Have you ever thought that the warehouse floor slab might just be the most important part of your sophisticated new distribution centre? All other elements of the process are affected (for good or bad) by the quality and durability of the floor slab.
And as warehouses get bigger and taller, and the systems within them get more complex the need for flatter floors becomes critical. However, the floor is all too easily overlooked.
Tony Hulett of flooring specialists Face Consultants says: “We are concerned that the flooring condition is last on the list of priorities when it comes to the acquisition of new or old buildings.
“Historically, we have often been asked to investigate flooring difficulties after the transaction on a building has been settled and the company has moved in, where soon afterwards, things start to go wrong with their floor. Fortunately, things seem to be changing and we are discovering that more companies are taking a proactive interest before sealing their commitments. Perhaps it is a case of once bitten – twice shy,” he says.
“Before consenting to full repairing leases, prospective tenants need to undertake a detailed survey of the floor. Considerations should include the structural integrity – will it take the loads, is it as flat and level as required – will the trucks run efficiently, are the joints and the surface in good shape?
“None of these should be taken for granted and all can add significant maintenance and running costs to the operation and therefore the return on capital. In worst cases, productivity can be seriously compromised.”
Hulett points out that floors are relatively simple structures. “Our view is that it is best to keep it that way. The engineering of reliable low cost floors depends on good quality materials and good quality construction. Add to that care and attention to the design and positioning of joints and you have the recipe for a good floor. Tenants should be wary of any magic solutions or quick fixes, as in any other walk of life. Above all, tenants and developers should get third party certification from the design, construction, through to floor completion stage. In particular, flatness surveys should not be left to the flooring contractors.”
Face is routinely consulted on upgrading of floors, he says, usually to deal with floor surface, joints and flatness problems. “On surface problems, the first thing to note is that no applied coatings, paints and overlays are as durable as the original concrete and careful thought needs to be given to using such products. They often incur more maintenance cost over time than the original floor. It is advisable to avoid painting floors to improve appearance. Where there is paint on a floor, the first question to ask is – what is being covered up? Joints are usually easy to fix but require well engineered solutions – not just a sticking plaster approach that lasts five minutes.”
Flatness challenges occur routinely on both old and recently laid floors, says Hulett. “Survey data on many floors is often unreliable and it is essential that surveys are carried out by independent and competent surveyors. Once the survey results have been collected and analysed, decisions can be taken on improving truck productivity. This invariably means grinding of the floor to some extent. There are no effective cheap solutions. Good investment decisions need to be based on sound engineering, good quality materials and workmanship,” he says.
Twintec has been championing the use of steel fibre reinforced concrete. Commercial director Darryl Eddy says that the traditional ground-bearing floor slab construction uses concrete nominally reinforced with fairly light mesh and then incorporates saw-cuts to induce shrinkage cracks to a pre-planned grid. Floors with such joints are prone to curl, and are very bumpy for forklifts, eventually leading to breakdown and ongoing maintenance for both floor and machines.
Steel fibre reinforced concrete replaces all reinforcing bar / mesh with high tensile steel wire fibres which changes the concrete’s behaviour from a brittle material to a ductile one that can redistribute internally developed stresses.
Eddy says this development in materials technology together with laser-controlled concrete placement equipment is allowing Twintec to produce floors to a standard suited to the needs of a modern warehouse.
And, he says, the system is fast – large pour construction methods with daily outputs of up to 2,000 sq m a day. In addition, contraction joints are eliminated, and high flatness tolerances achieved without the need for remedial grinding enabling forklifts to operate at optimum speeds.
The incorporation of steel fibres also enhances the load carrying capability of the floor slab and its durability.
SFRC technology can be used to produce heavily reinforced floors that do not require sawn induced contraction joints. Jointless floor slabs mean less wear and tear on forklifts and reduced maintenance on the floor. Eddy says the system can eliminate 90 per cent of floor joints compared to jointed floors, providing greater flexibility in use of racking on the site.