Twin Wall flue through the roof with offset- black (1 or 2 story house)

This twin wall insulated flue system has been designed for a single or double storey straight flue, that runs through the inside of the house terminating through the roof.

Click on the product in the "your selections" box to get the details of the chosen product.
Once you add this list to the shopping basket, you can make changes like adding or deleting products.

twin wall through the house

twin wall flue

1Diameter of flue liner:

WOODSTOVES & MULTIFUEL STOVES: The flue legally needs to be a minimum of 6" (150mm) in diameter if you are burning wood or coal. Unless when you install a DEFRA approved stove with a 5" flue outlet, in which case you can use a 5" liner (125mm).

What diameter of flue liner do you need?
125 150
The ideal flue size is typically determined by the exhaust outlet of the stove or appliance. It shouldn't to be smaller than the appliance exhaust hole.

The Building Regulations (Document J, page 30) require that the minimum flue size for stoves are as follows:
- Up to 20kW burning smokeless fuel - minimum 5" - 125mm diameter.
- Up to 30kW burning any fuel - minimum 6" - 150mm diameter.
So the regulations recommend a minimum flue size of 150mm for any stove (on which wood could be burnt) unless it is Defra Exempt.

OPEN FIRES including flame effect open gas fires:
Minimum 200mm diameter for fire openings up to 500mm x 500mm. Larger fires require a flue area equal to 14-16% of the total area of the fireplace opening. (Minimum flue diameter 180mm for gas effect fires).
2Choose the adapter between stove and twin wall flue
Many wood-burning stoves come with the choice of attaching the flue pipe to either a top or rear flue exit. All things being equal, it’s best for a flue pipe to go up in a straight line in order to achieve the best draw and most efficient burn from your woodburner.

For the adaptor you have the following options:

- Single to twin wall adapter (also increasing adapters)

To be pushed into the stove opening; sits inside the spigot of your stove and then connect to other twin wall flue pipe above. Or push into the stove pipe.

-

- Single to twin wall continental adapter

A continental twin wall adapter creates the easy connection of Twin walled flue pipe to any European model of stove.

This Continental Stove Adapter is to use if you have a European stove collar; as the sizes are slightly smaller than a standard 5" or 6" stove collar.

5" continental adapter: outside of the adapter is 115mm; to twin wall 125mm (5"), and

6" continental adapter: outside of the adapter is 135mm; to twin wall 150mm (6").
What kind of adapter between your stove and the twin wall flue?
Standard adapter 5" to 5 +£0.00 Standard Adapter 6" to 6 +£0.00 Increasing adapter 4" to 5 +£0.00 Increasing adapter 5" to 6 +£0.00 Continental adaptor +£0.00
3What is needed to go though the ceiling?

Passage of a flue through the floor

The passage through a flammable floor can be done with:

- a Ventilated Firestop plate against the ceiling (in practice customers often take a round trim plate for the first ceiling); and
- a Vented Floor support on the floor.

How many floors to pass through?
None (Flue goes straight up through the roof) +£0.00 One Story house +£0.00 Two story house +£0.00

Passage of a flue through the floor

The passage through the floor can be done with:

- a Ventilated Firestop plate against the ceiling (in practice customers often take a round trim plate); and
- a Vented Floor support on the floor.

1. Put a length through a pre-prepared wood box in the floor and slide down the Vented Floor support plate.

2. Screw this Floor support plate to the box. Next, screw the support clamp directly to the jacket pipe of the length.

3 Glue the Ventilated Fire Stop plate (or round trim plate) onto the ceiling
4What elements are needed for the required offset

Introduce an offset in your flue (see picture)

Determine how many mm the flue should move sidewards.
To create the offset we can work with elbows of 15°, 30° or 45°. A lower angle is better for the draw.

Wall brackets

Both elbows need to supported by a bracket. These brackets can be a roof support, a wall support or floor support.

Attention: You need to check if the required offset comes with an upward length that fits under your roof. If it does not; you need to find a solution, most likely go for a smaller offset...

