Our Chimney was in bad repair, and we had two chimney companies come and and say basically the same thing, it needed to be partially torn down, re-bricked, new crown, new damper door. Ok, so the company we went with was out working on it today. When I saw the result of the partially done job it gave me concern, the bricks seem to have excess space between the bricks.

Upon inspection, the new bricks are a half 1/2 inch shorter than the previous bricks. The morter between the bricks is an inch wide though, is this a sign of bad masonry?

Notice the newer bricks near the top

3 Answers 3


Typical mortar joints are 3/8", but there is no rule for it, that it has to be that size. They can be much wider than that. I have seen joints as wide as you have pictured, no big deal, it is a matter of aesthetics. The mason could have looked to find the right size brick, but he may had to order them and possibly pay a premimum for them, especially if he is buying less than a cube(about 500 brick) much tougher when buying only a 100 or just a few dozen, so perhaps he went with what he could get.

The brick he is using may be 7 5/8" long, which is a "modular". The original brick may be 8" long or "standard" brick, from what I found on the internet. There is no way for me to know, it is an educated guess.

  • I don't think the wide mortar joint hurt and they don't look bad aesthetically. More importantly, they match the existing bricks rather well. Overall, looks good.
    – BrianK
    Sep 1, 2015 at 20:16

hmm chimney repair is expensive and 8 inch brick are not really hard to find. Visual aesthetic is a important factor for masonry and restoration, and proper brick bond is important in load distribution and tensil strength and ultimately waterproofing.. so 3/8 inch is the standard brick joint for all those reasons.


Depending on the local conditions, there may be a water proofing issue. Cementitious products (concrete and cement mortar) shrink due to the hydration process of cement. So your mortar joint will become slightly contracted. Clay bricks expand when they are moist and contract when they dry out. So the wider the joints are, the more the differential between mortar and brick becomes.

On a small length of wall (like the chimney) this should not be an issue, but I would be concerned if the builder built an entire wall like this.

I would not accept this, since it is an aesthetic issue. Anything that does not look "right" or "proper" will negatively affect the re-sale value of the house. So if you intend to sell, have it look nice. The next owner will probably not be too happy the way it looks.

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