If you’ve ever parked in a multi-storey car park and noticed those narrow gaps in the floor or along the walls, you’ve probably come across an expansion joint. They might not look like much, but they’re doing an important job — keeping the whole structure safe and sound. This article breaks down exactly what expansion joints are, why they matter in car parks, what types are usually used during refurbishments, and why getting the installation right is absolutely crucial.
What Exactly Are Expansion Joints?
An expansion joint is basically a gap between two parts of a building that allows it to move slightly without causing damage. In a car park, these gaps are filled with flexible material that can compress and expand depending on what’s happening around them.
Movement in buildings happens all the time. Think:
– Changes in temperature (hot summers, cold winters)
– The weight of vehicles driving and parking
– Slight shifts in the ground or concrete settling over time
Without somewhere for that movement to go, the structure would crack, let water in, or even start to break apart.
Multi-storey car parks go through a lot. You’ve got constant vehicle traffic, heavy loads, exposure to rain, frost, de-icing salts, and temperature swings from top decks to basement levels. All of that creates stress on the building materials.
If the concrete can’t move slightly to relieve that stress, it cracks. Cracks let in water. Water leads to rusted reinforcement. And that’s how major repair problems start.
Expansion joints help prevent that by giving the structure a bit of flexibility. They protect the building’s integrity, make it safer, and extend its lifespan.
Types of Expansion Joints Used in Refurbishment
When you’re refurbishing an older car park or upgrading its joint system, there are a few common types of expansion joints often used:
1. Compression Seal Joints
These are pre-compressed foam or rubber strips that expand into the joint gap. They’re great for sealing horizontal joints like floors and decks, and they’re pretty good at keeping water out.
2. Strip Seal Joints
These use a tough rubber insert held in place with metal rails. They’re durable and ideal for high-traffic areas, like ramps or entrance levels where movement and wear are significant.
3. Elastomeric Joints
Made from flexible rubber materials, these are designed to stretch and bend without cracking. They’re especially useful in areas that need a lot of flexibility.
4. Joint Covers
For refurbishments, we sometimes use cover systems that go over the existing joint to upgrade its performance and appearance. They help keep things neat and are often used when repairing or updating an older joint.
|
Type of Joint |
Description |
Best For |
|
Compression Seal |
Foam or rubber strips that expand into the gap to keep water out |
Decks and horizontal joints |
|
Strip Seal |
Rubber insert with metal rails; handles heavy traffic and movement |
Ramps, entrances, and busy levels |
|
Elastomeric |
Flexible rubber materials; stretch and bend with movement |
High movement areas |
|
Joint Covers |
Surface-mounted systems to update or repair old joints |
Refurbishments where appearance matters |
What Happens When Installation Goes Wrong?
If the installation is done poorly, it can cause all sorts of problems:
– Cracks forming around the joint
– Water leaks getting into lower levels
– Premature wear or joint failure
– Trip hazards for pedestrians
And once water starts getting into the structure, things go downhill fast. Steel inside the concrete starts to rust, concrete breaks away, and you’re looking at expensive repairs.
Expansion Joint Troubleshooting Guide
If you’re seeing issues in your car park and wondering if the expansion joints are to blame, here’s a handy guide to common symptoms and what they could mean:
|
Symptom |
Possible Cause |
What You Should Do |
|
Cracks forming near joints |
Movement not properly absorbed |
Assess joint size and type; consider upgrade |
|
Water leaking to lower levels |
Failed sealant or compromised waterproofing |
Replace joint seal with watertight option |
|
Rust stains or spalling concrete |
Water ingress causing rebar corrosion |
Inspect joint and nearby concrete areas |
|
Joint material looks worn or loose |
Ageing material or improper installation |
Schedule inspection and replace if needed |
|
Trip hazard or uneven surface |
Joint cover or infill has lifted |
Re-level or replace surface-mounted joint |
If you’re unsure, a professional inspection can save you time, money and a lot of hassle.
Getting It Right from the Start
Here’s a more detailed breakdown of what best practice looks like:
1. Start with a Full Assessment
Before any work begins, a thorough assessment of the existing conditions is essential. This includes:
– Measuring the joint widths at various locations
– Determining the level of expected thermal and structural movement
– Identifying signs of distress like cracking, spalling or water ingress
– Checking for compatibility with existing waterproofing and drainage systems
This step ensures that the joint solution you choose will perform correctly under real-world conditions. It also helps prioritise which joints need replacing or upgrading first.
2. Surface Preparation
Proper preparation of the concrete substrate is critical. No matter how good the joint system is, it won’t last if it’s bonded to a poorly prepared surface. Good prep work usually includes:
– Removing all old joint material and any contaminants (oils, dirt, loose concrete)
– Repairing adjacent surface damage
– Grinding or priming the substrate to improve adhesion
– Ensuring moisture levels are within acceptable limits before applying new materials
Skipping or rushing this step is a leading cause of joint failure.
3. Selecting the Appropriate Joint Type
The right joint depends on a variety of factors, including:
– Traffic load: Heavily used areas may require reinforced or heavy-duty joints
– Location: Rooftop decks may need enhanced waterproofing properties
– Movement range: Wide gaps or areas with high thermal variation need more flexible joints
– Exposure: Joints exposed to the elements must be UV-stable and resistant to chemicals like de-icing salts
A technical specification should be developed for each joint to ensure it meets both performance and durability standards.
4. Precision in Installation
Good installation practice includes:
– Accurate placement of the joint system in the designed position
– Applying adhesives or sealants in controlled conditions (temperature, humidity)
– Ensuring no air gaps or voids under pre-formed seals
– Using templates or spacers to keep joints level and flush with the surrounding surface
In multi-storey car parks, joints must often align with drainage details or integrate with deck waterproofing, so coordination is key.
5. Routine Inspections and Ongoing Maintenance
Once installed, expansion joints should be checked regularly. A basic maintenance routine includes:
– Clearing debris from surface joints
– Checking for signs of wear, shrinkage, or hardening of flexible materials
– Replacing sealants or worn components before they fail
Re-applying protective coatings where used
Well-maintained joints can last many years, but neglecting even small issues can lead to major structural problems.
Key Points to Remember
Expansion joints might not be the first thing you think about when it comes to car park design or maintenance, but they’re one of the most important features. They stop cracks, prevent water from getting in, and help your structure last longer.
If you’re managing or refurbishing a multi-storey car park, make sure expansion joints are on your radar. Get the right ones installed properly, and they’ll do their job quietly in the background, saving you time, stress, and money.
Need help with a joint refurbishment? Reach out to Vision Structural Consulting or get in touch at 01375 213119 for a free initial chat.
