PU Concrete Flooring for Food, Pharma, Cold Stores and Wet Areas

What it is

Polyurethane-cement flooring, often called PU concrete, PU cement or urethane cement: a three-part system of polyurethane resin, hardener and a cement and aggregate powder, mixed on site and laid onto a prepared concrete slab. It cures into a dense, seamless surface several millimetres thick.

The decision turns on the cost of a floor failing inside a working plant. In food, beverage, dairy and pharma production, a floor that cracks, debonds or harbours bacteria can stop a line, fail a hygiene audit and need replacement in an area that cannot easily be shut down. PU concrete is specified where hot washdown, steam cleaning, spillage and temperature swings would break down a thinner or more rigid resin floor.

PU concrete against epoxy

For a broader view of industrial floor finishes see epoxy vs vinyl industrial flooring, and for how resin floors sit against tiles, vinyl and carpet across a whole building, the commercial flooring systems guide.

Thickness and texture by duty

Thickness is the main specification decision, and it should be set zone by zone:

• Self-smoothing grades, typically around 4 to 6mm, for moderate traffic and regular washdown.
• Trowelled heavy-duty grades, typically 6 to 9mm, for heavy traffic, impact and hot washdown.
• Thicker builds where hot oil, boiling water or steam cleaning are frequent.

The system manufacturer publishes the temperature and duty limits for each thickness, and those limits, not a generic figure, should go into the specification.

Anti-slip texture is set by broadcasting aggregate or by the trowelled finish. More texture improves grip on wet and greasy floors but is harder to clean, so the texture should match the contamination and cleaning regime of each room.

Detailing that decides whether it lasts

Substrate preparation. The concrete must be sound and mechanically prepared, by shot blasting or grinding, to remove laitance. Weak or contaminated concrete must be cut out and repaired first; EN 1504-2 covers surface protection products for concrete where the base itself needs treatment.

Keyed edges. At every free edge, drain, threshold, day joint and plinth, a groove is cut into the slab so the screed locks in.

Coving. A coved skirting formed in the same material carries the floor up the wall in a radius, removing the floor-wall corner where dirt and bacteria collect. In pharma and food areas this is normally part of the hygiene design; see pharma and life sciences.

Falls and drains. A resin floor will not correct a flat slab. Falls to drains must be built into the concrete or screed below, and drains and channels should be hygienic types bonded into the floor. The fall pattern is set by the designer against the process layout.

Movement joints. Structural movement joints in the slab must be carried through the floor with a suitable sealant, not covered.

Hygiene and cleaning. The appeal of PU concrete in food and pharma areas is a seamless, impervious surface with no grout lines, coved at the walls and bonded to the drains, so there is nowhere for water and residue to sit. That only holds if the cleaning regime is agreed when the floor is specified: the chemicals, water temperature and equipment used every day decide which grade and texture survive. Repairs should be made with the same system, cut back to sound material and keyed in, rather than patched with a general-purpose mortar that leaves a joint.

Programme. Resin floors are one of the last trades in a process area, and they need the area closed, dry, temperature-controlled and free of other trades while they are laid and cured. Planning that window early avoids a floor laid in a rush around equipment installation.

Slab design and preparation are part of industrial flooring and hardstanding.

Common mistakes

• Choosing epoxy for a hot washdown area because it was cheaper or familiar.
• One thickness throughout the plant, so the hot zone fails first.
• No keyed edges, and the floor lifts at drains and doors.
• Laying on a flat slab and expecting the resin to create falls; water ponds.
• Bridging movement joints, so the floor cracks along the slab joint.
• Applying in poor ambient conditions, since cure depends on temperature and humidity.

What to ask your contractor or supplier

• Which system grade and thickness for each zone, against which process conditions?
• What substrate moisture and strength limits apply, and how will they be tested?
• How are edges, drains and joints terminated?
• What coving detail and anti-slip texture are proposed?
• How will the floor be cleaned, and is the texture compatible with that regime?

Standards referenced

Synthetic resin screed materials, including polyurethane, are classified under EN 13813. Surface protection systems for concrete under EN 1504-2. Thickness, temperature limits, falls and hygiene detailing for a particular facility must be confirmed by the project's civil engineer and process designer against the system manufacturer's published data.