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Auro Plaster Primer 301
Auro Plaster Primer 301
Auro Plaster Primer 301

Auro Plaster Primer 301


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  • Product Overview
  • Technical Details
  • Downloads
  • Installation guide

Product Overview

Main purpose

A Breathable primer for highly absorbent new plaster, interior walls and ceilings

Use it on

Highly or irregularly absorbent mineral substrates such as Gypsum Plaster Board, Gypsum Fibre Board, any highly absorbent interior plaster.


The Auro Plaster Primer 301 is a breathable, water based primer suitable for highly absorbent interior plasters. It is made from natural ingredients from renewable and mineral sources. It is virtually VOC free, preservative free, and is diluted on a ratio of 1:1 with water. Unlike most conventional paints, this paint does not contain any synthetic ingredients or plastics and it is vegan friendly.

Where to use it

The Auro Plaster Primer 301 is a thin breathable primer for usage on high suction surfaces for example gypsum plaster board. It is for interior use only and it is available in 2 litres and 5 litres. It must be diluted with water at a ratio of 1:1. 

What it does

Some plasters are what can be described as ‘thirsty’ so they will drink the paint and the result will be multiple coats needed as the paint will be sucked into the plaster. The Auro Plaster Primer 301 provides a uniform surface for the paint to be applied to resulting in less coats of the paint as it is not sucked into the plaster. 

Some plasters are unevenly absorbent which can leave the paint looking patchy, so the Plaster primer stabilizes the wall for a uniform finish throughout.

All Auro Wall and Ceiling Paints can be used as a follow up treatment.

Why we love it

It is very economical as it saves a lot of time applying layer upon layer of paint on an absorbent surface. It has excellent coverage of 20sq/m per litre.

This Auro product is a vegan friendly and impressively it is fully compostable.

The VOC Level of the Plaster Primer is ≤ 1 g/l which makes it virtually VOC free

Auro Plaster Primer 301 is certified as "Allergy Friendly" from the German IUG (Institute for Environment and Health) because it has features which are favourable to people with allergies

All ingredients are of course fully natural and listed on the tin, you can easily see that there are no harmful ingredients which makes it a perfect choice for your home.

How it works

The Plaster Primer made from only natural ingredients is a milky appearance when applying but dries transparent. This is useful when applying as you can see the area which has been treated. It is diluted 1:1 with water (for example 5 litres of primer is diluted with 5 litres of water to make 10 litres). 

It will be dry and recoatable after 4 – 6 hours. Allow for plenty of ventilation during the drying period as high humidity, low temperatures and high application volume will result in prolonged drying times.

Hints and Tips

If you are unsure if the plaster is highly absorbent or not spray a small amount of water from a spray bottle onto the surface. If it is absorbed very quickly the plaster is 'thirsty' and the Plaster primer should be used.


  • Breathable Primer
  • AgBB Certified as class A+
  • Suitable for Allergy Sufferers
  • Transparency of Ingredients
  • Levels highly Absorbent Surfaces
  • Plastic Free Primer
  • Excellent Coverage
  • Vegan Friendly Product
  • Easy to Apply


  • Allows the walls to breathe
  • Reduces the risk of mould and damp
  • SD Value 0.1
  • VOC Free
  • Solvent Free
  • Water based
  • Low Emission
  • Does not contain any preservatives (MIT/BIT/Thiazoles)
  • Certified as ‘Suited for Allergy Sufferers’ by the Institute of Environment and Health in Germany
  • Compostable
  • Less Paint will be needed as the following coats will not be absorbed into the plaster
  • Will not trap moisture
  • Vegan Product
  • Brush, roll or Spray application
  • Good coverage 20sq/m per Litre
  • Overcoatable after 4 – 6 hours


How do I know if my plaster is very absorbent?

A quick test which can be done to see if the plaster is absorbent is, spray a small amount of water onto the surface and see if it is absorbed quickly, if it is, this primer should be used. If it is rather slow to absorb into the plaster then you do not need to use this primer.

Do you have to dilute this product?

Absolutely, it must be mixed 1:1 with water. For example if you have 100sq/m to cover, 5 litres of the plaster primer will need to be mixed with 5 litres of water to make 10 litres of primer. This is very cost effective way of priming your walls. 

Is this product suitable for allergy sufferers?

Yes, this is certified as 'suitable for allergy sufferers' 

This product was tested by the Institute for Environment and Health (IUG). After an extensive analysis, all submitted products were positively evaluated because no allergens were found and the binding agent used constitutes no risk to human health. As a result, the IUG institute authorised Auro to use the product label ''suitable for allergy sufferers”.

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Technical Details

Key Technical Data

Technical Datasheet

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Material Safety Datasheet (MSDS)

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  • Download

Installation Guide

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Like applying any paint, it is important that the plaster is fully dry before applying. Any filling that needs to be done can be done using the Auro Wall filler 329. Shake the contents well and dilute 1:1 with water (For example 5 litres of primer is mixed with 5 litres of water to make 10 Litres). It is recommended to be applied by brush or by spraying. It can also be applied by roller but it must be applied very thinly ensuring that it is fully absorbed into the substrate. Remove any surplus if needed. When the surface is fully dry (After 4 – 6 hours) the wall can then be coated using Auro Wall Paints.

Tools can then be cleaned using water and if necessary, some Auro Plant Soap 411 may be used.

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