Surface Prep: Plascon Roofseal

Surface Preparation Guide for Plascon Roofseal

Surface Preparation Guide for Plascon RoofsealEnsure that surfaces are dry, free from dirt, grease and oil and loose and flaking paint. Remove any fungi and algae with household bleach (3,5 % sodium hypochlorite solution) and rinse thoroughly with water.

1. Porous Cement Plaster, Concrete, Fibre-Cement & Other Masonry Surfaces:

Open any cracks (other than hairline cracks) into a V-shape and remove dust. Apply one coat of PLASCON PLASTER PRIMER (UC 56). Fill cracks and other defects with MENDALL 90 ALL PURPOSE ADHESIVE FILLER.

2. Cement Roof Tiles:

Remove loose and flaking material back to a sound substrate. No further
priming necessary.

3. New or Weathered Galvanised Iron:

  • Clean with GALVANISED IRON CLEANER and rinse thoroughly with water to achieve a water break-free surface. Remove any red rust with scouring pads or sanding back to bright metal.
  • Spot prime areas where rust has been removed with PLASCOSAFE 18 PRIMER – see Product Data Sheet for application details.
  • Prime the entire surface with PLASCOSAFE 18 PRIMER (EMS 18) or GALVANISED IRON PRIMER.

4. Mild Steel:

  • Degrease with AQUASOLV DEGREASER and rinse thoroughly with water.
  • Remove any rust by coarse sanding, mechanical grinding or with RUST REMOVER.
  • Prime surfaces with MULTI-SURFACE PRIMER. N.B.: Millscale must be removed by abrasive blasting or mechanical grinding before coating.

5. Previously Painted Surfaces in Good Condition:

  • Remove any loose and flaking paint, clean and spot prime bare areas with the appropriate primer.
  • Clean paintwork with POLYCELL SUGAR SOAP POWDER CLEANER and rinse thoroughly.
  • Alternatively, clean with high pressure water jet. Sand glossy paint areas to a matt finish.

>> Download the Plascon Roofseal Data Sheet <<

2 thoughts on “Surface Prep: Plascon Roofseal

  1. I wish to DIY paint/seal a flat fibre-cement 4mm (2.4mx1.2m) sheet, currently being used as a window shade, to make it more water-resistant… How should I dilute ROOFSEAL WRS4 to make it suitable for application by hand and with brush? If possible, I intend to paint in slightly over-lapping strips, allowing each strip to dry, before applying the next. I await your guidance.

    • Hi Stella, thanks for getting in touch with us. Here’s what you need to do.

      If you are using without the membrane then: Apply Plascon Roofseal (untinned) at an average spreading rate of 4 – 5 m²/? per coat. Allow at least two hours drying between coats.

      With the Membrane (for waterproofing and crack sealing with membrane): For porous surfaces thin first coat 1:1 with water to aid penetration and adhesion. Allow to dry for 2 hours.

      To all primed and sealed surfaces, apply a full coat of Plascon Roofseal (untinned) at approximately 2 m²/?. Immediately embed the polyester membrane into the wet coating – ensuring that the membrane is thoroughly saturated by the coating.

      Before this coat is completely dry apply a further coat of Plascon Roofseal to completely cover the membrane. Allow to dry and finish with a final coat of Plascon Roofseal.

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