Watco Concrex Flex Epoxy Resin Mortar


    For repairing floors subject to vibration, movement, or impact. Virtually indestructible impact and crack resistant floor repairs.

    • Exceptional impact and wear resistance
    • Chemical resistant and anti-slip
    • Can be feather edged
    • Resistant to vibration
    • Finely graded sand pre-blended with epoxy resin
    • For floors subject to vibration, movement, or impact, including damaged steps, worn floors, holed floors, fitting guide rails, different levels, 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.

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    £121.65(ex. VAT)
    £145.98 (inc. VAT)
    Please choose your colour
    Available for Delivery (See Delivery Options Below)


    Watco Concrex Flex has been specially formulated to resist cracking in areas where floors may be subject to movement, vibration, flexing or impact.

    The two-part epoxy resin mortar has outstanding strength and durability and is modified with an epoxy resin blend that offers a degree of flexibility. This means that it is far less likely to crack or break under impact than a conventional floor repair mortar.

    Watco Concrex Flex also has excellent chemical resistance and cures quickly to allow the floor to be put back into use. Heavy duty thin section floor repairs are so strong that they can be feather-edged.

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    Features & Benefits

    • Areas of use:
      • For floors subject to vibration, movement, or impact
      • Damaged steps
      • Worn floors
      • Holed floors
      • Fitting guide rails
      • Different levels
      • Spalled expansion joints
    • Virtually indestructible epoxy resin floor repairs
    • Exceptional impact and wear resistance
    • Resistant to vibration
    • May be feather edged
    • Fast curing
    • Chemical resistant and anti-slip
    • Use internally or externally – it will not be damaged by frost
    • Impermeable and non-dusting
    • Can be painted if required

    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 Flex 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 Flex 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.


    Wear protective gloves.

    The resin and the sand are already pre-blended and is supplied with bottles of curing agent, 4 x 100ml.

    The curing agent is added to the sand/resin at point of use, and once mixed the mortar should be used within 15 - 30 minutes depending upon temperature.

    If the entire pack of Watco Concrex Flex cannot be used within 30 minutes, it can be part mixed. To split a pack carefully halve the sand/resin (ideally measured by weight), and use half the number of curing agent bottles. 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 thoroughly until the liquid is a uniform grey.

    Form the sand/resin into a mound and leave a small hole in the middle. Empty the curing agent into the hole, ensuring the bottles are 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 Flex is normally applied at 5mm - 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 Concrex Deep Fill which can be applied at 15mm - 100mm thick in one layer.


    Please contact us regarding applications not described here.

    Do not apply to wet surfaces.

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

    Product Details

    Data sheet

    For Use By
    Consumer Use
    Interior / Exterior Use
    Interior & Exterior
    For Use On
    Metallic Substrates
    For Use On
    Application Method
    Steel float or trowel
    Single, Two or Three Pack
    Pack Size
    Approximately 1.2m² per 10kg at 5mm thick.
    Recommended Thinner/Cleaner
    Equipment used for mixing and applying should be wiped clean with white spirit or a similar solvent before the Concrex® Flex cures
    Compatible Primers
    Not usually – see section headed ‘Priming’
    UN Number (Base)
    Layer Thickness
    Up to 50mm for hole filling only. Do not use at more than 15mm for screeding.
    Resistance to chemicals
    Citric Acid
    Resistance to chemicals
    Resistance to chemicals
    Resistance to chemicals
    Hydrochloric acid
    Resistance to chemicals
    Sulphuric Acid
    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
    Pot Life
    30-60 minutes depending on temperature.
    If Concrex Flex is used past its working life, trowelling will become difficult and adhesion will be reduced.
    Fully Cured
    Normally 3 - 6 hours depending on temperature.
    Curing time will be extended by low temperatures.
    Curing will be very slow or even arrested by temperatures at 10°C and below.
    Suitable For Use On
    Sand and Cement
    Suitable For Use On
    Suitable For Use On
    Concrete Floors
    Suitable For Use On
    Application Method
    Product Type
    Product Range
    Product Range
    Watco Specialist
    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.

    questions Graham Bodle on 2023-04-07 06:47:00

    Can this product be used outside ?

    Answer from Rawlins’ Technical Team: 

    Yes this produt can be used internally or externally.

    Question about the product

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    Watco Concrex Flex Epoxy Resin 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

    Film Thickness
    Total area²
    Or enter length and width dimensions:

    *All estimates are based on theoretical consumption rates for a single coat and do not take into account any substrate deviations or wastage


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