Repointing cement bricks

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Ameds
Posts: 19
Joined: Wed Oct 12, 2016 8:55 am

Repointing cement bricks

Post by Ameds » Fri Feb 01, 2019 7:30 am

Hello,

I have a "modern" 2010 fully bricked bungalow. I noticed a few areas in the mortar joints have cracked and need to be repointed in the spring.

When calling around for estimates, a young lad told me that what I have are new popular cement block/brick siding that is not the traditional clay based brick. He continued to tell me that this is an inferior product and only gained popularity because of the versatility of the color and shape it can offer.

He also said that the industry hasn’t really figured out how to repoint cement blocks correctly because they do not behave like your traditional clay brick. The cement does not absorb water like a brick does and contracts/expands as different rates.
Can anyone confirm this assertions and whether any specific considerations must be made to repoint cement block siding?

Clarence
Posts: 172
Joined: Mon Mar 27, 2017 9:15 am

Re: Repointing cement bricks

Post by Clarence » Fri Feb 01, 2019 7:45 am

The young lad is very close to what your problem is. The Mortar joints should be softer than the brick.
If the bricks were laid using the wrong mortar it would cause the joints to crack also could cause the brick to crack. If you plan on repointing the joints the existing joints need to be cut back 1&1/2 inches in depth for a correct repoint plus the correct mortar most be used. Say if the weakest brick is 5000 PSI your mortar should not exceed say about 2000 PSI most bricks are laid using a type N mortar which is 750 PSI.

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