Is It Called Grout Between Bricks in Masonry Structures?

The Core Difference: Mortar vs Grout in Brick Construction

In traditional brick masonry, the material that bonds bricks together is mortar. Mortar is a durable, slightly flexible mixture of cement, lime, and sand that fills the vertical and horizontal joints and provides adhesion. Grout, by contrast, is a denser cementitious mix designed to fill narrow gaps and voids with less shrinkage and more rigidity. This fundamental distinction matters for performance, water resistance, and maintenance. Understanding the difference helps homeowners avoid using the wrong product in projects that involve brick and masonry, which can lead to cracking, moisture intrusion, or weakened structural performance. Grout is sometimes used in specialized masonry tasks, such as grout-filled cores in certain brick units or grouted veneers, but these applications require careful planning and professional guidance.

When Grout Finds Its Place in Brickwork

While mortar is the standard for bonding bricks, grout has its place in certain conditions. Grout may be used to fill hollow brick cores for increased stability in reinforced masonry, or to fill large voids where a tight seal is needed, such as behind wall cavities or in repairs where a dense filler is required. In some decorative applications, grout is used to create solid-looking brick surfaces by filling the gaps between bricks in a veneer with a grout that matches the brick color. However, this is not typical for structural walls and should be approached with caution, as grout can introduce moisture-trapping issues if not properly designed and cured. Always check local building codes and consult a structural professional for grout-filled brickwork.

Visual Clues: How to tell grout from mortar in existing walls

Mortar joints are usually visible as uneven lines where bricks meet, and they often appear rougher and more textured. The color of mortar tends to drift slightly over time due to weathering. Grout joints, in contrast, are typically smoother, denser, and may be colored to match or contrast with the brick face; they also squeeze into narrower spaces and may penetrate into brick cores if used for reinforcement. A quick DIY check is to inspect a joint: if you scrape gently and a loose sandy texture appears, you might be looking at mortar; if the joint resists chipping and feels compact, it could be grout or a grout repair. But avoid removing material without a plan, as you could damage the brick or compromise the system.

Common DIY Scenarios: What homeowners run into

Homeowners often encounter damaged brick joints due to weathering, moisture, or settling. In most cases, repointing with fresh mortar is the proper fix; using grout to seal brick joints is generally not recommended for exterior walls because grout can trap moisture and cause deterioration. For interior or decorative projects, grout might be used behind bricks in a veneer or for non-structural applications when designed for that purpose. Before you begin, identify whether you are dealing with a structural joint or a cosmetic veneer, and choose the appropriate material accordingly. Always test a small area first and follow safety guidelines when removing old material and mixing new compounds.

Step by Step: Replacing damaged joints between bricks

1. Assess the joint and determine whether mortar joint repair is appropriate; 2) Remove damaged mortar to a uniform depth with a chisel and hammer, cleaning dust and debris; 3) Dampen the joint to reduce suction; 4) Mix fresh mortar to the correct consistency and trowel into the joint using a pointing trowel; 5) Tool the joint to achieve the desired profile; 6) Allow curing time and protect from moisture during early curing. If you are considering grout for this joint, consult a professional to ensure the grout's compressive strength and curing requirements align with the brickwork. This process should preserve the brick's appearance and structural integrity.

Tools, Materials, and Safety for Brick Joint Work

Essential tools include a cold chisel, hammer, margin trowel, pointing trowel, jointing tool, and a stiff brush for cleaning. Choose the right mortar mix (standard Portland cement-based mortar with lime) for exterior brickwork, and a grout mix only if the application truly requires grout for void filling or core reinforcement. Safety matters: wear eye protection, gloves, and a dust mask when removing old material, and ensure adequate ventilation when mixing cementitious blends. Read product labels and local building codes before starting.

Maintenance and Long-Term Care for Brick Joints

Regular cleaning to remove dirt and moss helps prevent moisture retention and deterioration. For exterior bricks, use non-acidic cleaners and avoid power washing at high pressure, which can erode joints. Inspect joints annually for cracks, spalling, or efflorescence, and address issues promptly to prevent water intrusion. Sealing brick surfaces should be done with caution, since improper sealing could trap moisture. If you notice significant cracking or movement, contact a masonry professional.

Cost Considerations and When to Hire a Pro

Costs vary based on the scope of the project, brick type, and local labor rates. In most cases, major mortar repointing or structural brickwork should be handled by a skilled mason. For small cosmetic veneer projects or repairs that do not involve structural joints, a competent DIYer with proper safety equipment can complete the job. Always obtain multiple estimates and check references before hiring.

Real-World Examples and Quick Fixes

Two common scenarios encountered by homeowners include bridging a cracked brick joint in a decorative brick wall and sealing gaps around a leaky exterior brick veneer. In such cases, a quick fix can involve removing damaged material and applying fresh mortar or appropriate grout where specified by the manufacturer. Always prepare the work area, protect adjacent surfaces, and cure properly according to product guidelines.