The Concrete Challenge
Mark Leigh of Tremco illbruck explores some options for badly worn or defective industrial floors:
WHETHER you replace industrial floors or how you can repair them presents a challenge, particularly where underfloor heating pipework is present in the slab or screed.
Most specialist flooring contractors rely on the main system suppliers for some level of support in deciding on the right specification for any remedial work. In the first instance they want to be sure of the integrity of the existing floor, with the ever increasing cost of skips and onerous Government targets on waste making full replacement unattractive.
Visual inspection can often reveal a dusty appearance and possibly cracking or potholes – all of which are unsightly and there is also the risk that a badly degraded surface could endanger personnel or damage fragile goods being moved by forklifts.
Further analysis is likely to involve damp meters/hygrometers, ultrasound and core samples. Where UFH is known to be present it may be possible to identify the pipe positions, or avoid them by testing areas such as washrooms where they are often omitted.
It may even be necessary to call in a structural engineer to determine whether a screed complies with BS8204, or to give guidance whether there are serious failings with the continued stability of the slab.
A decision can then be taken on whether to ‘stitch’ the surface, just repairing poor quality areas, to replace the entire floor, or to overlay it. At this point a written specification would be provided, taking into account the type of vehicular or other loadings it will be subjected to, or the intended purpose of a property, for example food preparation or pharmaceutical production.
Preparation for treatment normally features grinding, planing or vacuum shotblasting to remove poor quality material and offer a good key for applying pumped screeds or other treatments. Where contaminants such as grease or chemical spills are present, hot compressed air was commonly used to remove them, but H&S has drastically curtailed the practice and now proprietary sealers are often used; though identifying the contaminant and appropriate treatment is crucial.
High moisture readings must be dealt with. If the property predates 1970s it probably will not have a structural damp proof membrane. So a surface DPM will be required, even if hygrometer readings are below 75%. However, where the problem is linked to residual moisture from the construction, a moisture vapour suppressant will suffice.
The final surface finish, and its flatness, also relates directly to the building’s intended use. For example, pumped screeds are free from trowel marks, and find their own level, within limits. Most underlayments are for smoothing not levelling, and the only way to achieve a standard like SR1 is to pump a water-based smoothing compound. Two-part compounds will not usually self-level though the better ones will self-smooth.
It is possible then to achieve very tight tolerances on levels which might be required to simplify equipment installation for more sensitive production processes. In terms of surface texture there will always be a trade-off between slip resistance and the requirement for more rigorous cleaning regimes.
The long term well-being of building occupants can further be affected by the flooring specification and manufacturers can offer a full range of European directive compliant, low VOC or low odour products: from OPC free smoothing compounds, to adhesives meeting the requirements of EC1 and BREEAM.
The re-screeded and otherwise treated floor can exhibit similar compressive strength to that of structural concrete. Many customers will still choose to have a newly laid screed covered by a cementitious compound and epoxy/PU sealer to enhance the appearance and make it easier to clean.
Meanwhile, where spillages of milk, alcohol and other liquids are anticipated, the specification may switch to polymer or polyurethane screeds. The polymer variety utilise a special additive making them permanently resistant to water and even steam cleaning.
Polyurethane screeds are normally laid at a thickness of 9mm to present the ultimate in durability, being resistant to chemicals, wear and extremes of temperature.
By engaging with a reputable manufacturer and an experienced specialist contractor, Industrial concrete floors can be specified to cope with any conditions or applications.
This article has been reproduced from the Contract Flooring Journal website. You can find them at www.contractflooringjournal.co.uk.