Mapei Primer G is a water-based synthetic resin primer for treating gypsum or anhydrite substrates prior to installing ceramic tiles or stone material with cementitious adhesives. Primer G has very low emissions of VOC. For general dust suppression and reducing the absorption of very porous substrates. Suitable for use on absorbent substrates only e.g. screed, plasterboard, plywood.

Key Features

• Easy to apply with brush or roller
• Very low VOC
• Water based
• Drying time 2 hours

Surface Preparation
The substrate must be clean, dry and free from oils, grease, laitance, residual paint and other loose material. In each case, the manufacturer's recommendations for gypsum-plaster must be followed, particularly as far as moisture content and level of surface finishing are concerned. Cracks in concrete surfaces must be repaired with Eporip or Epojet. Anhydrite surfaces must be mechanically abraded.

Recommended Systems
As a treatment for ceramic tiles installed on gypsum: Stir the Primer G just before use, spread it uniformly on the surface with a flat brush without diluting it. If the gypsum plaster surface is especially smooth and glossy, it is recommended to abrade it beforehand. Once it has dried fix the tiles.
As an anchoring coat for gypsum plasters: Dilute Primer G 1:2 with water and stir well; spread the mix on the surface with a flat brush or spray pump. Apply the sprayable gypsum as soon as Primer G is dry.
As a primer before applying self-levelling compounds and thixotropic smoothing compounds from the MAPEI range on: cementitious substrates: dilute Primer G 1:1 or 1:3 with water (depending on the absorption of the substrate); ceramic, marble and non absorbent substrates: dilute Primer G 1:1 with water; gypsum based substrate: use Primer G neat. As a primer for wallpaper adhesives: dilute Primer G 1:3 with water.
As a primer between smoothing layers: dilute Primer G 1:3 with water.

Consumption
The consumption of Primer G depends on the porosity and absorption of the surface. Normal consumption is between 0.1 and 0.2kg/m².

Technical Characteristics
Primer G is a water dispersion of special synthetic resins which, once applied to any surface, dry to form a flexible, compact, shiny coating which consolidates the surface, where needed. Primer G also improves the adhesion of smoothing compounds, paint, adhesive for wall paper, adhesive for tiles and mortar for renders. The film of Primer G on the surface of gypsum or cement, prevents any chemical reaction between sulphates and the cement aluminates of the tile adhesive which, in the presence of moisture, leads to the formation of the salt ''ettringite'' which is the cause of tiles breaking away from gypsum substrates. Primer G makes wallpaper stripping far easier and decreases the amount of glue used for paperhanging. When used before applying sprayable plasters, Primer G prevents over-rapid absorption of water by the substrate, prolongs finishing time and helps prevent shrinkage cracks. When used before the application of self-levelling compounds, Primer G reduces the formation of air bubbles and helps prevent over-rapid drying making self-levelling easier. Primer G is not inflammable and can therefore also be used in closed, unventilated environments without any precautions having to be taken.