Previously sealed concrete surfaces
A cross hatch test is required if the surface has been sealed more than 2 years ago to ascertain whether existing sealer is suitable to be resealed over.

1. Use a sharp blade to create a light “crosshatch” incision through the sealer.
2. Place a piece of self adhesive tape (suggest clear packing tape) over the incision.
3. Press firmly for maximum adhesion and remove sharply. Repeat with fresh tape several times. If sealer is present on the tape, it is advised the sealer be completely stripped from surface. Seek professional contractors should stripping be required. If there is no sign of sealer adhering to the tape or delaminating from the surface, this would indicate that the bond of the existing sealer is sufficient for resealing.

Important note: if current sealer shows signs of whitening or blooming, regardless of cross hatch test results, sealer may need to be stripped completely from the surface. Whitening may reoccur if new coat of sealer is applied over this problem.

Cleaning
Concrete is to be clean and free of grease, oil and any other contaminants. A stiff broom and general purpose cleaner are recommended. Pressure clean at minimum 2000 psi to clean and remove all contaminants. Allow surface to dry before resealing (sealing over damp concrete will cause whitening). Solvent Treatment If the existing sealer on the surface is surface is more than 2 years old, Solvent is required to reactivate the existing sealer. This will help with the adhesion of the new sealer coat. Apply Dulux Avista Solvent to the area being resealed using a roller and roller tray or broom. Note: If resealing a resurfaced area, Do not apply too much Solvent as it may soften the resurfacing product. Complete solvent treatment of entire surface. Allow area to dry enough to walk on before proceeding with sealer application.

Preparation Instructions for New Cured and Old Concrete (unsealed)

Ensure concrete is sufficiently cured (recommended minimum 14 days).
Concrete is to be clean and free of grease, oil, paint or any curing agent. Stiff broom and general purpose cleaner recommended. Any oil stains should be treated & cleaned with an industrial degreaser.
Pressure clean surface at minimum 2000 psi and allow to dry.
Acid etch with hydrochloric acid. Dilute approximately 20 parts water to 1 part acid (depending on porosity) to remove any loosely bound cement and laitence.
Note: smooth concrete will require a higher acid content. Maximum strength - 10 parts water to 1 part acid.
Apply diluted acid to surface using a large head watering can, applying in a criss cross motion (approximately 5-10m² sections). Acid will start to fizz on the surface once it starts to react with the laitence in the concrete. Pressure clean immediately to clean and remove all remnants of acid (do not allow acid to dry on surface). Pressure clean at minimum 2000 psi. Allow surface to dry before sealing (sealing over damp concrete will cause whitening).

Application Methods
Sealer to be applied by a suitable solvent resistant broom or 11mm-22mm nap roller. Roller used will depend on the profile of the concrete.
The sealer must be mixed prior to application using a stirrer or paddle.
To apply sealer, pour sealer into a roller tray, and evenly roll or broom onto the surface.
Ensure sealer is not applied too thick and no pooling occurs as this may cause bubbling.
Avoid excess sealer build up on the edges of the roller. This can lead to roller lines in the surface.
An additional coat of sealer can be applied after a minimum of 2 hours, (recommended recoat 2 hours)

Drying time: Minimum of 2 hours between coats when applied at 25°C and above at 50% relative humidity. Recoat times will be longer in cooler weather (<25°C) or higher humidity. Do not apply sealer at temperatures below 8°C or above 35°C. To obtain a lower slip factor it is advisable to use the appropriate Slip Reducing Additive with the sealer for better grip under adverse conditions e.g. wet areas, steep slopes and pool surround areas.><25°C) or higher humidity.
Do not apply sealer at temperatures below 8°C or above 35°C.
To obtain a lower slip factor it is advisable to use the appropriate Slip Reducing Additive with the sealer for better grip under adverse conditions e.g. wet areas, steep slopes and pool surround areas.