Cold Store and Freezer Room Floor Coating

Short answer: a cold store or freezer room floor has to withstand low temperatures, freeze–thaw cycles, sudden temperature changes at doors and during cleaning (thermal shock), forklift traffic, condensation and the risk of slipping, all at the same time. The systems whose DEMCO data sheets list cold stores are the PU concrete DEMCO PUR 303 CONCRETE SL 20 UB/WB, the polyurethane self-leveling coatings DEMCO PUR 363 SELF (elastic) and DEMCO PUR 350 SELF (semi-elastic), and the spray polyureas DEMCO POLYUREA /HB and DEMCO POLYUREA /PURE. In practice, the floor is coated before the room is cooled down, at the application temperature given in the data sheet. The PU concrete is not suitable for use below -5 °C; for rooms that will operate at very low temperatures, such as freezer rooms, define the system and the temperature limits together with our technical team.

The values below are taken from the DEMCO technical data sheets of these products and their primers.

What must a cold store floor withstand?

In practice, these are the loads that put the most strain on a cold room floor:

• Low temperature: hard, brittle coatings crack more easily in the cold; the coating must stay flexible and keep its bond.
• Freeze–thaw: during defrosting, maintenance and breakdowns, the floor freezes and thaws again and again.
• Thermal shock: warm and cold air meet at the doors; cleaning with hot water or steam creates a sudden temperature difference on the cold surface.
• Forklifts and pallet trucks: loaded wheels, turning and dropped pallets cause impact and wear.
• Condensation and slipping: humid air entering through an open door condenses on the cold floor and forms frost and ice; the surface must be slip-resistant.

In practice, the thermal insulation and vapor barrier under the slab are dealt with separately in the cold room design; a floor coating does not replace them.

DEMCO systems whose data sheets list cold stores

Product	Type	Area of use in the data sheet	Key properties	Thickness / consumption
DEMCO PUR 303 CONCRETE SL 20 UB/WB	Water-based, heavy-duty PU concrete	Cold stores	Resistant to thermal shock, unaffected by freeze–thaw cycles; resists intermittent live steam and hot-water cleaning; slip resistance R11 (EN 16165); compressive strength 75 MPa	6 mm or more
DEMCO PUR 363 SELF	Solvent-free, elastic polyurethane self-leveling coating	Cold stores and warehouses	Works together with the substrate, unaffected by sudden temperature changes	1.8–2.0 kg/m² per 1 mm
DEMCO PUR 350 SELF	Solvent-free, semi-elastic polyurethane self-leveling coating	Cold stores	High impact and tear strength	1.8–2.0 kg/m² per 1 mm
DEMCO POLYUREA /HB	Hot-spray pure polyurea	Cold room facilities, warehouse floors	Elastic even at low temperatures; 435% elongation; seamless, monolithic surface	Theoretically 1.1 kg/m² per 1 mm
DEMCO POLYUREA /PURE	Hot-spray pure polyurea	Cold storage facilities, warehouse floors	Flexible at low temperatures; ready for use in a short time	Theoretically 1.1 kg/m² per 1 mm

All five products have been tested to EN 1504-2 under CE marking. The data sheets of DEMCO PUR 363 SELF, PUR 350 SELF and the polyureas give no value for the minimum service temperature; the -30 °C in the polyurea data sheets is given as the temperature down to which application is possible. According to its data sheet, DEMCO PUR 303 CONCRETE SL 20 UB/WB is not suitable for use below -5 °C; if the room will operate at lower temperatures, define the system with our technical team before ordering. The product is applied at an ambient temperature of 10–35 °C.

Which system for which area?

Area	Main load	Candidate DEMCO system according to the data sheets
Freezer room	Very low temperature, freeze–thaw	System defined with our technical team; DEMCO PUR 303 CONCRETE SL 20 UB/WB is not used below -5 °C
Cold store	Forklift traffic, condensation	DEMCO PUR 303 CONCRETE SL 20 UB/WB, DEMCO PUR 350 SELF or DEMCO PUR 363 SELF
Door areas and loading transitions	Thermal shock	DEMCO PUR 303 CONCRETE SL 20 UB/WB or DEMCO PUR 363 SELF
Cold rooms washed with hot water or steam	Thermal shock, slipping	DEMCO PUR 303 CONCRETE SL 20 UB/WB (R11)
Areas needing a seamless surface and short downtime	Quick return to service	DEMCO POLYUREA /HB or /PURE

These data sheets give no separate value for forklift loads, and only DEMCO PUR 303 CONCRETE SL 20 UB/WB has a slip resistance class. Define the traffic load and the need for a slip-resistant surface with our technical team during the project. For hygiene and coving details in cold rooms that belong to food production, see the food facility flooring guide.

