How To Repoint a Brick Foundation

Repointing a brick foundation can prevent water infiltration and structural damage to your home. This involves removing deteriorated mortar from the joints between bricks and replacing it with fresh mortar. In this article, we’ll explore the step-by-step process of repointing a brick foundation, guided by This Old House general contractor, Tom Silva.

Understanding the Need for Repointing a Brick Foundation

Brick foundations can last for decades, but over time, the mortar between bricks can deteriorate due to factors including weather exposure, water damage, and natural settling. When this happens, you must address the issue promptly to prevent more damage. Regular inspection and timely repairs can keep your home’s foundation safe against bigger problems.

Signs Your Foundation Needs Repointing

Crumbling or missing mortar between bricks, visible cracks in the mortar joints, water seepage in the basement, or loose and shifting bricks are a few indications suggesting your foundation needs repointing.

Benefits of Repointing

Repointing your brick foundation offers many advantages, including better structural integrity and an increased lifespan. Repointing also improves the appearance of your home’s exterior and prevents water infiltration.

Preparing for the Brick Repointing Process

Proper preparation is required for successful repointing. Having the right tools and materials and setting up a safe work area will make the process smoother and quicker.

Essential Tools and Materials

Having all your tools and materials ready will help with safety and efficiency during your project. Before starting your repointing project, get the following tools and materials:

• Brick chisel
• Dust mask
• Masonry hammer
• Masonry jointer
• Mortar mix
• Pointed trowel
• Raking bar
• Safety glasses
• Shovel
• Tuck pointer
• Wheelbarrow
• Work gloves

Setting Up the Work Area

To set up your work area, spread a drop cloth at the base of the brick wall to catch any debris. Make sure you are in a well-ventilated area while you work. Remember to wear safety gear, including glasses, a dust mask, and work gloves.

The Repointing Process

Repointing a brick foundation involves many steps for a durable and effective repair. Silva’s demonstration provides insight into the different techniques for this task.

Removing Old Mortar

Removing deteriorated mortar is the first step in the repointing process. Clearing the old mortar will prepare the brick joints for a strong bond with the new mortar. Follow these steps to remove old mortar without damaging the bricks:

1. Use a pointed raking bar to remove mortar from the horizontal bed joints between rows of bricks. Remove mortar to a depth of about 1 inch.
2. For vertical head joints, use a brick chisel and masonry hammer. Carefully tap out the mortar to a depth of one inch without damaging the surrounding bricks.
3. Use the chisel to remove any loose mortar or dust from the joints.

Preparing the Joints

Proper preparation helps the new mortar adhere well to form a consistent bond. Once the old mortar is removed, the joints must be cleaned and prepared for new mortar:

1. Inspect the cleaned-out joints for any remaining loose material.
2. Remove any cracked or damaged bricks that need replacement.
3. Use a garden hose to lightly wet the repair area and the raked-out joints. This prevents the dry bricks from drawing moisture out of the new mortar too quickly.

Mixing the Mortar

Mixing the mortar correctly will give you the right consistency and strength for a smooth application process. Follow these steps:

1. In a wheelbarrow, mix one bag of mortar mix with water according to the manufacturer’s instructions.
2. Use a shovel or hoe to combine the ingredients until you have a consistent texture.
3. The mortar should be stiff enough to hold its shape when squeezed but moist enough to be workable.

Applying New Mortar

Applying new mortar requires precision and attention to detail. Here’s how to do it:

1. Scoop some mortar onto a small square of plywood to use as a mortar board.
2. Use a narrow tuck pointer to pack mortar tightly into the vertical joints between bricks.
3. For horizontal joints, use a masonry jointer to force mortar into the spaces between rows of bricks.
4. Work in small sections until each joint is completely filled with new mortar.

Finishing the Joints

After applying the new mortar, finish the joints to give them a neat and uniform look. Follow these steps:

1. Once all joints have been filled, allow the mortar to set slightly.
2. Use the masonry jointer to strike off excess mortar and smooth the surface of the joints.
3. Aim for a consistent appearance across all repointed areas.

Addressing Any Issues During the Process

During the repointing process, you might encounter unexpected issues. Addressing these issues quickly will make the repointing process go much smoother. If the mortar dries too fast, lightly mist the joints with water to slow down the drying process. 

If bricks shift out of place, immediately realign them before the mortar sets. If the mortar becomes too thick or too runny, adjust the water content accordingly while mixing.

Replacing Damaged Foundation Bricks

In some cases, you may need to replace damaged or cracked bricks as part of the repointing process.

Removing the Damaged Brick

Removing any damaged bricks will make space for replacement. To carefully remove a damaged brick, use a chisel and hammer. Then, clean out all the old mortar from the surrounding area.

Installing the New Brick

Once the damaged brick is removed, install a new brick by applying a thick setting bed of mortar to the brick below. Spread mortar on the ends and top of the replacement brick. Slide the brick into place, checking that it aligns with the adjacent bricks. Tap the brick gently to set it and get a proper alignment.

Brick Repointing Curing and Aftercare

Proper curing is necessary for the longevity of your repointing work. Aftercare precautions will help the new mortar set correctly to maintain its strength.

Curing Process

Proper curing conditions help the mortar achieve its full strength and durability. Allow the mortar to dry slowly over several days. Mist the repointed areas lightly with water twice daily for the first three days to prevent rapid drying. Protect the newly repointed areas from direct sunlight and strong winds during the curing process.

Maintenance Tips

Regular maintenance will extend the life of your repointing work. Inspect your foundation annually for signs of deterioration, addressing any new cracks or loose mortar as you notice them. Keep gutters and downspouts clear to prevent water from pooling near the foundation. Consistent maintenance will help to identify and fix potential issues before they become bigger problems.

Common Repointing Mistakes to Avoid on Your Brick Foundation

When repointing a brick foundation, being aware of common mistakes can help you avoid errors. Using mortar that is too hard can damage the bricks, and failing to remove enough old mortar can affect durability. Do not apply mortar in poor weather conditions, and follow the steps to cure the new mortar properly.

Additional Tips for a Successful Repointing Project

Consider these additional tips for a successful repointing project: Avoid repointing during very hot or cold weather, as it can affect the mortar’s setting process. Always mix the mortar thoroughly for a uniform consistency throughout your project. Lastly, take the time to clean out the old mortar to provide a better bonding surface for the new mortar. With these tips and following our guide, you can get a professional-looking result.