Cracks in your brick walls or block foundations are warning signs that something’s wrong. To stop these cracks, it’s important to know the difference between expansion joints and control joints. Many homeowners ask, “Why is my wall cracking?” or “Could this have been avoided?” In most cases, the solution involves putting the right joints in the right locations when the wall was constructed. Doing this right helps keep your walls strong and looking good for years.
Protect your home with help from the best masonry contractor in Mobile, AL. Call today for expert service.
Phone: (251) 283-5661
Email: contact@mobilemasonryal.com
What Is an Expansion Joint?
It is like a built-in “gap” that allows masonry to safely expand and contract with the weather. As temperatures rise and fall, materials naturally expand and contract. These joints are filled with compressible materials like foam or rubber to absorb movement without causing stress on the structure.
Key Features:
✔ Absorb movement (expansion and contraction due to heat/cold)
✔ Prevent cracks in large structures like bridges, driveways, and multi-story buildings
✔ Wider than control joint (usually ½ inch to 1 inch)
✔ Filled with flexible sealant to allow movement
Where Are They Used?
- Long Brick Walls
- Block Walls (CMU walls)
- Retaining Walls
- Exterior Masonry Facades
- Veneer on Buildings
- Fireplaces and Chimney Stacks
What Is a Control Joint?
It is a line or groove that’s purposely placed in concrete to “control” where cracks happen. Unlike expansion joints, control joints do not allow movement; instead, they guide cracks to form in a straight, controlled line rather than randomly.
Key Features:
✔ Create intentional weak spots to direct cracking
✔ Thinner than expansion joint (usually ¼ inch deep)
✔ Common in concrete slabs and block walls
✔ Not filled with flexible material (often left as a groove or saw cut)
Where Are They Used?
- Reinforced Masonry Walls
- Concrete Block (CMU) Walls
- Brick and Block walls
- Interior floors
After the concrete is poured, these typically involve shallow cuts with a specialized tool to preserve the strength and appearance of your area.
Key Differences Between Expansion and Control Joints
Feature | Expansion Joint | Control Joint |
Purpose | Allows movement between masonry sections | Controls cracking from shrinkage |
Width | Typically ½” to 1″ wide | Typically ¼” or less |
Material | Filled with flexible sealant (like caulk or foam) | Often left unfilled or lightly tooled |
Movement | Absorbs expansion and contraction | Does not allow movement |
Which Joint Should You Use—And When?
Choosing between a joint type depends on the type of masonry, the size of the structure, and the environment. Here’s a quick guide to help you decide:
Use an Expansion Joint When:
✔ The masonry wall or structure is large or long.
✔ Temperature changes cause materials to expand and contract.
✔ There’s movement or vibration nearby (busy roads, machinery, or seismic activity)
Example: A long brick facade on a commercial building will need it every 20-30 feet to prevent cracking and damage.
Use a Control Joint When:
✔ The block wall or masonry is prone to shrinkage cracks as it dries and cures.
✔ You want to control where cracks appear, making them neat and less noticeable.
✔ It is a smaller or interior structure, such as partition walls or basement block walls.
Example: A block basement wall should have control joints placed every 15-20 feet to prevent random cracking.
Why Proper Joints Matter in Masonry
Ignoring joints can lead to:
🔴 Uncontrolled cracking (ugly, uneven breaks)
🔴 Structural damage (shifting walls, uneven surfaces)
🔴 Costly repairs (replacing entire sections instead of maintaining joints)
For maximum durability, a professional masonry contractor makes sure they are filled and positioned correctly.
Need Expert Masonry Services in Mobile, AL?
If you’re planning a new construction project or repairing existing masonry, proper joint installation is critical. Mobile Masonry Contractors provides high-quality, durable masonry solutions that fit your requirements.
📞 Call: (251) 283-5661
📧 Email: contact@mobilemasonryal.com
Frequently Asked Question(s)
Not every small job needs them, but for larger surfaces or areas that meet buildings, they are crucial.
Usually every 8 to 10 feet, but it depends on the size and thickness of your surface.
Flexible materials like rubber, foam, or bitumen strips are common and allow for movement.
Skipping can cost you more later. They prevent damage that often leads to expensive repairs.
Yes! Placement done incorrectly can do more harm than good. A skilled mason ensures correct spacing and materials.