What offset is required?
30mm sidewards (upwards 240mm) +£0.00 80mm sidewards (upwards 280mm) +£0.00 80mm sidewards (upwards 430mm) +£0.00 130mm sidewards (upwards 310mm) +£0.00 150mm sidewards (upwards 670mm) +£0.00 170mm sidewards (upwards 450mm) +£0.00 260mm sidewards (upwards 450mm) +£0.00 280mm sidewards (upwards 1150mm) +£0.00 300mm sidewards (upwards 670mm) +£0.00 440mm sidewards (upwards 630mm) +£0.00 550mm sidewards (upwards 1110mm) +£0.00 800mm sidewards (upwards 980mm) +£0.00
5Determine how many straight pipes need to be used

We need to calculate how many straight elements we need going upwards; knowing that we already added some length to the flue through the adapter and the offset.

Step 1 : calculate how high the flue should be on the roof

To determine the required height on the roof (G) see " Complete information" below.

Step 2: Calculate the total height of the flue (stove to cowl)

Total height of the flue = B+C+D+E+F+G. (In case of a 1 storey house; D, E and/or F can be 0)

Check: The total height from stove to end cap should be at least 3.5 meter (building regulation recommends 4.5 meter).

Step 3: Determine how much length is in your shopping cart already

In your cart is already:

- the length from the offset - Question 4

Step 4: Calculate the length that has to come from the straight pipes

Total height of the flue - what is in your cart allready.

Note: a bit higher is okay, but do not take a lower height.

What height is needed from the straight elements?
Straight length: 1,9m +£0.00 Straight length: 2,3m +£0.00 Straight length: 2,8m +£0.00 Straight length: 3.3m +£0.00 Straight length: 3,8m +£0.00 Straight length: 4.2m +£0.00 Straight length: 4,7m +£0.00 Straight length: 5,3m +£0.00 Straight length: 5,6m +£0.00 Straight length: 6,1m +£0.00 Straight length: 6,6m +£0.00 Straight length: 7,5m +£0.00 Straight length: 8,5m +£0.00 Straight length: 9,4m +£0.00

Chimney Heights and Termination

A simple rules

Within 600mm from the ridge
The flue has to end minimum 600mm above the ridge.

More than 600mm from the ridge
The distance between the cowl of the flue and the adjacent roof/wall/structure should be higher than 2.3 mtr.

For the height on the roof this means:

Pitch of the roof Height on the roof.

25° 1070mm

30° 1330mm

35° 1610mm

40° 1930mm

45° 2300mm

50° 2740mm

All the rules

The minimum chimney height recommended for minimum performance of wood burning and multi fuel appliances is 4.5 m from the top of the appliance to the top of the chimney. In practice you 3.5m is often enough.

The distance between the cowl of the flue and the adjacent roof/wall/structure should be higher than 2.3 mtr.

Within 600mm from the ridge: Flue has to end minimum 600mm above the ridge.

The diagram below, taken from Document J (building regulations), shows the minimum flue discharge heights and positions for all wood burning and multi fuel applications.

In some cases, particularly when chimneys are towards the bottom of a sloping roof or at the eaves, it may be necessary to increase the chimney height above these minimum mandatory requirements. The reason for this is to clear pressure zones created by wind hitting the roof and nearby structures, like trees, which may interfere with the up draught required by the appliance or fire.

The maximum freestanding stack height above the roof for a traditional masonry chimney is 4.5 times the narrowest horizontal part of the chimney.
In the case of stainless steel system chimneys, the manufacturer’s installation instructions should be consulted; however in most cases it will be around 3 metres. This measurement is taken from the last point where the chimney stack passes the through or past the edge of the roof up to the chimney capping or termination. Tall chimneys may need bracing, always consult the manufacturer for advice.

For buildings with flammable roofs such as felted, thatched, or shingle roofs the flue or chimney the regulations are different. The flue or chimney must terminate at a minimum1800mm above the combustible surface.
6What kind of roof, and what is the pitch of the roof?

The choice of the flashing depends upon:

- What kind of material material is covering the roof, and

- The pitch of the roof (0° being a flat roof, 60° a sharp roof)

Automatically we ad a roof support and -when required- a storm collar.

