Eco-compatible, certified, aqueous insulating preparation for mineral, dry absorbent substrates based on cement, plaster and anhydrite, ideal in GreenBuilding. One-component, with the lowest emission of volatile organic compounds. Environmentally friendly and health user in Primer A Eco creates a bonding insulation coating, suitable for neutralizing the expansive chemical reaction of gypsum and anhydrite based substrates in contact with mortars and mineral adhesives. Reduces and regulates the absorbency of high porosity substrates.