Drybase Liquid-Applied DPM

Application

Application For Drybase Liquid-Applied DPM

Preparation

Proper preparation of the background substrate is essential to ensure product performance. All contact surfaces must be sound, clean and smooth with a trowelled or brushed finish. Any masonry should be flushpointed and defects in existing surfaces made good. Remove all laitance, dust, dirt, grease, paint, old coatings, loose material or surface water. For new screed and concrete, allow sufficient time for the substrate to cure before applying Drybase Liquid-Applied DPM – at least 28 days.

Priming

Sound Surfaces

For sound surfaces no priming is necessary. To assist the membrane in fully wetting out the substrate the background should be dampened with clean water. There should not be any standing water.

Weak, Friable Surfaces

For surfaces with laitance and loose material there are two options to prime the surface before Drybase Liquid-Applied DPM application:

Option 1 – Remove the weak top surface by scabbling the floor and sweeping/vacuuming up all dust and loose material. Apply 2 coats of Drybase Liquid-Applied DPM.

Option 2 – Remove all dust, previous coatings and loose material by sweeping/vacuuming. For the best adhesion apply a coat of Drybase Bondaid Plus (SBR) to the surface as a primer and wait 20 minutes, or until tacky before applying 2 coats of Drybase Liquid-Applied DPM. Alternatively, if Bondaid Plus is not available then dilute the first coat of Drybase Liquid- Applied DPM with 30% water for use as a primer. Maximum bond can be achieved by vigorously brushing the primer coat into the floor substrate using a stiff bristled broom. Once dry, apply two coats of Drybase Liquid-Applied DPM as normal.

Test Area

Because of the wide variety of possible substrates and site conditions, it is always advisable to check adhesion to the background by testing on a sample area before starting any job. Limitation: Do not directly bond wooden flooring to Drybase Liquid-Applied DPM coated concrete.

Application

Coating and Coverage

The product is applied in two coats by brush, roller or airless spray. Stir well before use. Care should be taken to ensure that the correct dry coat application thickness is achieved and that the drying time is not unacceptably extended. Drying will be delayed by excessively damp, humid or cold conditions which should be avoided.

A minimum dry film thickness of 0.6 mm (1.1 mm wet film) is required to provide a vapour barrier. This should be applied in at least two coats with each at 0.55 litres/m2 in order to comply with CP102:1973 – Code of Practice for the Protection of Buildings against Water from the Ground. Always allow the first coat to become touch dry (typically one hour) before applying a second coat at right angles to the first. The first coat should not be allowed to dry for more than 24 hours before applying the second coat. Care should be taken to ensure Drybase Liquid-Applied DPM is not too thickly applied, as in line with other paint coatings, over-thick application can lead to surface cracking through uneven drying.

If applying a subsequent screed to Drybase Liquid-Applied DPM, the second coat may be used as a primer for the screed, and should be applied while the second coat is still tacky. Alternatively the surface of the last coat of Drybase Liquid-Applied DPM can be blinded with clean sharp sand to provide some mechanical key to the subsequent screed.

Curing

No special curing is required. Do not apply if the background or air temperature is 7 °C or lower. Ensure there is adequate ventilation for drying. Black Drybase Liquid-Applied DPM will go on as dark blue and dry to black once cured. If the colour remains blue then this is an indication that further drying is required.

Limitations

Drybase Liquid-Applied DPM is not intended as a trafficable surface and should not be used where it will be externally exposed to direct sunlight.

Not suitable for use in situations under negative water pressure such as basements and other below ground situations. Here, Drybase Tanking Slurry is recommended.