The importance of a good warehouse floor

By David Luton, President David Luton, Associates -- Modern Materials Handling, 3/1/2001

Give me a good floor and a good roof," warehouse managers say. Floors, for example, often impact other handling systems within the warehouse-such as pallet racks, carton flow racking, mezzanines, automated storage and retrieval systems, conveyors, horizontal carousels, and narrow-aisle lift truck operations.

From a materials handling perspective, good floors involve three factors: the floor subbase, its surface, and the type of floor construction itself.

Most warehouse managers hope they will never have to be concerned about the subbase and major problems such as settling.

In case of a major floor failure, get proper independent technical advice. Document your activities carefully. There is a good possibility you may end up in court to resolve matters.

More warehouse managers also need to pay attention to the floor surface. A large number of floor coatings and sealings are available. New floors are especially good candidates for protective sealing. When the floor is new, access is restricted so a coating can be applied easily and without interference.

Properly protected floors result in easier cleaning, longer floor life, and an improved work environment. Protected floors also reduce the risk of dust settling on product.

The concrete floor and its construction are the most important parts of the interface with materials handling systems. As one general rule, the narrower the aisle, the more critical the floor construction, particularly its flatness.

To improve durability, some floors-and especially ones in high traffic areas-may be constructed of a base slab and a specially designed non-dusting topping.

A conventional floor can have wire mesh and/or rebar within it. There also may be various other strengthening elements, such as various fibers or fillings. But be especially careful if you now use or later plan to install wire guidance for narrow-aisle trucks or for automatic guided vehicles. Some types of metallic fillings can interfere with the wire guidance system.

Some other general principles behind concrete floor slab design are worth noting:

• If you inherit a weak floor from a prior warehouse occupant, investigate conditions with your storage system designer. Alternative storage designs can reduce point loading.

• For higher height buildings, make sure the floor is designed to support the racking system point load.

• On a total system cost basis, increasing the size and thickness of racking base plates may be a cheaper alternative than strengthening the slab. Keep in mind, however, that with some types of lift trucks there may be problems. In the case of trucks with outriggers, the oversized base plates may damage the front wheels when the truck needs to make a right-angle turn into the rack to put away a pallet.

• Remember that load-bearing structures, walls, columns, and the like usually require footings under them. These structures should not be placed directly on a non-strengthened floor. Design also for the future (for example, putting in a mezzanine later on). By pouring any necessary footings when the floor is first constructed, you will avoid operating disruptions and expenses later on.

• In lightly reinforced floors, the slab should be sawcut to reduce cracking. Co-ordinate your rack and floor designs so that many of the sawcuts are contained under the rack grid.