How to Repair Brick Mortar Joints

What You'll Need
Pressure washer
Heavy wire Brush
Pointing trowel or fingers
Acid wash

Brick mortar joints typically last 30 to 40 years before they begin to go bad. It can happen sooner, though, if a low quality mortar was used or if the mortar joints are constantly exposed to bad weather conditions. This article will cover how to determine if your mortar joints are bad and how to repair them if they are.

Step 1: Inspect the Brickwork

Start by looking for large amounts of dirt and other grime. It may be hiding damage to the joints. Next inspect all of the individual mortar joints. Check for cracking, splitting and a change in the space between bricks. Then use a small screwdriver to test the stability of the mortar joints. If the mortar is soft or flakes, it needs to be replaced.

Step 2: Cleaning

You can hand scrub the brick and the mortar joints, but that takes a lot of time and effort. Consider renting a pressure washer instead. A pressure washer sprays a powerful jet of water that will quickly clean your brickwork.

Step 3: Remove the Bad Mortar

With either a chisel and hammer or a heavy wire brush, begin to get rid of the old mortar from the mortar joints. You can also use a grinder. Be careful to only brush away or chip out the bad mortar. Eventually, you will find the place underneath where the mortar is still hard and strong. Check every so often to make sure you do not accidentally get rid of this good mortar. It will be needed to create a strong, lasting bond with the new mortar.

For added assurance, you can apply a bonding agent to the now exposed joints. It will help create a stronger bond. Many hardware stores carry bonding agents.

Step 4: Buy Mortar Mix

The process of repairing mortar joints is also known as re-tucking or re-pointing. Sometimes, you can get a mortar mix that is made specifically for this task at a store that sells masonry supplies. If they don’t have it, buy the highest quality mix they sell. It is worth the extra expense to get the best materials. You want your new mortar joints to last a long time, and that won’t happen with a poor quality mortar mix.

Step 5: Spread Motar

Mix your mortar according to the directions on the bag. Put on a pair of work gloves and begin spreading the mortar into the mortar joints. You can use a professional tool called a pointing trowel, or you can use your fingers. If you decide to use your fingers, the following method works best: apply the mortar using your gloved hands and then run your finger along the joint to create an indentation that goes slightly lower than the brick’s edge. Make sure you match the depth and size of the new mortar joints to the old joints if there is any remaining.

Step 6: Let it Dry

Allow the new mortar joints to dry. Then, if there is any excess mortar on the bricks themselves, use an acid wash to clean it up. Follow the directions carefully and remember to always wear protective gear.