Lime, silicate and clay paints

1. Introduction

If you are thinking of renovating your home or giving a space a makeover, it is normal to have questions when you hear about ecological paints, lime, silicate or clay.
This guide is designed to help you:

• Understand simply what options you have.
• See what you can do with your current wall (plaster, plasterboard, popcorn texture, plastic paint, etc.).
• Choose the ecological coating that best fits your project:
  – Lime paints
  – Silicate paints
  – Clay paints

You don’t need technical knowledge: we’ll go step by step, with clear language and common on-site examples. For more technical questions, tools, application techniques, etc., you can always consult the product data sheets or ask us for help.

2. Defining the current substrate

Before choosing the ecological paint, the first step is to know our starting point: What type of wall do I have now and what am I willing to do with it?

2.1 Mineral substrate

These are walls made with materials such as:

• Cement
• Lime
• Plaster
• Perlite
• Concrete: These are usually the “structural” walls or traditional renders.
  Key question: are they in good condition (firm, no damp, no major flaking)?
• If the wall is sound, clean and firm → usually good preparation will suffice and you can apply a lime, silicate or clay paint.
• If there is damp, saltpetre, very loose areas or mould → the problem must be treated first (not just “covered up” with paint).

2.2 Plasterboard (laminated gypsum boards)

Plasterboard is a very common substrate in interior renovations:

• Lightweight walls and ceilings.
• New partitions built during a renovation.

Here it is important to know whether it is:

• New, unpainted plasterboard.
• Plasterboard already painted with plastic paint.

In both cases you can work with ecological products, but the preparation will be
different.

2.3 Existing paint

Many walls already have several layers of plastic paint (standard, satin, even with very intense tones).

Important questions:

• Is the paint well adhered or does it peel off easily? (this can be checked with a
  simple adhesive-tape test).
• Is the surface matte or very satin/glossy?
• Are there repaired areas, patches or stains?

Based on this we will decide whether:

• We only need to open the pores and clean
• It is advisable to remove parts or even out with a skim coat (filler, lime, clay…).

2.4 Popcorn texture (gotelé)

Many homes still have popcorn texture; it may be:

• On plastic paint.
• On old distemper.

Key step: decide whether you want to keep the texture and just apply an ecological paint, or remove it and achieve a smooth wall for a more decorative finish. From that decision come options of sanding, scraping or skim-coating with lime, plaster, filler or clay.

2.5 Deciding on the degree of intervention

Once the substrate is identified, it is best to be clear about how far we want to go:

Minimal intervention

• Light sanding of the current paint.
• Cleaning and touch-ups.
• Direct application of the new compatible coating. Helping you choose the option that best balances aesthetic result, budget and build time.

Medium intervention

• More intense sanding or toning down of the popcorn texture.
• Skim-coating the wall with filler, plaster, lime or clay to improve the substrate.

High intervention

• Removal of paint layers.
• Removal of the popcorn texture (if applicable).
• In some cases, removal and renewal of the substrate (very deteriorated, serious damp,
  etc.).

The guide will help you choose the option that best balances aesthetic result, budget and build time.

3. Substrate preparation

Once the level of intervention has been decided, we move on to preparing the substrate. This is where the success of the job is really decided: a good ecological paint needs a suitable base.

This section offers several alternatives so the client can choose the one that best fits their case. We will always recommend the most suitable RedVerde products for each situation.

3.1 Sanding the current substrate

When it is used:

• Plastic paints in good condition but very satin or with several coats.
• Popcorn texture that you want to “reduce” but not remove entirely.

Objective:

• Open the pores and improve adhesion.
• Slightly even out the texture.

Basic steps:

1. Protect the area well (there is quite a lot of dust).
2. Sand with the appropriate grit (by hand or machine, depending on the surface).
3. Vacuum or carefully clean off the dust.

3.2 Removing the current substrate and applying a new one

When it is considered:

• Popcorn texture that you want to remove completely.
• Very deteriorated renders, with many layers of paint, saltpetre or old damp.

