Surface Prep: Wall & All

Surface Preparation Guide for Wall & All

Ensure that surfaces are dry, sound, and free from dust, dirt, grease and oil before painting.

Plascon Wall & All Premium1. New Work:

1.1 Cement plaster, concrete and unglazed brickwork: Ensure that concrete has dried for at least four weeks and other masonry surfaces two weeks before painting. Remove any loose particles and laitance by most suitable means. Remove any oil, grease and mould release agents with PLASCON AQUASOLV DEGREASER. Rinse thoroughly. N.B. Soft, underbound, friable and highly porous surfaces must be restored to a sound condition with PLASCON MULTI-SURFACE PRIMER or PLASCON PLASTER PRIMER.

1.2 Fibre-cement: Remove any loose particles and laitance by most suitable means. Apply 1 coat of PLASCON BONDING LIQUID. Allow to dry for 16 hours. N.B. BONDING LIQUID must be overcoated within 3 days after application.

1.3 Gypsum plaster (e.g. Rhinolite, Cretestone): Apply one coat of PLASCON PLASTER PRIMER. If a gypsum plaster has been used as the joint skimming filler on gypsum board or dry wall partitioning, then these areas must be sealed with PLASCON PLASTER PRIMER.

1.4 Wood: Sand smooth with 150 grit paper working in the direction of the grain. Dust off. Seal knots and resinous areas with PLASCON KNOT SEAL. Prime exterior wood with PLASCON WOOD PRIMER.

1.5 Mild steel: Degrease with PLASCON AQUASOLV DEGREASER. Rinse thoroughly with water. Remove any rust by coarse sanding, mechanical grinding, etc. or PLASCON RUST REMOVER. Prime general surfaces the same day with PLASCON METAL PRIMER or PLASCOSAFE 18 PRIMER – use ZINC PHOSPHATE PRIMER RED OXIDE for structural steelwork.

1.6 Galvanised steel: Clean with PLASCON GALVANISED IRON CLEANER to achieve a water break-free surface. Rinse thoroughly with water. Prime the same day with PLASCON GALVANISED IRON PRIMER.

1.7 PVC gutters and down pipes: Clean and sand lightly. Prime with PLASCON PLASTER PRIMER or PLASCON MULTI SURFACE PRIMER.

2. Previously Painted Surfaces:

2.1 Previously painted surfaces in good condition: Remove loose and flaking paint back to a sound substrate and a firm edge by scraping and sanding. Spot prime bare areas with appropriate primer. Clean with POLYCELL SUGAR SOAP POWDER solution to remove all contaminants and chalked material. Rinse with clean water to remove all traces of SUGAR SOAP. Alternatively, clean with high pressure water jet. Sand glossy enamel surfaces to a matt finish to aid adhesion.

2.2 Chalky surfaces: Remove completely by scraping, wire brushing, sandpapering, etc. to expose the underlying substrate. Apply PLASCON BONDING LIQUID or PLASCON PLASTER PRIMER. N.B. BONDING LIQUID must be allowed to dry for 16 hrs and overcoated within 3 days after application.

2.3 Previously painted surfaces in poor condition: Completely remove paint by most appropriate means or by stripping with REMOVALL ALL PURPOSE COATINGS REMOVER. Treat as for new work.

3. Filling:

Fill defects with POLYCELL POLYFILLA MENDALL 90, POLYFILLA INTERIOR or EXTERIOR as appropriate. Seal POLYFILLA EXTERIOR with PLASCON PLASTER PRIMER. Fill wood with POLYCELL POLYFILLA MENDALL 90 and seal with PLASCON PLASTER PRIMER.

>> Download the Wall & All Data Sheet <<

26 thoughts on “Surface Prep: Wall & All

  1. I would like to know if kitchen tiles can be coated with plascon paints. If they can, which products should you use?

    • Hi Mark, thank you for your query.

      Please note that Plascon Kitchens & Bathrooms paint is suitable for wall tiles. However, we do not recommend that floor tiles be painted with DIY products.

      If you are wanting to paint wall tiles, you first need to prime the tiles with Tile and Melamine Primer. Please keep in mind that the Tile & Melamine Primer should be used as a primer before you apply any topcoat.

      It can only be used on Ceramic and Melamine. It is not recommended for floors, kitchen work surfaces and glass mosaics.

