Expansion joints in blockwork allow walls to move naturally without cracking under pressure. Without them, shifts caused by temperature changes, moisture, or settling can lead to structural damage. Proper placement by a professional bricklaying service company ensures stability and longevity, preventing unsightly gaps or costly repairs.
This post covers the purpose of expansion joints, how thermal movement impacts block walls, and common installation errors to avoid.
What Are Expansion Joints and Why Are They Needed?
Expansion joints are deliberate gaps in blockwork that allow movement without causing damage. Blocks expand and contract with temperature changes, moisture levels, and structural shifts. Without these gaps, pressure builds up, leading to cracks, buckling, or displacement.
Correctly placed joints prevent structural failure by absorbing movement across large wall sections. Spacing depends on factors like material type, exposure, and wall dimensions. Poor positioning or incorrect sealing can render them ineffective, creating weak points instead of protection.
Building codes specify placement to control stress and prevent unsightly damage. Sealants or compressible fillers keep gaps functional while maintaining weather resistance. Ignoring them risks costly repairs and compromised integrity over time.
Find out the right way of storing blocks by reading our blog here.
How Temperature Changes Affect Block Walls
Temperature changes affect block walls by causing expansion in heat and contraction in cold conditions. Movement occurs as materials respond to daily and seasonal shifts. Without proper allowances, stress builds, leading to cracks or displacement.
Thermal expansion increases pressure along rigid sections, especially in longer walls. Expansion joints relieve this stress by creating controlled gaps for movement. Without them, materials push against each other, weakening the structure over time.
Incorrect spacing or missing joints can result in bowing, stepped cracks, or failure at mortar joints. Proper design accounts for environmental conditions to prevent long-term issues. Well-placed joints keep surfaces stable while maintaining strength and durability.
Common Mistakes When Installing Expansion Joints
The common mistakes when installing expansion joints are incorrect spacing, poor sealing, misalignment, and filling gaps with rigid material:
- Incorrect spacing: Gaps placed too far apart fail to relieve movement stress. Cracks form when pressure builds beyond the wall’s tolerance.
- Poor sealing: Using the wrong sealant or skipping this step allows moisture to seep in. Water penetration weakens mortar and accelerates deterioration.
- Misalignment with control joints: Expansion gaps must align with control joints to function correctly. Misplaced cuts leave rigid sections vulnerable to cracking.
- Filling gaps with rigid material: Hard fillers prevent movement instead of absorbing it. Blocks push against each other, causing buckling over time.
