Gaps in brick stairs

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New Member
Dec 21, 2023
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new york
Hello all.
I have brick steps with what I think are called limestone treads. As you can see, there are gaps that have formed between the bricks. Can someone advise me on how to fill in this cracks as a temporary measure? I will work on the permanent fix later.

There are also gaps between the tread and the back riser which is made of brick; as you can see in the second pic.


For a temporary & inexpensive repair, you could blow the dust out, dampen the bricks and use Type N or O mortar to fill the gaps. Type N is soft enough to easily grind or chip out when you wish to do the permanent repairs. Type O will be really easy to get out of the joints later. Really Easy! (It won't last terribly long outside. Maybe a few years.)

Don't use Type S. It'll be much harder to grind out for permanent repairs later. It might be too hard for the limestone or bricks You want mortar that is softer than the bricks or limestone so that the mortar will crack before the brick or stone. Unless they are pre-late 1800's bricks, Type N is the one for the bricks. Sandstone, I don't know. My limestone sills are held with N.

The step with the crack in the tread would be more appropriately fixed with vinyl patching cement. It's too tiny for mortar to fit. It will leave a permanent stripe on the tread.

Keep in mind that you should get the excess mortar off of the limestone as soon as it is stiff enough to brush with a nylon brush. It locks into the limestone.


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