EWI-226 Aquabase – 25kg

£27.48 (incl VAT)

In stock

  • Water resistant basecoat
  • Vapour permeable
  • Strong adhesion
  • UV-resistant
  • Ideal for wetrooms, bathrooms and below DPC
  • Internal/external use

EWI-226 Aquabase Water Resistant Basecoat

EWI-226 Aquabase is our most waterproof basecoat adhesive, suitable for use in areas where there is a high risk of water ingress. Durable and vapour permeable, the product is suitable for fixing polystyrene insulation boards (such as XPS) onto external substrates; this product is highly recommended for when rendering or insulating below the DPC. The basecoat can also be used in bathrooms for around showers/baths, and in wet rooms. It is not intended for use in swimming pools. 

EWI-226 Aquabase can be used for two purposes:

  • An adhesive used to create the reinforcement basecoat layer in render only or EWI systems
  • An adhesive used to fix polystyrene insulation to a substrate.


EWI-226 is prepared in the same way regardless of whether it is being used as a basecoat or an adhesive for fixing the insulation boards to the substrate. Aquabase comes as a dry mix in 25kg so needs to be mixed with clean, cold water (5-6 litres) prior to use. We suggest filling a large bucket with the correct quantities of water prior to adding the dry basecoat mixture. Once the basecoat has been added to the water, it needs to be mixed using a paddle mix until an even consistency mortar is produced. Once the product has been mixed sufficiently, leave the bucket for 5-10 minutes and then remix using the paddle mix before the adhesive is ready for use.


If using Aquabase for the basecoat layer, apply the basecoat using a 10mm notched trowel to the substrate. Then embed overlapping pieces of Fibreglass Mesh – the mesh should sit within the middle of the basecoat layer. Another layer of the product should be applied on top of the mesh to ensure water tightness. The basecoat layer should be 5mm in total.

If using Aquabase to fix insulation to the substrate, the basecoat can either be applied to the whole surface of the insulation board using a notched trowel or applied to the perimeter of the insulation board with 3 dabs across the middle.

Application Conditions:

  • Primer: EWI-301 or EWI-310 if a key is required
  • Application temperature (air, substrate, materials): from +5°C to 25°C
  • Time of usability after mixing with water: approx. 2 hours (temp. +20°C)
  • Water mix proportions: approx. 5-6 litres of water per 25 kg of dry mix
  • Quantity to be used: approx. 4-5 kg/m2

Storage Conditions 

Comes in powder form in a 25kg paper bag.

Store in a cool, dry place. Avoid ingress of water. Shelf life: up to 12 months from the date of manufacture.

SKU: EWI-226


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