Hygienic detailing: coving, drains and falls

In a food production hall or a commercial kitchen, contamination rarely begins in the middle of a floor. It begins where the floor meets something else: a wall, a drain, a plinth, a door threshold, a steel column. These are the details that are drawn last, priced roughly, and built under time pressure, and they are the details that auditors examine first.

Coving and wall junctions

An unsealed wall to floor junction is an open joint into which water, product residue and cleaning chemicals migrate. Once material is behind the floor it cannot be removed by cleaning, and the resulting growth is invisible until it is smelled. A continuous cove, formed in resin mortar and coated with the same system as the floor, removes the joint and gives a radius that a brush or a hose can actually reach.

The height and radius should follow the cleaning method. A low cove of around 100 mm suits a dry or lightly wetted area. Where hoses are used at height, a cove of 150 mm or more is normal, terminated into a chase or under a wall cladding sheet so that the top edge is protected rather than exposed. The termination matters as much as the cove itself: a coved upstand finished with a raw edge against a painted wall will fail at that edge first.

The same logic applies to plinths under machinery, kerbs around tanks and the bases of columns. Each should be coved and sealed, and each should be detailed so that it can be cleaned from above without water being driven into a gap.

Falls and drainage

Water that stands on a floor is a hygiene problem and a slip problem. Falls should be designed into the screed rather than hoped for from the slab, and they should be continuous to the gully with no flat areas or reverse falls along the route. Practice varies on gradient, and the right value depends on the surface texture, the volume of water and the distance to the outlet: a coarse anti slip surface holds water and needs more fall than a smooth one. Test with water before the floor is accepted, not with a level alone.

Drainage type follows the process. Channels suit wash down areas and lines where water is generated along a length. Point gullies suit localised discharge. Whichever is used, the floor should be mechanically locked into the drain rather than merely butted against it. Stainless steel drains with a flanged or keyed edge allow the resin to be dressed into the body of the drain, which keeps the most heavily loaded joint in the room sealed. Gratings should be removable by hand for cleaning.

Thresholds, joints and penetrations

Doorways between zones of different hygiene status need a defined edge, not a feathered one. Movement joints must pass through the finish and be filled with a flexible, cleanable sealant suited to the chemicals in use. Pipe and cable penetrations should be sealed at floor level with a collar, and anchor bolts should be set and sealed before the wear layer is applied, not drilled through it afterwards.

What to check on a hygienic floor

• Every wall, plinth and column junction is coved, with a protected top edge.
• Falls are continuous to the outlet and verified with water.
• Drains are keyed into the floor finish and are accessible for cleaning.
• Movement joints are carried through and filled with a compatible sealant.
• Penetrations, bolts and fixings are sealed at floor level.
• The cleaning regime and chemicals are known, since HACCP is a guideline rather than a certificate and the detailing must support the plan the site actually operates.