How to Repoint Mortar on the Surface of a Retaining Wall

I am certainly no repointing or masonry expert, but after a bit of research and my own experience, I am sharing what I learned from the process.

What is Repointing?

Repointing is the process of renewing the pointing, the external part of mortar joints in masonry construction. Over time, freezing and thawing cause cracks in the joints between bricks, allowing water to seep in.

Choosing the Correct Mortar To Use for Repointing

Before you begin a repointing project, it is very important to determine the type of mortar needed for your project. Typically homes built before 1920 used lime based mortar and homes built after 1920 used a cement based mortar. If your home uses lime mortar, you cannot use cement mortar…this can cause irreparable damage to a home. Lime mortars should be replaced with lime mortars and cement mortar with cement. If you are not sure what type of mortar you have, take a small sample of your mortar and have it analyzed.

Water Damage Caused by Cracked Mortar

Water seeping into bricks can cause severe damage to a home, my advice is to repair the mortar in the early stages of cracking. I say that as a lesson learned from our front walkway project HERE, the mortar had become so badly damaged, the entire walkway was in need of repair.

Repointing the Mortar on a Retaining Wall

In our backyard, we have a very large retaining wall, separating the lower and upper level of the yard. Our yard allows us to walk out onto a flat surface from the main level and from the basement level.

During our patio replacement project HERE, we repaired the crumbling mortar between the bricks on the surface of our retaining wall.

Due to the height of the retaining wall, a safety railing was placed on the surface but overtime, the mortar joints have disintegrated where the railing is held in place.

Removing Old Mortar with a Chisel and Hammer

The first step in repairing the joints, is to dig out the old mortar. This can be done with a hammer and chisel HERE and HERE or an electric tool can be used.

Removing the old mortar takes time and patience.

Use a Brush to Clean the Surface of the Brick

Once the old mortar is removed, a brush is used to clean the debris and remove any loose mortar left behind. Mortar will bond better to a clean surface.

Proper Time of Year for Repointing

It is important to plan this job ahead of time, on a clear day without rain in the forecast. Repoint only when temperatures are between 40 and 90 degrees Fahrenheit. Cold makes mortar brittle, while heat dries it out and prevents hardening.

Tools Needed for Repointing

A pointed trowel HERE is used to insert new cement in the joint, working the mortar into the crevice carefully.

After the mortar has set, about one to three hours, a steel brush HERE is used to remove excess mortar from the surface of the brick, being careful not to touch the newly repointed joints.

Washing the Surface After Repointing

Approximately one week later, you can use a muriatic acid and water solution to wash over the face of the brick to remove any residual haze from the mortar.

How to Ensure Repointing Lasts a Long Time

Inspect the brick often for signs of moisture, and remove any plant growth as close to the surface as possible.

With proper maintenance, newly repointed mortar can last 25 – 50 years!

Have you done any DIY repointing? Any tips you can offer?

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