Renovate the old chimney stack

[elin83]

Have exposed the old chimney in the kitchen and want to keep the feeling. The chimney sweep says we need to repair the joint, but how and with what? The house was built in 1947. We fire daily in the chimney during winter.

 

[larsbj]

Have exposed the old chimney in the kitchen and want to keep the feeling. The chimney sweep says we need to repair the mortar, but how and with what? The house was built in 1947. We burn daily in the chimney during winter.

The best thing might be to plaster the whole surface.... as it was originally.
In any case, it is most likely some type of kc-bruk.
Buy a bag of plaster and mortar C and test it. It can vary in color.
Soak thoroughly before repointing

 

[elin83]

But do you need to chip out the joint first?

 

[larsbj]

But do you need to chisel out the grout first?

No, I wouldn't do that, just repair where needed.
Since it is probably the mortar from the masonry and not old grout that is visible, it is better to leave it untouched.

 

[elin83]

Thank you!

 

[elin83]

It crumbles a lot, how could we deal with it?

 

[Kowarts]

Mix boiled linseed oil and balsam turpentine in roughly equal parts and paint the chimney stack with it after you've filled in the joints.