How Many Coats of Basecoat Do I Need?

When rendering and painting walls, the devil is in the details. One frequently asked question in this domain is: “How many coats of basecoat do I need?” The simple answer is that it can vary depending on the material you’re using and the surface you’re working on. In this blog post, we’ll dive deeper into the world of basecoats, adhesives, and different types of renders—focusing particularly on the high-quality products supplied by the EWI Store.

What is a basecoat?

The term “basecoat” may seem straightforward at first glance, but in rendering and painting, it serves multiple critical functions that warrant closer inspection. A basecoat is a preparatory layer applied to a surface to ensure that subsequent coats, such as the finish or topcoat, adhere properly and perform optimally. However, its utility doesn’t stop at being a mere “undercoat.” Here’s a more detailed look at what a basecoat is and why it’s so important.

Physical properties

A basecoat is typically formulated to have high adhesive properties, allowing it to bond effectively with the substrate or the surface to which it is applied. Depending on its composition, a basecoat may also offer additional benefits, such as water resistance, flexibility, or increased breathability for the wall.

Compatibility

Not all basecoats are suitable for all types of surfaces or topcoats. For instance, a basecoat designed for mineral render might not be the best fit for a silicone-based topcoat. Understanding the compatibility between your basecoat and other materials is crucial for long-lasting results.

Surface Preparation

One of the primary functions of a basecoat is to even out the irregularities in the surface to which it is applied. Whether you’re working with a newly built wall or a surface that has seen better days, a basecoat can fill in minor cracks, smooth out bumps, and provide a level base for the final finish.

Adhesion and durability

Beyond surface levelling, a high-quality basecoat enhances the adhesion between the wall and the subsequent layers. This ensures that your topcoat or render doesn’t peel, flake, or suffer from other forms of premature wear and tear.

Insulation and protection

Some specialised basecoats also serve additional functions, such as providing thermal insulation or added protection against moisture ingress. EWI Store, for instance, offers basecoats formulated to work with their insulating systems, ensuring both energy efficiency and durability.

Aesthetic considerations

The colour and opacity of your basecoat can impact the final appearance of your topcoat. Light-coloured basecoats are typically preferred when using lighter topcoat shades, as they don’t alter the hue or require multiple topcoat applications to achieve the desired finish.

EWI Store basecoats and how many coats are required

The EWI Store range of basecoats is incredibly diverse; and a good thing too! Our customers’ projects vary in complexity, therefore, our range of basecoats has to be suitable. Some projects may require a lightweight wall system, whilst some require enhanced durability and the capability to attach external wall insulation boards.

EWI-225 Premium Basecoat

Our most popular and versatile basecoat. It has two major benefits that separate it from our other basecoat. Firstly, it is a dual-purpose product, which ultimately reduces wastage on-site as only one product is required. Crucially, it can also support any form of insulation board including mineral wool which is notoriously heavy. Despite this, it does not sacrifice any of its durability, flexibility, or breathability.

Coats required – One when embedding mesh directly into it. However, you can also use two thinner coats and embed the mesh with the second layer.

Adhesive coats required – A full coverage of the insulation board or the dot and dab method.

EWI-220 EPS Basecoat

As the name suggests, EWI-220 EPS Basecoat is the ideal product to act as an adhesive for EPS insulation boards. However, it is not suitable to attach heavier boards like mineral wool and phenolic foam. Despite this, it does not sacrifice any of its strength or flexibility and continues to be a dual-purpose product.

Coats required – One when embedding mesh directly into it. However, you can also use two thinner coats and embed the mesh with the second layer.

Adhesive coats required – A full coverage of the insulation board or the dot and dab method.

EWI-222p Performance Basecoat

Bridging the gap at a great price point is the EWI-222p Performance Basecoat. It performs to the same level as Premium Basecoat and is a great basecoat for render-only projects. It also meshes well with our Silicone Render range to ensure a robust and long-lasting decorative finish.

Coats required – One when embedding mesh directly into it. However, you can also use two thinner coats and embed the mesh with the second layer.

Adhesive coats required – A full coverage of the insulation board or the dot and dab method.

EWI-269 Lightweight Basecoat

EWI-269 Lightweight Basecoat is designed for both internal and external use. You can apply it to high-performance blockwork, lightweight masonry structures, and stonework. If you use a machine, you can also apply the Lightweight Basecoat up to 25mm in one pass. As it is a lighter-weight basecoat, it cannot be used for insulation purposes.

Coats required – One coat, up to a thickness of 25mm when spray machine applied.

One Coat Dash Cover

Updating or revitalising a pebbledash exterior is commonly seen as a daunting endeavour. Applying paint to it often results in a less-than-attractive finish that deteriorates quickly. Furthermore, completely removing the pebbledash is not only a laborious and costly process but also poses a risk to the structural integrity of the building underneath.

In contrast, EWI Store’s One Coat Dash Cover (OCDC) provides a straightforward and efficient way to refresh a pebbledash surface. This specialised solution has numerous benefits that position it as the preferred choice for homeowners seeking to modernise their external walls.

Engineered to be effective with just a single layer, OCDC considerably cuts down on both time and labour expenditures linked with upgrading pebbledash. Unlike conventional approaches, this one-and-done application eliminates the need for multiple steps, thus offering a time-saving and economical alternative.

How many coats of renders and paints do you need?

You often only need a single coat of silicone render to achieve the desired finish. Silicone render offers robust coverage by design, fills in imperfections, and provides a durable, weather-resistant surface. While some specific aesthetic or structural needs may require a second coat, this is usually not the norm.

For silicone paint, you commonly apply one coat and let it dry fully before assessing the finish. To enhance the colour depth or ensure uniform coverage, especially on surfaces with varying absorption rates or pre-existing colours, a second coat is frequently necessary. However, because silicone paint generally provides superior coverage and durability, you rarely need a third coat, unless you’re targeting a very specific finish or colour intensity.

Let us know how you use basecoat and render!