Walk on by

All too frequently the floor gets overlooked, and it often seems to take an accident or for equipment to get damaged before it gets a second look. Lucy Tesseras thinks it deserves better

It’s a high-tech piece of kit, yet people think nothing of walking all over it. It is of course, the warehouse floor – and it plays an integral role in ensuring the smooth and efficient running of any operation.

Kevin Dare, managing director of the CoGri Group, says: “The floor is the table-top from which a client runs its operation. A better quality floor will result in increased throughput, increased performance and reduced maintenance to the floor, and the materials handling equipment that runs on it.”

But all too frequently it is overlooked, and it often seems to take an accident or for equipment to get damaged before the floor gets a look in.

“It’s foolhardy to not look after the floor properly,” warns Dare. “If you have a poor floor you’ll end up with poor performance. Operations will slow down so you’ll need more forklifts and more staff to move product around in the distribution centre, which in turn will cause more damage to the floor, so again more maintenance will be needed. It becomes a cycle of poor performance and one that could be easily avoided if the proper care and attention is taken.”

The stitch in time approach doesn’t seem to happen with floors though and maintenance is not carried out as frequently as it should be.

If the floor is looked after and maintained properly then 80 per cent of the problems associated with a poor floor can be eliminated, says Dare. The cost is also minimal if repairs are carried out proactively rather than reactively.

“Yearly checks are carried out on forklift trucks, on racking and on most other equipment used in a distribution centre, so why isn’t it automatically carried out on floors?”

When it comes to maintaining the durability and safety of a floor Rodney Arnolds, chairman of flooring specialist Permaban, says companies need to accept that cracks are generally not a failure in the floor, but are a result of the natural shrinkage of the concrete during the drying out process. He says: “Attention to proper design and jointing layout can minimise potential cracks but cannot be guaranteed. Joints are no more than designed cracks that go in a straight line whereas a crack is random. Cracks can easily be repaired with the right systems.”

To help minimise the problem he recommends a floor joint system that provides 10mm-thick steel joint arris (edges of the joint) protection and proper discontinuous load transfer, which he claims displays four times less vertical movement and is four times stiffer than a joint system made from 5mm-thick steel and costs around £25 per metre to install. Arnolds suggests a non-armoured joint is likely to breakdown more quickly. To reinstate the concrete joint arris will cost £120 per metre to repair, or £150 per metre to post armour the joint with a repair system.

“A good framework system such as Permaban AlphaJoint [should be used] to ensure that the necessary floor joints are adequately armoured and an efficient load transfer dowel system is used. The importance of this is often overlooked,” he says.

Arnolds highlights a comment from Ken Hall, ProLogis’ former managing director of global developments who was responsible for the development of the ProLogis floor specification: “For a distribution centre there are two important elements, one is a roof that does not leak…but the most important element is a good floor as this is the platform on which the whole operation takes place. Damage to floor joints was the biggest problem ProLogis had until we specified Permaban AlphaJoint in our specification for the floor and since doing so we no longer have the problem.”

For a distribution centre there are two important elements, one is a roof that does not leak…but the most important element is a good floor as this is the platform on which the whole operation takes place.Floor markings also need to be cared for properly in order to prolong their durability.

ASG Services says dirt is the main cause of long-term damage to floor markings, but regular cleaning can help reduce the potential impact and provide a visually stronger marking. The line marking and warehouse safety specialist says dust and dirt are abrasive to the paint, and if left liquid spills can result in staining and damage.

It advises companies to follow a floor maintenance plan based on the following criteria: sweep the floor with a brush or mechanical cleaner; wash and scrub it regularly using the correct detergent; avoid using stiff bristle brushes or caustic and solvent-based solutions as they are likely to cause dulling; place mats at entrance doors to reduce dirt and moisture being transferred to the floor; avoid sliding or dropping heavy and pointed equipment; do not drag or push pallets; and repair any significant damage as soon as possible.

With environmental concerns at the forefront of many businesses’ agendas today, Permaban’s Arnolds suggests there are a number of ways to improve the eco-credentials of a floor.

He says it’s important to properly calculate slab thickness using a modern design approach so that the floor is neither under or over specified regarding thickness. Many engineers seem to work on the basis that a thicker slab worked last time so they might as well use the same thickness this time, which can result in excess concrete being used, Arnolds reckons.

He adds that a good light reflective dry shake topping can also reduce the lighting requirement by improving reflectivity by more than 50 per cent compared to natural concrete. Arnolds believes it can also “improve the abrasion resistance of the concrete surface thus allowing a lower grade concrete to be used with a reduced cement content”.

