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

> PU concrete flooring is a polyurethane-cement screed: a resin and cement hybrid trowelled or poured onto concrete, usually several millimetres thick. Compared with epoxy it better tolerates hot water, steam cleaning, thermal shock and some substrate moisture, which is why it is used in food plants, pharma production, cold stores and wet process 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

| Factor | PU concrete | [Epoxy flooring](/materials/epoxy-flooring) |
| --- | --- | --- |
| Thermal shock and hot water | Good; tolerates steam cleaning and hot spillage within system limits | Poor to moderate; can crack or debond |
| Substrate moisture | Generally tolerates more; check system limit | Needs a dry slab |
| Typical thickness | Several millimetres (screed) | Thin coat to several millimetres |
| Finish | Matt, textured | Smooth or textured, often glossy |
| Colour stability in daylight | Often yellows | Standard epoxy yellows and chalks |
| Typical areas | Food processing, pharma wet areas, cold stores, washdown zones | Dry production, stores, workshops, plant rooms |

For a broader view of industrial floor finishes see
[epoxy vs vinyl industrial flooring](/compare/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](/blog/commercial-flooring-systems-guide-india).

## 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](/industries/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](/services/construction/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.

## Frequently asked questions

### What is the difference between PU concrete and epoxy flooring?

Both are resin floors on a concrete base, but they behave differently under heat and water. PU concrete is a polyurethane and cement hybrid that is less rigid and tolerates hot water, steam cleaning and sudden temperature changes far better. Epoxy is harder and glossier and suits dry areas, but can crack or debond under repeated thermal shock. The usual split is PU concrete for wet, hot or cold process areas and epoxy for dry production and stores.

### How thick should a PU concrete floor be?

It follows the duty. Self-smoothing grades are typically around 4 to 6mm for moderate traffic and washdown, and trowelled heavy-duty grades typically 6 to 9mm, rising further where hot spillage, steam cleaning or heavy impact are severe. The exact thickness for each zone should come from the system manufacturer's data against the process conditions, and be stated on the drawing room by room.

### Is PU concrete suitable for cold storage?

It is commonly used in cold stores and blast freezer areas because it copes with low temperatures and with the shock of washing at temperatures very different from the room. The bigger risks in cold rooms are usually the slab beneath it, including insulation and frost protection under the floor, which are designed by the cold store engineer rather than the flooring applicator.

### Does PU concrete floor change colour?

Often, yes. Many polyurethane-cement systems yellow or darken under ultraviolet light, including daylight through windows. It is generally a cosmetic change and does not affect performance, but lighter colours show it most. Where appearance matters, ask the supplier how the chosen colour behaves in daylight before approving it.

### Why does PU concrete need anchor grooves at edges?

Because the screed is under stress from temperature cycling, and a free edge is where it starts to lift. At perimeters, drains, door thresholds, day joints and around plinths, a groove is cut into the concrete and the screed is filled into it to lock the edge down. Skipping these keyed terminations is one of the most common reasons a PU floor starts to curl and debond at the edges.

## Sources

- [EN 13813](https://standards.cencenelec.eu/ords/f?p=CEN:105) — Screed material and floor screeds — screed material — properties and requirements (synthetic resin screeds)
- [EN 1504-2](https://standards.cencenelec.eu/ords/f?p=CEN:105) — Products and systems for the protection and repair of concrete structures — surface protection systems for concrete

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Source: https://hagerstone.com/materials/pu-concrete-flooring