Renovating chimney

[Monaco]

Is there anyone with knowledge in brick & plaster? I have a chimney in need of renovation. The chimney is built with old large brick with 4 flues. The partitions are also of large brick and are laid with the bricks on their narrow long side. The chimney is also plastered with modern plaster. The idea is to repair the chimney in the simplest and quickest way to withstand the winter.

The problems are:
- Partitions have come loose 2-3 rows down.
- The plaster is very bad and has come off a lot.
- The sheet metal around the chimney is finished.

How to fix the partitions in the best way?
- Which brick should I buy?
- Which mortar should I use?
- What should I prime with that will adhere to the old?
- Should the partitions be reinforced with any metal cross or similar since they are not bonded?

How to fix new plaster?
- Chicken wire or plaster mesh. How to attach it?
- Priming on the old?
- Which mortar?
- Any tips for working at a temperature of 5-10 degrees Celsius?

I would appreciate any answers.

 

[Claes Sörmland]

Buy large bricks in the same dimensions you have. The building supply store that sells to masons and stove builders has them or can order them. In my area, it's Optimera that has this in stock, but it surely varies between locations where the masons shop.

Use the same mortar as before. If it's an old chimney (before the 50s/60s) then hydraulic lime mortar is the way to go. Both for plastering and for masonry. It adheres well to brick and is easy to work with, a bit stickier than later cement-based mortars.

I don't think you need to reinforce the partitions.

Plaster with fiberglass mesh. Again, use hydraulic lime mortar if it's an older chimney. Otherwise, use regular plaster.

It's a bit late to plaster with lime mortar now since winter is so close. Lime mortar should ideally have time to carbonate over the summer before frost and rain come.

 

[Stefan N]

Is it just supposed to survive the winter and then be demolished? Forget the plaster, it will hold for one winter anyway.

 

[Monaco]

Buy large bricks in the same dimension as you have. The building supply store that sells to masons and stove makers has it or can order it. In my area, it's Optimera that has this in stock, but it certainly varies between places where masons shop.

Use the same mortar as before. If it is an old chimney (before the 50s/60s), it is hydraulic lime mortar that is used. Both as plaster and for bricklaying. It sticks well to bricks and is easy to lay bricks with, a bit more adhesive than later cement-based mortars.

I don't think you need to reinforce the partition walls.

Plaster with fiberglass mesh. Again hydraulic lime mortar if it is an older chimney. Otherwise, regular plaster.

It's a bit late to plaster with lime mortar now since winter is so close in time. The lime mortar should ideally have time to carbonate over the summer before frost and rain come.

154009"]Buy large bricks in the same dimension as you have. The building supply store that sells to masons and stove makers has it or can order it. In my area, it's Optimera that has this in stock, but it certainly varies between places where masons shop.

Use the same mortar as before. If it is an old chimney (before the 50s/60s), it is hydraulic lime mortar that is used. Both as plaster and for bricklaying. It sticks well to bricks and is easy to lay bricks with, a bit more adhesive than later cement-based mortars.

I don't think you need to reinforce the partition walls.

Plaster with fiberglass mesh. Again hydraulic lime mortar if it is an older chimney. Otherwise, regular plaster.

It's a bit late to plaster with lime mortar now since winter is so close in time. The lime mortar should ideally have time to carbonate over the summer before frost and rain come.[/QUOTE]

Buy large bricks in the same dimension as you have. The building supply store that sells to masons and stove makers has it or can order it. In my area, it's Optimera that has this in stock, but it certainly varies between places where masons shop.

Use the same mortar as before. If it is an old chimney (before the 50s/60s), it is hydraulic lime mortar that is used. Both as plaster and for bricklaying. It sticks well to bricks and is easy to lay bricks with, a bit more adhesive than later cement-based mortars.

I don't think you need to reinforce the partition walls.

Plaster with fiberglass mesh. Again hydraulic lime mortar if it is an older chimney. Otherwise, regular plaster.

It's a bit late to plaster with lime mortar now since winter is so close in time. The lime mortar should ideally have time to carbonate over the summer before frost and rain come.

Thanks for the response! I will probably go with more modern mortar then. The plan is to demolish the chimney in a few years and rebuild it.
The goal is to get it approved and sealed so it can be used for a winter or two.
What should I use as a base? The old stones are probably quite clogged with soot and algae, etc.