      Allow the first coat to dry thoroughly, then sand lightly with a fine paper and wipe clean before applying the second coat. Sand the primed surface lightly before application of the topcoat.

      Please see our Kitchens & Bathrooms Surface Preparation Guide for more info.

    • Hi Joey, it’s important to firstly determine why the paint is flaking. This could be caused by damp and the migration of salts, or the exclusion of Plaster primer or the use of low quality paint.

      Bonding liquid can be applied directly to the area, and once dry, (6 to 8 hours), I would then apply Polycell Fine Crack Filler as a skimming plaster. Once cured and set, apply a good quality paint to the entire surface. More on curing flaking can be found on our Common Problems page.

    • Hi Garry, sorry it has taken so long to get back to you. We have actually been asking technical to re-evaluate the best approach to painting precast walls, so we thank you for that!

      The issue is that a precast wall has many influencing factors, such as rising damp due to the cement nature of the product. It’s important to know if you plan to paint both sides of the vibacrete or only one? Many people use Nuroof to successfully paint vibacrete walls. However we do not recommend that Plaster Primer be used, as it would be ineffective if the other side is not painted. Plaster Primer is not only for adhesion but to offer alkali resistance. Once the surface is damp, Plaster primer offers very little alkali resistance.

      Because of the nature of the surface, (cement and constant absorption of moisture through the vibacrete) we need a topcoat that offers excellent breathability. If the wall is unpainted on the one side there is breathability, but if it is painted, then a lower quality product should be used to allow more breathing.

      Plascon Wall & All or Micatex are advised for the exterior surface of new precast concrete.

  2. If walls have been rhinolited and sealed with interior primer plaster liquid (unpigmented) can we still paint over with Earthcote / Earthcoat Sateen?

    • Hi Andy, thanks for getting in touch.

      Our technical team asks if you could please provide us with the exact name and product code of the product used as a primer? Once we know this we will be able to advise you.

  3. Hi. My flat has serious dampness on walls due to neglect on the outside. I cannot do the outside, but is it fine to just treat the inside and paint?

    • Hi Nish, thank you for your query.

      Where damp areas begin on interior walls due to exterior walls being in a poor condition, repairing and repainting just the interior will be futile as the problem will persist and travel elsewhere creating a larger damp area. The exterior surface will need to be repaired first once the source of the damp has been identified. Please see the following guides regarding Plascon Dampseal:

      1. Curing Rising Damp DIY Guide
      2. Curing Damp Walls with Plascon Dampseal

  4. Hi, I need some advice on how to tile over a shower wall that was previously rhinolited. I have removed most of the rhinolite plaster but have not got to the bare cement surface…. A mission of note. Secondly, the rest of the bathroom which is rhinolited and sealed and in good condition needs to be painted. What would the procedure be if I do not want to take the plaster off. Your advice would be greatly appreciated. Kind regards Greg

    • Hi Greg, thanks for getting in touch.

      1. For rhinolite surfaces, ensure the surface is clean, sound and dry.
      2. Apply 1 coat of Plascon Plaster Primer – allowing 16 hours drying time.
      3. Finish off with 2 coats of Plascon Kitchen and Bathrooms or Velvaglo Water-based – allowing 4 hours drying time between coats.

  5. Hi, I recently bought a place with walls that have a chipped effect on them. It basically looks like nails have been run through the plaster before it dried. I would like to change this so that the walls are smooth.

    What is the most economical way of doing this and whist are the products that need to be used?

    • Hi Kathleen, Polycell Polyfilla Mendall 90 is what you need! Please see the data sheet (linked here) for our product designed for filling cracks and holes in and around plaster, wood, brick, stone, concrete, stucco, metal, glass, fibre-cement and other masonry surfaces. Please refer to surface preparation, application and caution.

  6. Hi There.

    We Want to paint our outside walls and would please like to know which products we need to buy?

    Half the walls are raw cement bricks (Of which the outside facing the street has been painted before we moved in) and the other half is raw vibracrete walls on our and the neighbours’ side unpainted).

    I’d like to paint the brick walls the same light egg yellowish colour as the rest of our outside walls – were also painted when we moved in and we have never painted it since. And I want to make a kiddies colourful mural on the vibracrete wall.

    Can you please let me know which products I will need or which paint to use for what (primer, actual paint, sealer?) and what to keep in mind about painting over the mural in 10 years time when its withered and my daughter is approaching her teens and does not like murals anymore!

