Concrete Floors in Kent

A ground-bearing floor transfers its load straight into the ground beneath it through a compacted sub-base. It is the normal domestic solution and the normal solution for a workshop or a warehouse on competent ground.

A suspended floor spans between supports and carries its load to them instead. That covers a beam-and-block floor with a structural topping, and a reinforced slab spanning between beams or walls. Suspended floors are designed by an engineer without exception, and the designation on the design is what gets ordered.

Knowing which one you have changes the mix, the reinforcement and the volume, so it is the first question rather than a detail.

What goes under a ground-bearing floor

The build-up runs, from the bottom: compacted hardcore or MOT Type 1; a sand blinding; a damp-proof membrane lapped and taped and joined to the wall damp-proof course; rigid insulation where the building is heated; a slip layer over the insulation; then the slab with its reinforcement.

The membrane is the part that goes wrong. A membrane punctured by sharp hardcore, or lapped but never taped, or stopped short of the damp-proof course, will let ground moisture through into a floor finish months after everyone has left. It costs almost nothing to get right and a great deal to put right.

Choosing a floor mix

A domestic garage floor or an unheated store is commonly poured in GEN3. A floor carrying racking, plant, forklifts or vehicles is a designed element and takes a reinforced concrete class from the specification.

Reinforcement in industrial floors has moved substantially towards fibres, either steel or macro synthetic, batched into the concrete rather than laid as mesh. That removes the fixing work and the risk of mesh being trodden to the bottom of the slab where it does nothing. Which is right for your floor is a design question, and we quote whichever the specification names.

Power floating and surface flatness

A power-floated finish gives a dense, hard, dust-resistant surface, which is why it is standard in warehouses and workshops. It is a timed operation: the concrete has to be worked at the right point in its set, which is a matter of hours, not a job that can be left until tomorrow.

Where a floor has to meet a flatness tolerance, that tolerance is normally specified against Concrete Society Technical Report 34, which is the reference document for industrial floor construction in the UK. If your floor has a TR34 classification attached to it, tell us, because it affects the consistence of the concrete supplied as well as the way it is finished.

Estimating floor volume

Floor area times slab thickness, in metres. A workshop floor 10 metres by 8 metres at 150mm is 10 x 8 x 0.15, so 12 cubic metres.

Add anything that is thicker than the field of the slab. Thickenings under stanchion bases, machine plinths, an edge beam around the perimeter and a step down at a doorway all take concrete and none of them appears in the area calculation. On a large floor these add up to considerably more than people expect.

Pouring a floor inside a building

A floor is usually poured into a structure that already exists, which is what makes it different from every other pour. The concrete has to get through a door opening, around a frame, or over a threshold, and the lorry has to stand outside.

Three answers cover most floors. A pump line runs through the opening and places the concrete where it is wanted. A volumetric mixer stands outside and discharges into barrows or a dumper. Or a mini-mix vehicle gets closer to the opening than a full-size lorry could. Kent Readymix asks what the building is, where the opening is and what stands between the two, so an approved supplier can send the right combination.

Next steps for a floor pour

Send the floor area, the slab thickness, whether it is ground-bearing or suspended, what will run across it, and how the concrete would reach the opening. Where you have a structural specification, the designation and any TR34 classification on it are what we quote against.

Most of our approved suppliers work on a pay-for-what-you-use basis. Your quotation, delivery and payment are agreed directly with the approved supplier appointed to your pour.