Possible solutions:

• Remove the old coating down to a sound substrate.
• Apply a new substrate: lime mortar, plaster, lime or clay renders, etc.

This option involves more intensive work, but leaves the wall fully prepared to receive ecological paints with the best possible behaviour.

3.3 Skim-coating the current substrate

It is a very common and versatile solution: “I use what I have, but I even it out with a new coat”.

Common skim-coat materials:

• Lime skim coats
• Natural filler
• Plaster
• Clay mortars or renders

When it is worthwhile:

• To smooth or cover popcorn texture.
• To even out walls with small defects, patches and repairs.
• To move towards a substrate more compatible with lime, silicate or clay.

3.4 Summary of options according to the state of the substrate

• Substrate in good condition, smooth or almost smooth → Light sanding + cleaning + primer (if
  needed) + ecological coating.
• Substrate with moderate texture (light popcorn) or many repairs → Sanding + partial or total
  skim coat + preparation + ecological coating.
• Very deteriorated substrate or with “hard” popcorn texture to be removed → Removal of the
  old substrate (or part of it) + new substrate (lime, plaster, clay…) + ecological
  coating.

4. Choosing the decorative paint

Now that we are clear about the substrate and how we are going to prepare it, comes the most rewarding part: choosing the ecological finish we want to see every day in our home.
The main final systems we recommend at RedVerde are:

• Lime paint
• Silicate paint
• Clay paint

4.1 Lime paint

Ideal for mineral walls (plaster, lime mortars, renders). Very breathable and with
a mineral matte look. It helps regulate ambient humidity and prevent mould.

Recommended RedVerde product: COLORLIME interior/exterior lime paint

Basic application guidelines:

1. Firm, clean and dry mineral substrate.
2. Two coats of lime paint, respecting drying times and avoiding extreme temperatures, strong wind or high humidity.

4.2 Silicate paint

Especially interesting on facades and mineral substrates in good condition. It fuses with the
substrate, creating a very durable and breathable finish.

Recommended RedVerde product: COLORMIN interior/exterior silicate paint

Basic application guidelines:

1. Mineral substrate without paint.
2. Two coats of silicate paint. Avoid rain or fog while it hardens (curing).

4.3 Clay paint

A very decorative option for interiors, with a deep, warm matte finish. It helps
regulate indoor humidity and improves the sense of comfort.

Recommended RedVerde products: CLAYFIX clay paint.

Basic application guidelines:

1. Preferably mineral substrate or a compatible skim coat (plaster, lime, clay).
2. Cleaning and application of primer.
3. Application of 2 coats of clay paint, as indicated on the technical data sheet.

4.4 Hybrid plant + lime paint

A balanced option for interiors, combining plant-based components with lime. It offers a natural matte finish, good breathability and behaviour very well suited to inhabited spaces, helping to regulate ambient humidity and improve indoor comfort.

Recommended RedVerde product: COLORNATUR ecological interior paint.

Basic application guidelines:

• Firm, clean and dry substrate, preferably mineral or correctly prepared.
• Light sanding and cleaning if there is existing paint.
• Application of a compatible primer, if necessary.
• Application of 2 coats of hybrid plant + lime paint, as indicated on the technical data sheet.

Simple criteria for choosing

As a quick guide:

• If you are looking for maximum breathability and a very mineral look, and you have a mineral substrate →
  LIME or SILICATE paint, depending on the case.
• If you are looking for a very warm finish, soft to the touch and very decorative indoors → CLAY
  PAINT
• If the priority is exterior durability on facade renders → usually
  SILICATE PAINT (depending on substrate and conditions).

5. Summary table – Paint types and recommended use

6. RedVerde links and contact

General reference pages:

• Ecological paints
• Ecological interior paints
• Ecological exterior paints

Guide summary

If you have questions about your wall or don’t know which system to choose, you can contact the RedVerde team
via the website form or call us directly from the
Contact section.