OT - Has anybody repointed bricks? any knowledge about lime mortar?

[mrrhtuner]

Just curious, has anybody repointed bricks before...more specifically with lime mortar?

Thank you

 

[imo000]

No, never.

 

[mjhandy]

We need our chimney done. Was told by a mason that repointed is a temp fix, but then he was looking for a contract.

Have you thought about digging out the old morter and just re-appling new stuff?

 

[mrrhtuner]

MJHandy and the rest of you tuning in.

As with anything, there is a quite a bit of science between mortar and bricks.

The key with bricks and mortar is that the mortar has to be softer then the brick. If you repoint an old house with portland cement/mortar, you risk ruining the brick faces after a period of time as the older bricks rely on the soft mortar for them to expand and contrast.


I found one contact in all of ontario, thanks to a large limestone production facility. I'll be heading out to the GTA tomorrow in the afternoon to pickup 2 bags of Type S Hydrated Lime.

To properly fix a wall, it's best to tear down the old brick and mortar and install more updated stone and portland cement.

Here is an interesting link:

http://easementsatlanta.org/2014/07...n-csi-lintels-and-masonry-mortar-part-2-of-3/

http://easementsatlanta.org/wordpress/wp-content/uploads/2014/07/Nspall2.jpg

"Example of improper repointing and surface grouting with portland cement causing historic brick spall due to different compressive strengths."


So with all that being said and done, to do a proper job you need the proper stuff for the brick to look good, weather properly and move as it needs to.


If you need your chimney done, as do I, they need to take down a few feet of brick and replace it with newer bricks. With that being done, portland cement is fine to use.

If they are just repointing your old brick with portland cement...it's a quick repair that you will need to redo in a few years time.

 

[Johhny04]

MJHandy and the rest of you tuning in.

As with anything, there is a quite a bit of science between mortar and bricks.

The key with bricks and mortar is that the mortar has to be softer then the brick. If you repoint an old house with portland cement/mortar, you risk ruining the brick faces after a period of time as the older bricks rely on the soft mortar for them to expand and contrast.


I found one contact in all of ontario, thanks to a large limestone production facility. I'll be heading out to the GTA tomorrow in the afternoon to pickup 2 bags of Type S Hydrated Lime.

To properly fix a wall, it's best to tear down the old brick and mortar and install more updated stone and portland cement.

Here is an interesting link:

http://easementsatlanta.org/2014/07...n-csi-lintels-and-masonry-mortar-part-2-of-3/

http://easementsatlanta.org/wordpress/wp-content/uploads/2014/07/Nspall2.jpg

"Example of improper repointing and surface grouting with portland cement causing historic brick spall due to different compressive strengths."


So with all that being said and done, to do a proper job you need the proper stuff for the brick to look good, weather properly and move as it needs to.


If you need your chimney done, as do I, they need to take down a few feet of brick and replace it with newer bricks. With that being done, portland cement is fine to use.

If they are just repointing your old brick with portland cement...it's a quick repair that you will need to redo in a few years time.

Could you share where this is located?

 

[mrrhtuner]

Could you share where this is located?

I made the drive out today to purchase 2 50lb bags of NHL 3.5 lime.

Graymont referred me to Skycon building products in the GTA.

http://skycon.ca/sky/index.php

 

[VW-DUBBED]

Hello mrrhtuner,
I do have a good knowledge for using lime mortar; quick question, are you going to use the chimney? if it's just decorative purposes, e.g. no fire nhl 3.5 would be fine. However, you would require 5 nhl lime mortar. This is great website to about the strength types of hydraulic lime mortar.

 

[Johhny04]

I made the drive out today to purchase 2 50lb bags of NHL 3.5 lime.

Graymont referred me to Skycon building products in the GTA.

http://skycon.ca/sky/index.php

Thanks for sharing. I'm going to have to fix my chimney soon too. Let us know how the job turns out with the products your bought. Good Luck.

 

[mrrhtuner]

Hello mrrhtuner,
I do have a good knowledge for using lime mortar; quick question, are you going to use the chimney? if it's just decorative purposes, e.g. no fire nhl 3.5 would be fine. However, you would require 5 nhl lime mortar. This is great website to about the strength types of hydraulic lime mortar.

Hey VW-dubbed...no I'm repointing a few sections of my rear and side exterior walls.

I do need the Chimney re-bricked, but I suspect they will use new bricks and can use regular portland cement.

Thanks for sharing. I'm going to have to fix my chimney soon too. Let us know how the job turns out with the products your bought. Good Luck.

Here, some clarity for anybody else looking into this with an older home:

NHL 2 - NHL 2 is softer and slow setting,
Feebly Hydraulic
Soft, Permeable Masonry
Minimal Exposure

NHL 3.5 - NHL 3.5 is for general building, suitable for moderately permeable masonry materials. Basically, if you don't need to use NHL 2 or NHL 5 then use this.
Moderately Hydraulic
Medium Density Masonry
Moderate Exposure

NHL 5 - NHL 5 is stronger and faster setting, more suitable for dense, durable or impermeable materials with severe exposure to weather or water.
Eminently Hydraulic
Dense, Impermeable Masonry
Severe Exposure


For Chimney you would want NHL 5:

NHL 5, Typical Uses:
Granite, engineering brick, basalt, flint, paving, roofing, chimneys, parapets, cornice, balustrades, copings, plinths, bridges, harbours, marinas, canals, dams, sea-fronts


http://www.lime-mortars.co.uk/articles/hydraulic-lime-which-nhl

 

[James & Son]

Yes i tried it as an exterior parge because of its plasticity, i thought it would not crack. The white resulting finish looked great. The only problem was a portion was not protected from direct rain and the colour became mottled from the moisture.

The key to any hydraulic lime or cement work in thin layers is humidity. The more humidity the better.

Absorption is the other.
Use a pressure washer to clean and drive moisture into the wall in advance of the work. Work on the shaded side of the structure and cover from the sun and wind