Layer build-up

Step	DEMCO PUR 363 SELF / PUR 350 SELF	DEMCO PUR 303 CONCRETE SL 20 UB/WB	DEMCO POLYUREA /HB and /PURE
Surface preparation	Oil, rust, dust and loose layers are removed; the surface is roughened by shot blasting, grinding or milling and must be free of moisture	Dust and loose material are removed, preferably by vacuum; existing expansion and movement joints are carried through the new floor	Milling, water jetting or blasting; average pull-off strength of the substrate 1.5 N/mm², compressive strength at least 25 N/mm², moisture max. 4%
Primer	DEMCO EPOX 100 PR; main coat once the primer is touch-hard, after about 24 hours	DEMCO EPOX 110 PR; wait at least 12–24 hours at 15–30 °C until it is touch-hard	DEMCO EPOX 110 PR; two coats may be needed on very absorbent concrete
Main coat	Spread with a notched trowel, air released with a spiked roller	Spread to 6 mm with a notched steel trowel, air released with a spiked roller	Sprayed with a heated-hose 1:1 machine at min. 2000 psi and 65 °C
Topcoat and details	One coat of acrylic polyurethane semi-matte topcoat at 0.150 kg/m²	Joints are filled with a joint filler suited to the expected movement and the intended use	Recoat time: 1 hour for /HB, 6 hours for /PURE

DEMCO PUR 303 CONCRETE SL 20 UB/WB is not applied to asphalt, weak or friable concrete, unmodified sand/cement screeds, or PVC tiles or sheets. According to its data sheet, DEMCO PUR 303 CONCRETE SL31 COVING/WB is coated with DEMCO PUR 303 CONCRETE SL 23 UT/WB once it has cured. For details on polyurea application, see What is polyurea waterproofing?

Application temperature and curing

Product	Ambient temperature	Substrate temperature	Moisture	Curing
DEMCO PUR 363 SELF and PUR 350 SELF	15–30 °C	Ideally 15–30 °C; must never be below 10 °C	Substrate below 4%; ambient humidity below 80% for 363 and below 65% for 350	Full cure in 7 days on average when applied at 20–25 °C
DEMCO EPOX 100 PR and 110 PR (primers)	15–30 °C	Ideally 15–30 °C; must never be below 10 °C	100 PR: substrate below 4%, ambient below 80%; 110 PR can be applied to damp surfaces	Full cure in 7 days on average when applied at 20–25 °C
DEMCO PUR 303 CONCRETE SL 20 UB/WB	10–35 °C	To be confirmed with the technical team	Not used on substrates with rising damp or osmosis problems, or in environments with relative humidity above 75%	Full cure in 7 days
DEMCO POLYUREA /HB and /PURE	Can be applied down to -30 °C	–	Surface moisture max. 4%	Touch dry in 10–15 seconds (/HB) and 15–20 seconds (/PURE)

• Coat before cooling: in practice, the floor is coated before the room is cooled down, and cooling is switched on once the full cure time in the data sheet has passed. According to the data sheet of DEMCO PUR 363 SELF, the time between coats also gets longer at low temperatures.
• Polyurea and primer: although polyurea can be sprayed in the cold, the concrete is first primed with DEMCO EPOX 110 PR, which requires a working temperature of 15–30 °C; define the priming conditions with our technical team.
• Renovating a cold store in use: in practice, the room is emptied and brought up to the application temperature; no ice, frost or water may remain on the floor, and the surface temperature should be kept at least 3 °C above the dew point. For moisture measurement, see the concrete moisture guide.

Frequently asked questions

Which floor coating is used in a cold store?

The DEMCO systems whose data sheets list cold stores are PU concrete, polyurethane self-leveling coatings and spray polyurea; the products are listed in the table above. The choice depends on the operating temperature of the room, the cleaning method, the traffic load and the downtime available.

Can PU concrete be used in a freezer room?

According to its data sheet, DEMCO PUR 303 CONCRETE SL 20 UB/WB is not suitable for use below -5 °C, so it is not used in freezer rooms that operate at lower temperatures. The product is resistant to thermal shock, unaffected by freeze–thaw cycles, and its data sheet lists cold stores among its areas of use. For a freezer room, define the system with our technical team before ordering.

Can the floor be coated while the cold room is running?

Polyurethane self-leveling coatings and their primers require a working temperature of 15–30 °C, and the substrate must not be below 10 °C, so they are not applied while the room is cold. The polyurea data sheets give an application temperature down to -30 °C, but the temperature requirement of the DEMCO EPOX 110 PR primer must also be met.

When can cooling be switched on after coating?

DEMCO PUR 363 SELF and PUR 350 SELF reach full cure in 7 days on average when applied at 20–25 °C, and DEMCO PUR 303 CONCRETE SL 20 UB/WB reaches full cure in 7 days. In practice, cooling is switched on once this time has passed. Polyurea is touch dry within seconds; because the data sheets give no full cure time, the time to start cooling is set with our technical team.

Is epoxy used in cold stores?

The data sheets of DEMCO epoxy floor coatings do not list cold stores among their areas of use. In practice, hard coatings are more prone to cracking under the sudden temperature changes at doors. For a comparison, see Epoxy or polyurethane?

Tell us the operating temperature of the room, the door and loading layout, the cleaning method, the forklift traffic and the downtime available in the quote form, and our technical team will recommend a suitable system and application plan. For all products, see the flooring page.

Related products and systems: polyurethane flooring.