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How to use a waterbased cementitious primer

Before we learn how to use a primer, we first need to understand what it is and where it fits into our range of cementitious polymers, i.e. polymers that are designed to go into concrete, under concrete coatings, and as sealers for concrete coatings.

Our specialty is decorative concrete resurfacing, therefore, to get good adhesion to the substrate prior to applying a resurfacing coating, we use a styrene-acrylic polymer as a primer. This is good as it not only is a stronger primer that locks into the substrate, but it also helps to prevent moisture or rising damp  from coming up through the slab and creating the hydrostatic pressure to delaminate the coating.

The key to any coating solution is surface preparation, therefore, using a product that is designed for stronger adhesion and moisture blocking is just common sense.

So what is Y863 Primer? It is a very high-strength styrene acrylic binder that is used to strengthen and waterproof concrete and cement-based pavers, blocks and renders. When used as a superplasticiser admix it will increase cure rates, and produce stronger, waterproof concrete.

It is also an ideal admix for the construction of pools and water features. However, waterproofing concrete has some important benefits beyond the obvious. By stopping the free passage of water through the concrete salt migration is also eliminated and problems such as efflorescence, reinforcing corrosion, delamination and rising damp are avoided.

Y863 Primer can also be used topically for stabilising and strengthening friable surfaces. If it is applied as a primer coat to newly rendered walls it will increase the strength and durability of an acrylic texture coat without the cost.

The high concentrations of acrylic polymer in Y863 Primer add flexibility and strength to cementitious materials and prevents dehydration from the effects of wind, sun and dry heat during the curing process.

Rendered walls primed with Y863 Primer have a significantly improved service life and provide the perfect base for exterior paints. Further, the primer also waterproofs the render so delamination of paint from negative hydrostatic pressure (i.e. rising damp) is less likely to occur. 

All our cementitious polymers are concentrated. They must be diluted with water at a 1:3 ratio before application. The fact that is it concentrated means we pass the savings to the customer and applicator. However, the applicator needs to adjust the ratio according to their system and reading all associated conditions.


  • A super-strong concrete binder and water reducer. 
  • Use as an admix to create super-strong and waterproof concrete.
  • Increases surface strength and water resistance of concrete when applied topically.
  • An excellent primer for spray-on decorative concrete finishes.
  • Apply directly onto new concrete for a rapid cure to save fresh slabs from rain damage.
  • Stabilises and strengthens friable surfaces.
  • Adds strength to render cement.
  • An excellent primer for rendered and plastered walls.
  • Very cost-effective method of increasing the quality of the render.
  • Non-Hazardous Material Classification.
  • Exterior paints friendly.

Technical details

Curing Time:

  • Touch dry: 30-60 minutes
  • Recoat: 24 hours
  • Fully cured: 72 hours

Coverage: 20-25m²/litre depending on surface porosity

Dilution: 1:3 (1 part product to 3 parts water).

Clean-up: Water

Equipment needed: Pump sprayer or WBS CSU (Commercial Spray Unit) and broom

Odour: None


  • For use as a water-based primer for resurfacing systems.
  • For use on newly constructed rendered walls to minimise the development of cement-associated surface cracking.
  • Use to bind and waterproof cement-based materials.


Dilution: Y863 Primer is a highly concentrated product that requires dilution with water before application. Mix the neat product thoroughly before dilution. Suggested dilution rates are 1:3.

Application: Diluted solution should be mixed thoroughly before application. Apply using a CSU (Commercial Spray Unit) or suitable spray applicator. Best applied to a wet/damp surface to help draw product into the surface material.

Use the white colour of the product as a visual aid to achieve even coverage. Use a soft bristle broom to sweep out any pools that develop. Allow to dry clear / 24 hours before applying paint.

Wash all equipment with water after use.

Environment and Safety

All of Barefoot Concrete’s water-based products are environmentally responsible. Y863 Primer is an environmentally friendly product that:

  • Water-based
  • Contains no petroleum solvents or silicone compounds
  • Non-hazardous and non-toxic
  • 100% biodegradable
  • VOC < 2 g/L

Store products in a cool dry area, and keep the product out of direct sunlight. Keep out of reach of children, wash up any spills by flushing with water, avoid contact with eyes and skin, for professional use only.

If you want to buy Y863 Primer, go to our shop and purchase online, here is the link.

Contact us at Barefoot Concrete to discuss your requirements. Mobile: 0490 960 185.