Twin Wall Flue - External -Stainless steel -offset

Many wood-burning stoves come with the choice of attaching the flue pipe to either a top or rear flue exit. From the stove, you can lead the chimney directly outside, run it upwards first and then outside, or take the chimney all the way through the house.

For the adaptor you have the following options:

Single to twin wall adaptor (also increasing adaptors)

This adaptor can be installed in two ways:

1. Direct connection – push the adaptor into the stove opening so it sits inside the spigot of your stove. From there, connect the twin wall flue pipe above.
2. Connection via stove pipe – install a length of single wall stove pipe first, then push the adaptor into the top of the stove pipe and continue upwards with twin wall flue pipe.

Single to twin wall continental adaptor

A continental twin wall adaptor creates an easy connection of twin wall flue pipe to any European model of stove.

This Continental Stove Adaptor is used if you have a European stove collar, as the sizes are slightly smaller than a standard 5" or 6" stove collar.

• 5" continental adaptor: outside of the adaptor is 115 mm; to twin wall 125 mm (5")
• 6" continental adaptor: outside of the adaptor is 135 mm; to twin wall 150 mm (6")

The distance can be calculated as:  distance = G + E + D

G = distance heart of stove outlet - to- wall
E = thickness wall
D = distance outside wall - to - flue  (usually 50mm, but can go up to 350mm in case you want to go along a overhanging roof, without using elbows)

If the distance is fixed (you can not move the stove forward or backward) you will most likely need an adjustable T135 piece. When you have some flexibility in the distance between stove and wall; you can do with a - cheaper - simple T135 piece.

Together with the T135 piece, we will add:
- the 45 degree elbow
- the wall sleeve. The wall sleeve is meant to slide through the wall and to be cut to length as required. Add mortar around outside of it or fireproof insulation.
- 2 finishing plates, to cover the opening between the flue and the wall; both inside and outside.

In case of an overhanging roof you need to create an offset (or go straight up at a longer distance from the wall)

Introduce an offset in your flue (see picture)

Determine how far the flue should jump forward (stay away at least 10mm from the gutter)

Normally the wall brackets used along the wall, give the flue a 50mm distance from the wall. So an offset of e.g. 79mm means that the distance between wall and flue becomes 129cm.
For a good draw, it is best to use two 30º bends. Both bends must be secured with a wall bracket. The top wall bracket is best placed just below the gutter.

In this step we add 2 x 30° Elbow, an extra long wall support bracket, plus - when required- a straight element.

We need this to calculate how many straight elements we need to add.

1 Determine what the total height (S) of the flue should be

Determine the required height on the roof (M)  see " Complete information" below.

Now we know the total required height of the Flue (S) = M + L - K
L = Height of the roof
K = Height of the stove

2 Determine the height you have already in the shopping cart

Part of this height is coming from parts already in your shopping cart:

R = Height coming from the Diagonal section going outwards (take from question 3)
P = Height coming  from the Offset (take from question 4)

3 Calculate how much height has to come from straight elements

Height straight parts = S - P - R

Check: The total height (S) from stove to end cap should be at least 4.5m according to building regulations. (minimum 3.5m) 

You do not need to have the exact height, a little bit more is also okay (and cheaper than taking an adjustable length)

You need a base support unit to that carries the weight of the outside flue. (A wall support only gives sidewards stability)

You can choose between:

- Base Support Bracket : Can carry the weight of maximum 5 m of flue

- Base Support: Can carry the weight of up to 12m of flue

Type of Wall support 

Normally the wall supports with a 50 - 70mm distance wall - flue are taken.

With the offset, we already added an extra-long wall support for the upper 30° elbow. Here we add another 50 - 70mm wall support for the lower 30° Elbow.

Number of Wall supports

This depends on how many meters the flue goes along the wall.
We recommend to use a wall support  every 3 meter along the wall.  So every 2 - 3 meter above the T45 piece; 1 wall support.

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.

You need to support the flue over the roof if the free end becomes too long and requires additional support. We recommend to use a telescopic support if the free end is between 1,5m and 3m.