How to Repair Your Cracked Brick Wall: Step-by-Step Guide

Brick walls are known for their durability and timeless appeal, but they're not immune to damage. Whether you're dealing with hairline cracks, crumbling mortar, or more serious structural issues, knowing how to repair brick wall damage is an essential skill for homeowners.

Why Do Brick Walls Crack?

Understanding the root cause of brick wall damage is crucial before attempting any repairs. By identifying what's causing the cracks, you can address the underlying issue and prevent future damage.

Foundation Settling

One of the most common causes of brick wall cracks is foundation settlement. As your home's foundation shifts and settles over time, it can create stress on the brick structure above. This often results in diagonal cracks that start at the corners of windows or doors and extend upward.

Weather Changes

Brick is porous and absorbs moisture. When water freezes inside these tiny pores during winter, it expands and can cause the brick to crack or spall (when the face of the brick pops off). Repeated freeze/thaw cycles accelerate this deterioration, making weather one of the leading causes of brick damage in colder climates.

Construction Works in Your Area

Nearby construction, especially heavy excavation or demolition, can create vibrations that affect your home's structure. These vibrations can cause existing small cracks to widen or create new ones in your brick walls.

Aging Mortar Joints

Mortar typically has a shorter lifespan than brick. Over time, mortar joints deteriorate due to weather exposure, causing them to crack, crumble, or recede. This weakens the wall's overall structure and can lead to loose or displaced bricks.

Is It Necessary to Repair Cracks in Brick Walls?

Not all cracks require immediate attention, but most should be addressed eventually. Small, cosmetic cracks may seem harmless but can allow moisture to penetrate the wall, leading to more significant damage over time. Structural cracks, which are typically wider than 1/4 inch and change in width, indicate potential structural issues and should be repaired promptly.

While a crack in your brick wall does not always lead to weather or structural damage immediately, it does affect your home's aesthetic appeal and can develop into more serious problems if left unaddressed.

Repairing brick wall damage not only restores your home's appearance but also prevents water infiltration, which can lead to mold, interior damage, and compromised structural integrity. For extensive damage or if you're uncertain about the severity, consulting with a professional who specializes in brick masonry services is recommended.

Tools and Materials You'll Need

Before starting your brick wall repair project, gather all necessary tools and materials. Having everything ready will make the process smoother and more efficient.

Tools:

• Masonry hammer or chisel

• Wire brush

• Pointing trowel

• Masonry jointer

• Bucket for mixing mortar

• Safety glasses

• Dust mask

• Gloves

• Spray bottle with water

• Angle grinder (for larger repairs)

Materials:

• Mortar mix (Type N for most residential applications)

• Replacement bricks (matching existing ones)

• Masonry sealer (optional)

• Epoxy repair system (for small cracks)

• Tarp or plastic sheeting (to protect surrounding areas)

• Clean water for mixing

Pro Tip: When selecting replacement bricks, bring a sample of your existing brick to a local brickyard for the best match in color, size, and texture. For mortar, try to match the color of existing mortar for a seamless repair.

Step-by-Step Guide to Repair Cracks in Your Brick Walls

Follow these detailed steps to effectively repair your damaged brick wall. Take your time with each step to ensure a durable and visually appealing result.

Step 1: Inspect the Damage

You'll need: Tape measure or ruler, camera, notepad. 

Time: 15–30 minutes.

Begin by thoroughly assessing the extent and type of damage. Look for patterns in the cracks that might indicate the underlying cause. Horizontal cracks often suggest foundation issues, while vertical cracks may result from thermal expansion. Stair-step cracks (following the mortar joints in a stair pattern) typically indicate foundation settlement. 

Measure the width of cracks and note whether they appear to be growing.

Step 2: Clean the Area

You'll need: masonry hammer/chisel, raking bar or grout saw, wire brush, spray bottle.

Time: 30–60 minutes for a small area.

Proper preparation is crucial for a successful repair. Remove any loose or damaged mortar and brick pieces using a chisel and hammer. Work carefully to avoid damaging intact bricks. For mortar joints, use a raking bar or grout saw to remove damaged mortar to a depth of about 3/4 inch.

Once loose material is removed, use a wire brush to clean out dust and debris. Finish by spraying the area with water to prevent the dry brick from absorbing too much moisture from the new mortar, which would weaken the bond.

Step 3: Mix the Mortar or Epoxy

You'll need: mortar mix or epoxy kit, bucket, mixing paddle, water, gloves, respirator.

Time: 10–20 minutes to mix.

For mortar repairs, follow the manufacturer's instructions to mix the mortar to an oatmeal like consistency. It should be malleable but not too wet. If you're using an epoxy repair system for small cracks, prepare it according to the product instructions.

