Despite the overall structural stability of a building, environmental factors can still cause micro-movements that jeopardize the structure over time. That’s why architects and contractors include expansion joints during the design phase—to combat building movement. But how exactly do expansion joints prevent shifting? Let’s explore the basics of the expansion joint, and how they can be incorporated into to your next project.
Exploring the Basics of the Expansion Joint
Buildings are under constant stress from micro-movement. Expansion joints—the flexible gaps between the structural elements of your building—aim to relieve that stress by absorbing expansion and contraction within the structure. They separate slabs and concrete from other structural pieces, allowing for independent movement between neighboring components.
Buildings can move and sway for several reasons, including:
- Expansions and contractions due to temperature changes
- Wind sway
- Seismic activity
- Static/live load deflection
Of these, thermal expansions and contractions rank among the largest contributors to building movement. For example, when a building heats up, the materials within expand. Before the advent of the expansion joint, concrete plates and slabs would crack as weather changed. These cracks allow water into the structure—which, in time, jeopardize the building’s integrity.
By contrast, an expansion joint will contract and absorb the pressure to prevent materials from rubbing against each other and cracking. Additionally, expansion joints absorb movements to the upper part of a building when reacting to ground vibrations. This prevents deformations and protects the entire structure.
Expansion joints bisect your entire structure, marking gaps through the building components. This includes plazas or split-slab concourses, walls, decks, and foundations. Look at any building or large structure. If they’re not covered for aesthetic purposes, you can likely see expansion joints in vertical and lateral applications. That said, these gaps are usually filled and sealed to ensure the building is water-, sound-, fire-, and air-proof.
Considerations and Common Challenges in Expansion Joint Design
There are a few considerations when designing expansion joints. One must account for:
- Building Movement. In the planning phase, consider how vertical, horizontal, and shear movements generate tensile and compressive forces. Building shear is among the most restrictive values to consider during the design phase, as it’s usually the culprit of most structural damage.
- Empty Space. Architects and builders must incorporate empty space into designs to allow for the natural expansion and contraction of materials.
- Waterproofing Needs. Water damage is every structure’s worst enemy. When choosing an expansion joint, consider your waterproofing needs and how particular joints will maintain the building’s integrity.
An important extra consideration: vertical expansion joints—especially on masonry facades—are prone to failure first.
Expansion joints can withstand a beating; however, they aren’t invincible. Inadequate design, poor sealant installation, and improper mobility decrease their longevity. Regular maintenance and restoration are vital to ensuring the longevity of your building. Additionally, accounting for the following common problems can further inform the design of your construction project.
As mentioned, water leakage and ingress are among the most common problems you may experience. When there are cracks or holes in the joints—or if they expand enough to create space—water will find its way in.
Visible cracks and water damage indicate that your expansion joints may require maintenance. For example, in masonry facades, most expansion joints are caulked. But caulk doesn’t last forever; as UV light from the sun erodes it, water may sneak into the joint.
Expansion joints are also meant to absorb building movement due to temperature changes. But if improperly installed, they won’t insulate concrete components properly.
Additionally, sound and seismic waves can further jeopardize a building’s integrity due to improper installation or expansion joint failure. On bridges or in parking garages, expansion joints are also under constant stress from traffic.
Why do Expansion Joints Need Restoration?
Expansion joints are your first line of defense. That’s why routine maintenance and restoration are crucial from a safety and cost standpoint. Ignoring the problem will only lead to more substantial—and expensive—issues down the line.
If you notice cracking, pooling water, or weeds growing through your expansion joints, address the issue immediately. It’s easy to remove water and weeds, but cracks require trained industry experts. Working with professionals ensures that the job gets done safely and correctly.
Simply ignoring the problem is the worst thing you can do. Ensure that cracked expansion joints are repaired the moment you notice them. If you catch it early, you may only need to repair faulty joints. If you wait, you may need to remove and replace them entirely.
Keep Your Buildings Safe with Kent Companies
Buildings move; there’s little you can do about it. But what you can do is ensure your expansion joints are properly installed and in working order. When issues arise, it’s crucial that you call restoration experts like Kent Companies to address your expansion joints and prevent further structural damage.
Get in touch with Kent Companies if you’ve noticed wear and tear on your structure’s expansion joints.