What is the pitch of the roof and what flashing do you need?
Normal house tiles: Lead flashing 0 -25°(Stainless Steel) +£0.00 Normal house tiles: Lead flashing 25 - 45° (Black) +£0.00 Flatter tiles and slates: Aluminium - rubber flashing (0 - 45° maximum) +£0.00 Metal roof, non tiles roofs: EPDM flashing (0 - 45° maximum) +£0.00
7Do you need a finishing plate?

A finishing plate can be used to cover the opening between the flue and the ceiling under the roof.

Do you need a finishing plate?
No finishing plate needed +£0.00 Finishing plate 0 - 30º 2 parts +£0.00 Finishing plate 30-45º 2 parts +£0.00 Round trim plate +£0.00
8What kind of Cap is required?

There are 2 types of cap to choose from:

Rain cap
Will keep vertical falling rain out of the flue. In case of side winds, rain will enter the flue. In case of a flue outside this is less of a problem, as it will not floote into the house.

All weather Cowl
Keeps rain out of the flue. Also blocks downwinds from entering your flue. Downwinds come from higher objects in the vicinity (up to 10mtr), and without this Cowl they will blow the smoke back into your house.

What kind of Cap is required?
Rain cap +£0.00 All Weather Cowl +£0.00
9Do you need to support a free standing length of more than 1.5m?

You need to support the flue over the roof if the free end becomes higher than 1.5m.

We recommend to use a Roof Stabiliser Bracket, if the free end is between 1,5m and 3m.

The bracket comes with two telescopic legs that extend from 1m-2m in length. Also a band which secures around the flue and connects to the legs.

Do you need to support a free standing length of more than 1.5m?
No support needed +£0.00 For a freestanding flue of 1.5 - 3m +£0.00

Reset Wizard

Flue kits are based on general assumptions of the typical dimensions of houses and bungalows. You may need to add or take out certain items which can be done in the shopping cart. Other items can also be added to cart as necessary in the general Twin wall flue section. Flue-pipes.com does not take responsibility for the items installed in your flue system as this is merely a guide. Please check the twin wall flue pack is appropriate for your requirements. Refer to HETAS regulations and building regulations for further clarification.

Your Selections

Total amount: £0.00

Incl. Tax Excl. Shipping

Your Selections

0 items

Total amount: £0.00

Incl. Tax Excl. Shipping

Twin Wall flue through the roof with offset- black (1 or 2 story house)

1Diameter of flue liner:

What diameter of flue liner do you need?

2Choose the adapter between stove and twin wall flue

What kind of adapter between your stove and the twin wall flue?

3What is needed to go though the ceiling?

Passage of a flue through the floor

How many floors to pass through?

4What elements are needed for the required offset

What offset is required?

5Determine how many straight pipes need to be used

What height is needed from the straight elements?

6What kind of roof, and what is the pitch of the roof?

What is the pitch of the roof and what flashing do you need?

7Do you need a finishing plate?

Do you need a finishing plate?

8What kind of Cap is required?

What kind of Cap is required?

9Do you need to support a free standing length of more than 1.5m?

Do you need to support a free standing length of more than 1.5m?

Your Selections

Your Selections

What other people are saying about us:

About us

Our services

Flue pipes

Pitch of the roof	Height on the roof.
25°	1070mm
30°	1330mm
35°	1610mm
40°	1930mm
45°	2300mm
50°	2740mm

Twin Wall flue through the roof with offset- black (1 or 2 story house)

1Diameter of flue liner:

What diameter of flue liner do you need?

2Choose the adapter between stove and twin wall flue

What kind of adapter between your stove and the twin wall flue?

3What is needed to go though the ceiling?

Passage of a flue through the floor

How many floors to pass through?

Passage of a flue through the floor

4What elements are needed for the required offset

What offset is required?

5Determine how many straight pipes need to be used

What height is needed from the straight elements?

Chimney Heights and Termination

A simple rules

All the rules

6What kind of roof, and what is the pitch of the roof?

What is the pitch of the roof and what flashing do you need?

7Do you need a finishing plate?

Do you need a finishing plate?

8What kind of Cap is required?

What kind of Cap is required?

9Do you need to support a free standing length of more than 1.5m?

Do you need to support a free standing length of more than 1.5m?

Your Selections

Your Selections

What other people are saying about us:

About us

Our services

Flue pipes