Chimney flue replacement

[ptlf]

How should I ensure a tight and durable fit when replacing this 150mm square asbestos cement duct with a 125mm spiral duct? Can I gently break the duct and insert the spiral into the wall and cement it in place, or should I use some kind of mortar? If so, do I need to mix in small pieces of brick to make it work well? I gladly welcome any tips

 

[ptlf]

No one?

 

[myrstack]

Check out this thread, the link might be broken now but search for stos or Inloppsrör and you'll find products you can use for the connection to the chimney.

When it comes to suitable mortar, read about the recommended thicknesses for an application. If you stay within the limits, there's no reason to fill up with pieces of brick or similar.

// Mats

 

[ptlf]

Thanks, I thought it might be better if the pipe goes all the way into the channel in the wall instead of an adapter on the outside, but maybe it doesn't matter.

 

[myrstack]

I would say it doesn't matter, but I would probably make it so that it's easy to separate everything from the chimneystack anyway. Sharp transitions from spiro to chimneys are difficult to clean if needed in the future.

// Mats

 

[ptlf]

Cement mortar or concrete? You can make cement thick and also some concrete, but which one adheres better and sets faster?:S