Watco Concrex Cold Set - Epoxy Repair Mortar


Long lasting, heavy-duty formula for concrete repairs in cold temperatures, making it ideal for winter use and cold room conditions. Provides superior strength and adhesion making it ideal for very thin section, feather- edge or intricate repairs.

  • Cures at 0°C
  • Virtually indestructible
  • Impervious and non-dusting
  • So strong it can be feather-edged
  • Maximum strength is achieved at only 5mm thick. May be applied at up to 50mm thick for patch repairs
  • Areas of use include permanent repairs for:
    • Holes in concrete floors, damaged steps, broken floor joints
    • Eroded, uneven concrete, worn and holed floors
    • Fitting guide rails, spalled expansion joints

Note: While great care is taken with the colour samples shown, no guarantee can be given that they represent exactly the colours offered.

£121.64(ex. VAT)
£145.97 (inc. VAT)
Please choose your colour
Available for Delivery (See Delivery Options Below)


Watco Concrex Cold Set provides heavy duty floor repairs in temperatures as low as 0°C.

Compared with other repair mortars this formulation is particularly rich in epoxy resin. This provides superior strength and adhesion making it ideal for very thin section, feather- edge or intricate repairs.

Maximum strength is achieved at only 5mm thick. May be applied at up to 50mm thick for patch repairs.

A primer is not generally required, Watco Concrex Cold Set can be used to repair holes with minimal preparation - see section headed ‘Priming’.

In common with all Watco Concrex products, Watco Concrex Cold Set has good resistance to a wide range of chemicals commonly found in industry.

A repair using Watco Concrex Cold Set is ready for light traffic in 24 hours at 0°C, or 6 hours at 10°C.

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Features & Benefits

  • Areas of use - permanent repairs for:
    • Holes in concrete floors
    • Damaged steps
    • Broken floor joints
    • Eroded, uneven concrete
    • Worn and holed floors
    • Fitting guide rails
    • Spalled expansion joints
  • Heavy-duty, two-part epoxy resin mortar
  • Cures at 0°C for all year-round maintenance
  • Virtually indestructible
  • Coloured and deep fill versions available
  • Good chemical resistance
  • Resin rich for thin section and feather-edge repairs
  • Suitable for interior and exterior repairs

Surface Preparation

Surfaces should be clean, dry, and free of all loose material. Wire brushing or sweeping is generally sufficient. Watco Bio-D degreaser can be used to remove grease and oil. If the surface is damp, it can be primed with Watco Tack Coat.


The resin content of Watco Concrex Cold Set is very high. This means that a primer is not usually required when filling holes in concrete floors or resurfacing rough or damaged concrete.

Watco Tack Coat adhesive primer is recommended when using Concrex Cold Set as a thin section screed over smooth surfaces. It is also recommended when repairing intricate/high impact areas such as broken floor joint edges, and damaged step nosings. Watco Tack Coat can also be used at the same low temperatures as Concrex Cold Set.

Watco Concrex Cold Set should ideally be applied to a dry surface, but if the surface is damp Watco Tack Coat should be used as a primer.


Wear protective gloves.

The resin and the sand are already pre-blended. There are 4 bottles of grey curing agent supplied with a 10kg unit of Concrex Cold Set, and larger bottles of grey curing agent in the 25KG packs.

The curing agent is added to the sand/resin at point of use, and once mixed the mortar should be used within 30-60 minutes depending upon temperature.

Do not mix inside the plastic bucket. Tip the sand/resin into a mixing tray or on a board.

Shake the bottles of curing agent until the liquid is a uniform grey. The tins of coloured curing agent should be stirred thoroughly.

Form the sand/resin into a mound and leave a small hole in the middle. Empty the curing agent into the hole, ensuring the tin is completely drained.

Carefully mix the aggregate with the curing agent using a trowel until a smooth mortar is obtained, this will take several minutes. The more thorough the mixing, the ‘wetter’, smoother and more manageable the mix becomes. Alternatively, you can knead the mixture by hand wearing suitable gloves. It is important to mix thoroughly until you achieve a consistent colour. A ‘Cretangle’ or suitable open pan mixer can be used to mix large quantities.


Trowel the mortar firmly into the repair and finish with a trowel or float. To get a good smooth finish, regularly wipe the surface of the trowel with a cloth dampened with white spirit.

Watco Concrex Cold Set/Colours Cold Set are normally applied at 5-50mm thick, but repairs can be feather-edged if most of the repair is at least 5mm thick. For repairs deeper than 50mm, apply in separate layers allowing 6-8 hours between layers, or use Watco Concrex Deep Fill Cold Set which can be applied at 15-100mm thick in one layer.


Do not apply to wet surfaces.

Watco Tack Coat should be used for application to damp surfaces before applying Watco Concrex Cold Set.

Please refer to Watco Tack Coat data sheet for further information.

These products should not be subjected to temperatures above 60°C.

Product Details

Data sheet

For Use By
Consumer Use
Interior / Exterior Use
Interior and Exterior
For Use On
For Use On
Metallic Substrates
Application Method
Steel float or trowel
Single, Two or Three Pack
Pack Size
10kg: 1.2m2 at 5mm thick
25kg: 3m2 at 5mm thick
Compatible Primers
Not usually – see section headed ‘Priming’.
Tensile Strength
Cold set: 15.4 MN/m2
Concrete: 3.4 MN/m2
UN Number
Layer Thickness
Up to 50mm for hole filling only.
Do not use at more than 15mm for screeding.
Resistance to chemicals
Resistance to chemicals
Resistance to chemicals
Caustic Soda
Resistance to chemicals
Oxalic Acid
Resistance to chemicals
Resistance to chemicals
Nitric Acid
Resistance to chemicals
Sugar Solution
Resistance to chemicals
Citric Acid
Resistance to chemicals
Resistance to chemicals
Resistance to chemicals
Hydrochloric acid
Resistance to chemicals
Sulphuric Acid
Pot Life
30-60 minutes depending upon temperature.
Compressive Strength
Cold set: 55.2 MN/m2
Concrete: 21.41 MN/m2
Base Type
Suitable For Use On
Suitable For Use On
Sand and Cement
Suitable For Use On
Suitable For Use On
Concrete Floors
Application Method
Product Type
Product Range
Dry for Light Traffic
At 10°C : 6 hours
At 0°C: 24 hours
Dry for Heavy Traffic
At 10°C: 8 hours
At 0°C: 48 hours
Colour Family

Customer agrees that before placing an Order, Customer has read and understood the most up to date Product Data Sheet for the Product. Where we have access to the Product Data Sheet from the manufacturer, we will either provide a copy on request, or include a link to the Product Data Sheet available on the manufacturer’s website. Customer further agrees that we have no liability for any errors or omissions contained within the Product Data Sheets. For more information, please see our Terms & Conditions of Sale.

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Watco Concrex Cold Set - Epoxy Repair Mortar is only available with the shipping and delivery timescales listed below - please do not contact our Customer Support Team with enquiries about alternative or earlier shipping and delivery times.

Saturdays and Sundays, as well as Bank Holidays, are not classed as working days.

Orders placed after the cut-off for this product will not be processed for earliest dispatch until 9am the next working day.

All delivery costs below are excluding VAT

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