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Priming – YouTube Series Episode 2

To run alongside our new YouTube series, we have a dedicated series of blogs detailing the processes described in the series. We will cover every single step of the installation process, from an unprepared substrate, all the way to the aftercare stage. This includes customer and system aftercare. The series is broken up into the following steps:

  1. Starter Track
  2. Priming
  3. Insulation, adhesive, and fixings
  4. Beading and verge trims
  5. Basecoat and mesh
  6. Topcoat (priming and rendering)
  7. Tips and aftercare
  8. Our other services

Episode 2 covers the priming portion of the installation process. This refers to the priming of the substrate which can mean several things therefore some clarification is required. The process is essentially preparing the substrate, however, it also includes moisture and dust control. Some substrates can be pretty dusty and crumbly and therefore require priming. If left alone, the subsequent adhesive, basecoat or topcoat will tend to peel off and also not adhere properly.

Another reason for using a primer is to establish a mechanical key for adhesion. Substrates can often be slick and hard to stick onto, therefore priming them to establish a key is crucial to the stability of the installation.

Types of priming products

At EWI Pro, we have developed several options for preparing the substrate. All substrates are different and have different characteristics and issues, therefore, we have a wide range of primers to suit your needs.

Fungicidal Wash – Perfect for helping to prepare a substrate before applying our EWI or render systems. The product takes just 24 hours to kill all microorganisms on the substrate, including algae, mould and lichen. The wash is applied using either a brush, sponge or cloth. It also prevents regrowth for up to 6 months.

Universal Primer – Boosts the adhesion of materials to the substrate. An integral product for smooth substrates where an artificial key is required for binding the materials, the primer contains quartz aggregate to create a textured surface onto which the adhesive layer can bind easily. It is also tinted red which enables easy application and ensures a robust finish.

Water-Based Primer – The primer dries completely colourless and works by limiting the amount of water that the substrate absorbs from the adhesive, thereby ensuring the effective application of materials. It provides enhanced adhesion and enables a dependable and durable finish.

Deep Penetrating Primer – The primer dries completely colourless and also works to stabilise the substrate, limiting the absorptivity of the substrate and thereby ensuring the effective application of materials. The primer is also ideal for newbuild brick and blockwork, providing enhanced adhesion and enabling a dependable and durable finish.

How to apply primer

Much like all projects, substrate preparation is key. The wall must be clean, dry and dust-free. Be sure to clear any paint or substance otherwise, it may affect how the Adhesive performs. One of the best ways to achieve a clean and ready surface is to use a high-pressure water jet. If this is not possible, prepare the wall manually using a wire brush.

If you’re working on an existing render or pebbledash, you must check that this is structurally sound before starting the work. Lastly, if you find the render or pebbledash to be weak, we strongly recommend removing this prior to the installation.

Once the substrate has been prepared, it then needs to be primed before any insulation can be applied. One initial procedure we encourage is the application of EWI-360 fungicidal wash. This product removes all biological growth and prevents re-growth for up to 6 months. We recommend priming the substrate with EWI-301, which is a deep-penetrating water-based primer. It works in a similar manner to PVA primer, by helping to seal porous surfaces and is most effective on highly-absorptive substrates

The amount of primer required will depend upon how absorptive the underlying substrate is. Typically, this can be anywhere from 50- 300ml per m2. For those of you working on low-suction substrates, it’s likely you will need EWI-310 Universal Primer. This contains silicate, which enhances the adhesion of the insulation boards. Both EWI-301 and EWI-310 can be applied by brush or roller. The primers will take approximately 4 hours to dry. However, additional coats may be required. 24 hours should be left between primer coats.

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