Always wear a dust mask when mixing dry mortar to avoid inhaling harmful silica dust. Mix in a well-ventilated area and consider using a HEPA vacuum for dust control when cutting or grinding mortar.

Step 4: Apply the Repair Material

You'll need: pointing trowel, mortar, jointer. 

Time: Varies. 

For mortar joint repairs (repointing), use a pointing trowel to press new mortar firmly into the cleaned joints. Fill the joints completely, working in layers for deeper repairs. Avoid smearing mortar onto the face of the bricks.

For small cracks in the brick itself, use the epoxy repair system, carefully following the manufacturer's application instructions. For larger repairs involving multiple bricks, apply a bed of mortar, then position the replacement brick, tapping it gently into place with the handle of your trowel.

Step 5: Replace Damaged Bricks (If Needed)

You'll need: chisel/angle grinder (rented), replacement brick, mortar, trowel. 

Time: 30–90 minutes per brick depending on complexity.

If you need to replace entire bricks, carefully remove the damaged brick after cutting out the surrounding mortar. Clean the opening thoroughly and dampen it slightly. Apply mortar to the bottom and sides of the opening, then press the replacement brick into position.

Ensure the new brick is aligned with the surrounding bricks and maintain consistent joint widths. Remove excess mortar immediately and fill any remaining gaps with additional mortar.

Step 6: Allow to Cure

You'll need: Water spray, protective covering for weather. 

Time: Initial tooling 30–60 minute

After applying mortar, allow it to set until it's firm but not completely dry (usually 30-60 minutes, depending on weather conditions). Then use a jointer tool to shape and compress the mortar joints to match the profile of existing joints.

Once tooled, allow the mortar to cure for at least 24 hours, misting it occasionally with water to prevent it from drying too quickly, which can cause cracking. Protect the repair from direct sunlight, wind, and rain during this curing period.

Step 7: Seal and Protect

You'll need: breathable masonry sealer (optional), brush/sprayer. 

Time: 1–2 hours to apply after mortar has cured.

After the mortar has fully cured (typically 7-10 days), you may want to apply a breathable masonry sealer to protect against moisture infiltration. Choose a sealer specifically designed for brick that allows the wall to "breathe" while repelling water.

Apply the sealer according to the manufacturer's instructions, typically using a brush, roller, or sprayer. Be careful not to over-apply, as this can trap moisture within the wall and cause further damage.

When to Call Professionals

While many brick wall repairs can be handled as DIY projects, some situations call for professional expertise. Consider consulting with specialists in local brick repair or chimney repair in these scenarios:

• Structural cracks wider than 1/4 inch

• Cracks that continue to grow despite repairs

• Bulging or leaning walls

• Extensive damage covering large areas

• Water damage behind the brick wall

• Historic buildings requiring specialized restoration techniques

• Foundation-related issues

Professional masons have specialized tools, materials, and expertise to handle complex repairs safely and effectively. They can also identify underlying issues that might not be apparent to the untrained eye.

What to Avoid When Repairing Brick Wall Cracks

Avoid these common mistakes that can lead to failed repairs or additional damage:

• Using the wrong type of mortar (modern Portland cement on historic brick)

• Applying non-breathable sealers that trap moisture

• Ignoring the underlying cause of cracks

• Rushing the curing process

• Attempting structural repairs without proper knowledge

• Using interior patching compounds on exterior brick

Common Questions Answered

Quick, scannable answers to the most common homeowner questions about repairing brick walls.

Q: When can I DIY and when should I call a pro?

A: DIY for simple repointing and small hairline cracks, call a professional for structural cracks (wider than ~1/4 inch), bulging or ongoing movement. See the "When to Call Professionals" section for guidance.

Q: Will sealing the wall prevent all water issues?

A: No, sealing can help, but only if you use a breathable masonry sealer and first fix drainage or moisture sources. Non-breathable sealers can trap moisture and worsen damage.

Q: What tools should I buy and what should I rent?

A: Buy hand tools and safety gear (trowel, jointer, wire brush, safety glasses, respirator). Rent heavy equipment like an angle grinder or scaffolding for larger jobs to save cost and storage space.

Final Thoughts

Repairing brick wall damage is a manageable DIY project for many homeowners, especially when addressing minor cracks and mortar deterioration. By understanding the causes of damage and following proper repair techniques, you can restore both the appearance and structural integrity of your brick walls.

Remember that prevention is the best approach to brick wall maintenance. Regular inspections and addressing small issues promptly can save you from more extensive repairs down the road.