Wall Primer Paint Options from Celtic Sustainables

We offer a variety of wall primer paints tailored to different needs. Whether you're preparing a room for a fresh coat of paint or tackling problematic surfaces, choosing the right primer ensures your paint job lasts

Wall primer paints are an essential step in achieving a flawless and durable paint finish on your walls. They help to seal porous surfaces, improve adhesion of the topcoat, and can even prevent issues like staining or peeling over time.

When and Why you need a Primer

Knowing when to use a primer is crucial for the success of your painting project. Generally, primers are recommended:

• When painting over bare drywall, plaster, or new wall surfaces.
• To block stains or watermarks.
• When switching from a dark to a lighter colour.
• On glossy or uneven surfaces to create a uniform base.
• The surface is porous

When preparing your surfaces for painting, choosing the right primer is an important step to ensure a smooth, long-lasting finish. Here's some helpful information to guide you:

When painting over bare drywall, plaster, or new wall surfaces.

In this instance, you need a primer to seal the surface. Primers prevent paint from being absorbed unevenly, which can lead to a patchy, uneven finish and require more paint coats. Primers also improve paint adhesion, ensuring a durable, long-lasting finish.

Paint Primer for Interior Walls:

For internal walls, Earthborn wall glaze is very good at stabilising porous or chalky lime plaster whilst keeping the lime breathable. Another option for lime or gypsum plaster is Graphenstone Naturcolor. We agree it’s a good all-round primer paint that must be diluted to achieve a mist coat and primer for new plaster and lime. It's a good price and goes a long way, and it’s a natural, environmentally friendly option.

If you're using Earthborn Claypaint and Lifestyle emulsion on bare gypsum plaster, for best results, you can dilute the first coat of paint with around 20% water to 80% paint, followed by a full coat of paint.

Another popular plaster primer option from Auro is the 301 Natural Plaster Primer, which is low-odour, solvent-free, preservative-free, and designed for durability while being suitable for people with allergies or MI sensitivities. It is highly effective, breathable, and offers excellent coverage. To use, dilute it with water, and the milky substance can be applied using a brush or roller.

Paint Primer for External Walls:

Why do you need a primer for external walls? We generally recommend using the manufacturer's primer for two main reasons: first, because it guarantees compatibility within the entire paint system, ensuring the topcoat adheres properly; second, because external walls in the UK face extreme weather conditions – including frost, heavy rain, and heat waves- which your render paint must withstand. Therefore, you want a primer that is flexible, durable, UV stable, and often breathable.

It improves adhesion by forming a strong chemical bond between the primer and the substrate, as well as between the primer and the silicate paint, preventing peeling or flaking.

Additionally, a silicate primer is essential for silicate-based masonry paints to ensure proper adhesion and durability. It stabilises porous or loose surfaces, allowing the paint to bond chemically and create a long-lasting, breathable finish. 

WHEN TO APPLY AN EXTERNAL PRIMER

• For bare, porous mineral surfaces using silicate masonry paint
• When the surface is loose, powdery, or absorbent
• To achieve a durable, breathable, and weather-resistant finish. 

The different paint primers from Celtic Sustainables:

• Earthborn - Silicate Primer Ideal for mineral surfaces, offering durability and breathability. This liquid primer is suitable for use before applying Silicate Masonry Paint and can be used as a primer for absorbent surfaces. Available in 2.5 litres and 5 litres.
• Earthborn - Bonding Primer Great for improving adhesion on difficult surfaces. The Bonding Primer from Earthborn allows you to use the Earthborn Silicate Masonry Paint on previously painted exterior surfaces!
• Graphenstone - Ambient Primer L42 Suitable for overall wall preparation. Graphenstone Primer L42 is a mineral primer with graphene technology designed to increase the durability of photocatalytic paints.
• Beeck Fixative mineral primer is designed for porous mineral surfaces like lime plaster, lime render, stone, and brick, preparing them for painting with Beeck Mineral paints such as Maxil Pro (interior) and Renosil Fine (exterior).
• It also acts as a stabiliser for mineral substrates that may dust over time, helping preserve the appearance of lime plasters, stone, and similar surfaces.
• Graphenstone Nevada Primer: Good all-round primer paint that is to be diluted to achieve a mist coat and primer for new plaster and lime. Good price and goes a long way!

Not necessarily a primer but a finishing coat when a painted finish is not desired:

Opt for Beeck SP Plus for an effective, transparent, breathable protective coating designed specifically for lime render, natural stone, and porous brick! Our customers love it for preserving the authentic appearance of their surfaces while ensuring a long-lasting finish.

Beeck - SP Plus - A colourless and transparent finish for long-lasting protection of lime, cement, or brick renders. It provides a water-repellent coating while keeping the surface breathable. Fixative primer is only necessary if your coating is applied to fresh lime pointing.

Tips for Using Primers and Helpful Information from our Suppliers

• Pick the appropriate primer by considering the surface (such as drywall, wood, or metal) and the paint type. Don't forget to leverage our offer to consult with us and get expert guidance!
• Always clean surfaces thoroughly before applying primer. For optimal adhesion, lightly dampen the surface first with a water spray bottle.
• Apply an even coat and let it dry completely before painting.
• Every primer is different and serves a specific purpose. Follow the manufacturer’s instructions for optimal results.
• Lime render or plaster should be completely cured before applying paint. While your lime supplier is the best source of advice, typically, you should wait at least 1 month of curing for every 5mm of thickness. In poor drying conditions, this curing period might need to be extended.

Shop our Range of Primers

Keep in mind:

Celtic Sustainables provides information for general use only and does not serve as a formal specification. Since each project is different, it’s advisable to consult a professional before starting your own project. Using this site and trusting its information is entirely at your own risk.

If you need more help choosing the right primer or applying it, feel free to ask! Happy painting!