    Thank you very much!

    Kind regards
    Heike

    • Hi Heike, thanks for getting in touch.

      Please note that we do not have a paint specification for painting raw cement bricks. With regards to the vibracrete wall, if it’s unpainted you need to ensure that is clean sound and dry, apply one coat of Plascon Plaster Primer, allow it to dry for 16 hours and then finish with two coats of Plascon Wall & All – a multi-surface exterior paint with suede sheen finish and superior durability which keeps walls looking beautiful for years and has unique dirt barrier formulated to protect against dirt and inhibit mould growth.

  7. I have started preparing my exterior walls for painting. It has not been painted for 15 years. I have stripped most areas down to the plaster. In most areas the plaster is quite stable and strong. Do I need apply a plaster primer to these areas first? Can I do any harm by priming in any case?

    In other areas the plaster mix is very “sandy” and I intend applying bonding liquid there – worked quite well elsewhere? Does this sound right? Does the bonding liquid serve as a primer as well, i.e. does the application of the bonding liquid take away the requirement prime? In some places I cannot get off all the paint – can I do harm by applying the primer over he paint? In some areas I had to damp seal as well and am concerned about where I applied it over the paint as well – higher up where the damp problem did not really exist. Your assistance has been of great help in the past.

    • Hi Les, thanks for coming back to us. Here’s what you need to do:

      1. Wash the walls with a Polycell Sugar Soap Powder Solution.

      2. Rinse with clean water to remove traces of the sugar soap and allow surface to dry completely before painting.

      3. Spot prime all bare plaster with Plascon Plaster Primer allowing it 16 hours to dry.

      In areas where the plaster is sandy, make sure that the plaster is restored to a sound surface if not sound. For loose and friable surfaces remove all loose and flaking paint. Thoroughly brush down chalked and powdery paint. Remove as much of sand/powdery residue as possible, scrubbing with a stiff bristle brush (or wire brush on masonry) and then rinse thoroughly; or use sugar soap powder solution, rinse with fresh clean water and allow surface do dry, then prime with Plascon Bonding Liquid – allowing it 16 hours to dry and finishing with two coats of your choosen topcoat.

      Kindly note that one cannot apply a primer over a paint, primer goes on bare plaster.

  8. Hi. Several questions::
    1. Can you skim with gypsum plaster over a wall treated with damp seal ?
    2. Can I paint over damp seal – if so what paint should I use?
    2. Can you paint over a wall treated with wall seal – what paint can I use?
    3. Can you tile over damp seal or wall seal with porcelain tiles?

    Thanks
    Lisa

    • Hi Lisa, thank you for your queries.

      1. No you cannot / should not apply gypsum plaster over Dampseal.
      2. Dampseal can be over-coated with any Plascon water- or oil-based paint.
      3. Wallseal is a top coat which can be tinted to any colour of your choice.
      4. You cannot apply tiles over Dampseal or Wallseal.

      It sounds like you may be wanting to do a full waterproofing system on your walls? Please note that Dampseal should only be used for rising / penetrating damp not more than 1.1m above ground level.

      If you are looking for a full waterproofing system, we can recommend a company called Coprox who can be contacted on 011 579 4300.

  9. Hi there, most of my interior walls are plastered with cretestone. The cretestone is sealed (covered by a glossy transparent layer). Do you have a primer that can be painted over the cretestone sealer or would I need to sand my walls first and then paint on the primer?

    • Hi Kobus, thank you for getting in touch. Kobus we recommend first removing the cretestone sealer, as we do not know what type of sealer it is. The adherence of the Primer might not be that good if applied directly onto the sealer.

  10. How long can you leave POLYCELL POLYFILLA MENDALL 90 on an exterior wall for before over coating it with Plaster Primer? I could not finish the filing, sanding and priming in one weekend.

    • Hi Peter, thanks for connecting. Please note that although it may be left unpainted, it should not be exposed to permanently wet conditions. It is therefore advisable to overcoat POLYCELL POLYFILLA MENDALL 90 with PLASCON PLASTER PRIMER.

  11. I want to install glass mosaic backsplash in my kitchen. The previous ceramic tiles came off easily but the tile adhesive is pretty much stuck to the wall. It is some type of cement or plaster-based product. Can I tile the mosaic glass tile over this? What is best way to prepare the surface?

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