Casein Primer (250 g)

SKU: P-145-8 Category:


The primer is applied prior to the application of a paint or a plaster. A transparent primer, it is used to stabilize backgrounds and their absorption to ensure the proper rendering and durability of the chosen finish.


FormatConsumptionCAD $
250 gApprox. 660 ft²40.50

In stock




Casein primer is composed of milk protein.

The primer is applied prior to the application of a paint or a plaster. A transparent primer, it is used to stabilize backgrounds and their absorption to ensure the proper rendering and durability of the chosen finish. It is applied on untreated substrates such as plaster (lime, plaster, cement, or clay plaster), plasterboard, blank gypsum, limestone, and concrete. It is not suitable for smooth, non-absorbent, or permanently damp substrates. It can, in certain cases, be used to consolidate interior plasters (clay coating for example).

Packaged in powder form, it can be diluted with water and applied easily with a brush in transparent base coats.



When using the product, the complete product information must be observed.

TIPSHEET : How to apply casein primer



Suitable for all untreated surfaces, such as clay, lime or lime-cement plaster, gypsum or gypsum-cellulose boards, stone, concrete.

Recommended for renovations on existing, absorbent paints such as casein, clay or lime paints, as well as emulsion paints.

Not suitable for smooth, non-absorbent and/or permanently wet surfaces.

Can be used for solidifying slightly friable plasters, especially clay plasters, in interiors; prior testing is required (see the “Tips” section below).

The use of casein primer with Tockay paints and plasters is explained in each of the Technical Data Sheets for these products.



Facade brushes, ceiling brushes, natural silk lime brushes. Roller or spray gun are not suitable.



The surface must be absorbent, clean, dry, solid, degreased, and free of penetrating and coloring substances.

– Check for good adhesion of old paint

– Remove any paint in poor condition and any remaining wallpaper glue

– Carefully brush off powdery surfaces

– Clean and degrease untreated plaster

– Treat the coloring materials which can reappear by capillarity

– Remove mechanically the remains of binders on the plaster

– Remove all formwork oil residues from the concrete

– Remove crumbly, flimsy parts of the plaster, repair with the same type of plaster

– Clean mineral substrates covered with mould and treat them with an anti-mould product



To mix the casein primer, it is preferable to use a 10-litre bucket and a mixer (a drill equipped with a whisk). Pour the casein primer (250 g) into 2 litres of clean, cold water, stirring constantly. Stir well. Let stand for about 30 minutes, then mix again and dilute this mixture with an additional 6 litres of water.



Apply the casein primer evenly, saturating the substrate. Start by saturating joints and repairs made with plasters. Let dry and apply a coat on the entire surface, including joints and repairs.

Apply only as much liquid as can be absorbed by the surface. Remove excess (wet shiny spots) with a cloth before drying.

Minimum application temperature: 8°C.

The primer must be applied the same day as the preparation of the mixture. Never use a rotten or smelly primer, as this may cause a prolonged odor on the surface, even after drying.



Dry after about 8 hours, at a temperature around 20°C. The surface can then be covered with lime paint or plaster without any problem.



Clean with water immediately after use. If necessary, use Marseille soap.



The procedure for applying casein primer is the same for all plasters, whether lime, clay or any other coating without paint.  It is important, however, that the casein primer be completely absorbed by the plaster; otherwise, areas of gloss may remain visible.

Application should be from the bottom up, to avoid drips. The surface tone may darken slightly.

It is important to test the primer before applying it to the entire surface to assess the change in tone and to check for potential problems (white spots, efflorescence) in the plaster.


Technical Data


It should be noted that the yield may vary depending on the substrate, the application method and the quality of the surface. Determine exact consumption by testing.

Before using this product, consult its Technical Data Sheet