above the highest point of buildings within a 50-metre radius. An external chimney system therefore runs up past the roofline, although existing installations are exempt.
As a rule of thumb, maintain a clearance of at least 1 metre from openable windows and air inlets: the NBN B 61-002 standard defines the exact clearance zones. Some local councils require planning notification for a visible flue on the front facade, though this is rarely necessary for rear external walls. For further background details, visit the Buildwise standards page.
How an external flue pipe is constructed
A correct installation follows 6 steps, moving from the inside out.
Create the wall penetration, leaving 50 to 80 millimetres of clearance from combustible materials.
Fit a 90-degree T-piece with a drain cap on the exterior wall as the base of the stack.
Build the twin-wall insulated flue vertically, featuring 25 to 30 millimetres of insulation.
Install wall brackets every 1.5 to 2 metres, along with a base support bracket directly above the T-piece.
Ensure the flue extends no more than 1.5 metres unsupported past the top bracket: add extended guy wires or bracing otherwise.
Finish with a rain cap, followed by a test burn and full certification.
To learn more about how this T-piece functions, read our guide to the T-piece with drain cap. We cover the wall pass-through itself in key considerations for wall penetrations.
Key points when mounting a flue on an external wall
Choose a drain cap that is easy to empty, especially when running a pellet stove.
Ensure the T-piece doubles as a sweeping hatch to keep annual chimney sweeping simple.
Match the finish: black or stainless steel, and check local guidelines for front-facing walls.
Consider your neighbours: keep the flue outlet away from nearby windows and ventilation shafts.
Verify the CE plate rating: look for a G-rating and T400 temperature class for wood and pellets.
Maintenance of an external flue system
An external flue requires low maintenance, but it cannot be ignored completely. Empty the drain cap 2 times per heating season, schedule an annual chimney sweep via the inspection T-piece (which typically costs 60 to 90 euros separately), and inspect the brackets and silicone sealant around the wall penetration every 2 years. Proper care allows a stainless steel external flue to easily last 25 to 30 years.
How much does an external flue pipe cost?
The following guide prices apply to a standard property requiring a 6 to 8 metre external flue run.
Component | Guide price |
|---|---|
T-piece with drain cap and wall plate | 100 to 180 euros |
Twin-wall insulated flue pipe | 80 to 120 euros per metre |
Wall brackets and fixings | 150 to 250 euros |
Fully installed and commissioned | 1,500 to 2,800 euros |
Self-assembly saves roughly 500 to 900 euros in labour fees, but wall penetrations and structural anchorage demand precision, and insurers require a fully compliant flue in the event of a claim. For complete peace of mind, let our specialist team install your external flue system. Read our detailed breakdown on what a complete new flue installation costs. Individual parts like T-pieces, brackets, and rain caps can also be found in our online shop.
Want to calculate the exact cost of an external flue for your property, including wall pass-through and secure anchoring? Request a free quote or tailored advice to receive a fixed price quote for your situation.
Looking to install or inspect an external facade flue?
We are happy to help. Contact us without obligation.
Related articles
Frequently asked questions
Just as high as a roof penetration: for new installations at least 1 meter above the roof ridge or above the highest point of structures within 50 meters. Additionally, maintain a rule of thumb of at least 4 meters total flue length to ensure a strong, natural draw.
As a rule of thumb, keep a clearance of at least 1 meter from openable windows and ventilation intakes, both your own and those of neighbours. Standard regulations specify exact clearance zones depending on your situation, which your installer verifies during measuring.
Yes, a single wall pipe cools down too quickly outdoors, leading to condensation, creosote buildup, and lost draft. A insulated twin wall flue with 25 to 30 millimeters of insulation keeps flue gases warm across the full 6 to 8 meter run.
Usually not, though some local councils require notification for a visible chimney pipe on a front facade. It is rarely required for side or rear walls. Checking with your local municipality beforehand takes just one phone call and prevents issues later on.
Expect to pay 1,500 to 2,800 euros for a fully fitted external flue of 6 to 8 meters. Materials cost 80 to 120 euros per meter plus 100 to 180 euros for the T-piece with drain cap. Self-installation saves 500 to 900 euros in labour.