Kevin Dare adds that concrete and steel manufacturing is “about the worst contributor of carbon dioxide emissions so looking at ways to design floors with reduced cement is a long-term challenge.”

From Russia with love:
Permaban Floor Solutions has completed a project for real estate company Giffels Management Russia on a 600,000 sq m distribution centre near Moscow.

Giffels is focused on the warehousing and logistics sector within Russia and is in the process of developing an industrial real estate portfolio.

Permaban, working alongside main contractor Megastroy and Russian flooring contractor Romex, was briefed to provide a high durability floor with a professional appearance that required minimal maintenance.

The company supplied 3,500m of its AlphaJoint Formwork system, complete with joint intersections, 305 tonnes of its FibreTop Natural Grey Floor Hardener and 6,200 litres of Permaseal cure/seal product for the first area of 65,000 sq m.

The Permaban/Romex team used large area casting techniques, the Somero SXP Laser Screed and Somero Topping Spreader to achieve an FM1 flatness tolerance on bay sizes of 24m wide between columns and 48m long bays.

Each pour was contained inside Permaban’s AlphaJoint leave-in-place formwork system, which was fixed using AlphaFix.

The floor was designed as a 200mm- thick nominally reinforced floor with locally produced square panelled mesh reinforcement, incorporating wire at 150mm centres in both directions to provide the equivalent of a BS A193 mesh.

To aid the tolerance achievement, Permaban decided to place the concrete from the back of the truck rather than pump the concrete, which would have required a modified, less simple concrete mix design.

The mesh was initially laid on to the slip membrane, which allowed the trucks to reverse into position to place their load. Just before the concrete was placed the mesh was set up on spacers to provide 50mm bottom cover.

By using AlphaJoint with AlphaFix the bay closing form work did not have to be placed until the laser screed was on its penultimate pour for the bay, as it can be installed and micro adjusted for line and level.

This allowed the concrete truck to back down directly to the position of placement without having to turn on the reinforcement and slip membrane, helping to prevent rucking of the slip membrane and rutting of the sub base.

As the concrete was being placed level checks were consistently carried out to ensure the levelled concrete and the formwork at the edge.

The surface was then skip floated and straight edged following the levelling by the Somero SXP Laser Screed.

Before and during the power floating and power towelling operations, further straight edging and level checking was done, both within the general floor area and across the joints.

Permaban says there were initially considerable problems with the concrete slump consistency and delays between concrete trucks arriving on site, which resulted in the first day’s pour taking some 15 hours to place.

However, measurement readings after the first day demonstrated that category FM1 properties II and IV had been achieved with only two per cent of the measurement falling above the 95 per cent requirement, and without any grinding.

Tesco floors it in Malaysia:

Supermarket giant Tesco enlisted newly formed CoGri Malaysia to construct a special floor slab at its largest purpose built distribution centre in south east Asia.

The 50,000 sq m warehouse, sited just north of Kuala Lumpur, is built on a 25-acre plot, which includes 24,000 sq m for expansion.

The main hub features 169 loading docks and 54,000 pallet spaces in 11m high selective racking.

Face Consultants designed and specified the floor flatness as FM2 Special from the UK Concrete Society’s Technical Report No 34.

The consultancy specified 2.4m x 2.6m pile grid, 900 diameter pile heads, 200mm thick sub base, 210mm thick slab with 45kg/cu m HE+1/60 metal fibres, AD10 armoured joints, 5kg of fibre suppressant dry shake and Masterkure 181 Acrylic Curing System.

The tolerances are designed to allow the conversion from conventional to narrow aisle racking storage with very little floor flatness upgrading required.

To avoid casting during the heat, batching plant staff began work at 2.30am, with the first truck arriving on site at 4am.

Following fibre batching, the concrete was placed direct from the truck in four metre wide strips and then struck to tolerance with a Somero S240 Laser Screed.

The laser-controlled head incorporates an auger which strikes the concrete and pushes excess material out to the right side of the 12 foot wide head before a vibrator and a finishing blade smooth the just struck concrete surface.

The only manual compaction of concrete is done around the perimeter joints to ensure the load transfer dowels on the armour joints are fully enclosed with concrete.

The project was carried out by a 39-man team who placed 10,500 cu m of concrete and 47 tonnes of fibre over 41 days of casting.

The last load of concrete was generally placed by 1pm with finishing works completed seven to nine hours later.

Erection of the racking and racking sprinklers began 20 days into casting.