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Care for historic chimney

My husband and I have been restoring a family home built in 1918. It had been sold out of the family and we have recently bought it back. There is a chimney in the middle sitting room that was painted with glossy black paint by previous owner. We have removed the paint and the bricks look great in their natural condition. We seem to have a lot of mortar dust (not sure if that is the proper term). My husband thinks we need to seal it with a brick sealant. However, I have read that historic brick is not good when sealed because it needs to not have moisture trapped within the brick. Any suggestions on how to care for this beautiful original part of our home? It is not a working chimney- used to be connected to a wood burning stove. Now we just have a flue cover over the hole. Maybe eventually we will connect something to it- but for now, I just love the original brick. Any advice would be appreciated.

Re: Care for historic chimney

The problem most likely started when it was painted due to moisture being t****d behind the paint.
The dust is the old Lime mortar falling out.
Contact a mason that knows about repairing the mortar joints in old Historic buildings.
In the early 1800's the mortar whould have been a Quick Lime mortar.
You MUST use a matching mortar.
Any high content Portland cement or Mortar mix will cause more damage to the brick.
You should have the existing mortar tested for it's make-up.
Contact one of these company. U.S.Heritsge Group, Inc.
Virginia Lime works.
Cathedral Stone
Also ask who they know in your area that works on Historical buildings.
Also include the U.S. Parks Services in your area for masons who work on old buildings.

Re: Care for historic chimney

Many thanks to you Clarence- your knowledge of this is excyclopedic and you just answered a question I was about to PM you with.

I just started some renovations to a 1930's house and saw where previous pointing and repair work was done with what seems to be a hard gray Portland-based mortar because it's causing the soft bricks to flake and crack. The original soft beige mortar seems to be Lime based and needs a little work here and there. The homeowner just asked me last night how we could determine what is was so he can make things right. Now I know the answer too!


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