Paul Whitehead, Sales Director for Isedio products at Leviat, looks at the five most important considerations for the specifier when it comes to concrete joints and how cracks can be controlled and minimised.
In a world of fast-track construction, the demands a concrete floor will encounter whilst occupied can be considerable. This is why the specification and installation of armoured joints are such critical considerations for commercial and industrial concrete floors.
For logistic centres and distribution warehouses, the integrity of concrete flooring has never been more important as any downtime will impact the bottom line for businesses, many of whom operate 24-7, 365 days a year. Floor joints have become a significant feature for Facility Managers, Structural Engineers and Flooring Contractors in these high traffic environments as they allow safe transfer of loads, and accommodate the natural shrinkage of concrete as it dries.
The scale of these buildings also continues to grow becoming larger and taller, resulting in higher loading demands on floor slabs. The selection of or positioning of the wrong joint products could result in costly repairs, once the building is in use.
As an example, a common joint armouring cost for a typical 50,000m² concrete floor, would make up approximately 2-2.5% of the overall floor slab cost which is minimal. However, not selecting the correct product from the outset can result in downtime later down the line, increasing costs overall. Imagine having one or two aisles out of action for health and safety reasons, due to joint and material handling equipment damage, for several weeks in a 24-7 operation. The loss of revenue due to downtime could be huge. This is why even small details can have significant consequences in these warehouse environments.
Given the critical nature of floor joints in these demanding environments, it’s essential to understand the key considerations that go into their specification and installation.
Key considerations:
- Correct product selection
Precise engineering and correct product selection is crucial and typically involves a collaborative effort between the Flooring Contractor, Structural Engineer, and Flooring Consultant. For larger projects, a Flooring Consultant is usually appointed. These experts consider various factors, including traffic patterns (i.e forklift type and wheel specification), racking and layout, the presence of automation and robotics, and all material handling equipment. Even the product finish of the armoured joint – whether mild steel, galvanised steel, or stainless steel – plays a role in the decision-making process. - Aspect ratio and panel size
While guidelines are not rigid, the optimal configuration for a slab panel is 1:1 or a maximum 1:1-1:5. Slab panels commonly range from around 25m x 25m or up to 40m x 40m maximum. It’s important to note that the larger the slab panel, the larger the joint opening. - Joint opening
It’s essential to minimise the joint opening of armoured joints because the larger the joint opening, the more opportunity you have for joint impact and damage. Additionally, even impact free joints can become ineffective if the joint opening is not controlled. Typically, a 10-15mm joint opening is common but all joints will have limitations on what they can achieve. - Joint positioning and third party restraints.
Concrete likes to shrink, move and crack, so positioning joints is important. When armoured joints are installed in locations where there are additional floor restraints to consider, this can restrict the joint opening, which could result in cracking. These aspects require careful consideration by both the Structural Engineer and Flooring Consultant. - Regulations and best practices
In the UK and parts of Europe, the industry relies on a document known as TR34-4th edition, Concrete Industrial Ground Floors – A guide to design and construction which is currently in its fourth edition. While not strictly mandatory, it serves as a best practice guide for achieving the best possible concrete floor. It is often the case that prestigious projects typically require adherence to TR34 standards.
The stakes are high for all parties involved. An e-commerce business might want their floor insured for 10-15 years or more, with assurances that it won’t fail. This cascades down the chain to Structural Engineers, Main Contractors, and Flooring Consultants, all of whom need substantial insurance coverage to protect against potential failures in these massive facilities.
By carefully considering these factors, specifiers can select the most appropriate armoured joints for their projects, potentially saving substantial costs in the long run by avoiding premature failures, excessive maintenance, or the need for early replacement. Choosing the right floor joint from the outset can futureproof a concrete floor and lead to significant savings over the life of the building.