Primer Paint

Paint primers are specially formulated to stick easily to the surface material, laying a resilient foundation base that ensures better adhesion for the paint on top. The primer base layer penetrates the bare surface, smoothing out porosity and forming a professional-looking paint finish. There are a range of different interior and exterior primer formulations out there, each suited to a different kind of application.  

Whilst every professional decorator you’ll ever talk to will strongly recommend investing in a good-quality paint primer, it can be tempting to just simply jump over the priming step and save yourself some money, time and effort. But what impact does skipping the primer have? Is it really essential or can you go without?  

Whilst primer may seem like an unnecessary extra, it actually makes a very significant difference in how your final paint finish turns out. Many surfaces such as drywall soak up paint fast, which is definitely not what you want to happen, especially if you’ve invested in a pricy paint. By priming the surface first, the application will not only be far smoother and easier but you’ll need fewer coats in total to achieve the full-intensity colour you want.  

Primer can even help in covering up those pesky stains and crayon marks you just can’t seem to hide. Specialist stain-blocking primers can block out all manner of unsightly imperfections, meaning you can focus on creating a perfect, even colour finish without going over the same stain again and again.  

Whilst primers are beneficial in a large variety of applications, there are some cases where missing the primer won’t make much difference. For example, surfaces that are already painted and in good condition can often just be cleaned, sanded and over-coated with no additional priming required. 

To paint a clearer picture of what needs priming and what doesn’t, it’s easier to discuss the specific applications where priming will almost always be required before you paint:  

Porous Surfaces – As a general rule, you should always prime the surface beforehand if it is porous. When a surface is porous it can absorb water, oil, moisture, odour and stains so a layer of primer must be applied to prevent the paint from absorbing straight into the material.  

Glossy Surfaces – Paint typically doesn’t adhere to glossy surfaces very well without a primed layer first.  

Stained Surfaces – If your walls are stained, whether that be water damage, smoke stains or even ink marks, a primer will act as a blocker to seal in the stains so that they don’t leak back through the paint.  

Surfaces with an Odour – Believe it or not, internal walls soak up very strong odours and retain them within the home. To tackle the smells for good and stop them from coming back, a good-quality primer can be used to seal in and eliminate odour effectively. Pretty clever, right? 

Dramatic Colour Changes – If you’ve undergone a drastic aesthetic change and want to switch from a very dark shade to a much lighter colour, using a primer can save you the time and hassle of applying six or seven coats whilst ensuring an even, saturated coverage.   

So, now we’ve highlighted when and where primers should be used, let’s investigate the type of primer you should reach for in each kind of application.   

Interior Applications 

Internal Walls 

You generally have two common options when it comes to priming internal walls: oil and latex primers. Water-based latex primers are the more popular option with easier clean-up, enhanced durability and more flexible installation. However, oil-based options are suitable too, providing good paint coverage and resistance to peeling, cracking and blistering.  

Drywall  

Latex primers are the best option for drywall surfaces, creating a smooth and even surface for the paint to securely adhere to.  

Moisture-heavy Areas (Kitchen/Bathroom) 

Perfect for moisture-prone spaces such as the kitchen and bathroom, vapour barrier primers help to reduce the passage of moisture through your walls to your property’s exterior. This not only minimises the risk of moisture pushing the paint from your external walls but also helps to maintain a more comfortable room environment in the colder winter months.  

Semigloss/Gloss Paint 

When applying gloss or semi-gloss paints, a latex enamel primer will ensure the topcoat of paint dries to its maximum gloss level for the best-looking finish.  

Shiny Surfaces (Glass, Ceramic Tile,) 

Shiny surfaces such as glass or ceramic tiles can be tricky for the paint to adhere to. A practical way of ensuring full adhesion to the surface is by first applying a specialist bonding primer.   

Stained Surfaces 

Stain-blocking primers are specially formulated to prevent stains from bleeding back through a newly painted surface. You’ll find it find it most beneficial to buy a stain-blocking primer based on which formulation is the most effective to tackle your particular stain. For example, oil-based primers are best for covering water stains, whilst shellac-based products are tinted to prevent the bleed-through of mildew.  

Exterior Applications 

External Walls 

Whilst oil or latex primers are suitable for use externally, it's important to bear in mind that the primer you use should match the specific type of paint you are using to finish.  

New Wood (Unpainted) 

If the wood is new and the species won’t leech tannins into the paint surface, an acrylic latex or oil-based exterior primer is best to use. For woods that will or have already stained, a shellac or oil-based stain-blocking primer is your best bet.  

Painted Wood 

If after scraping the loose paint and sanding down, all of the chalk cannot be removed, an oil-based primer is for previously painted wood. If the old paint layer is in good condition and well-adhered, an oil primer can be used but it is not always a vital step.  

Weathered Wood (Unpainted) 

After correctly sanding and prepping the surface, a latex or oil-based primer is ideal for use on weathered, unpainted wood.  

Composite Wood 

As composite wood is comprised of plastic and wood, you need to ensure the primer you apply is suitable for use on both material types. An acrylic latex primer is often a good choice for composite wood applications.  

Masonry 

A latex masonry primer will create a smooth paintable base on new masonry and old porous surfaces.  

Aluminium or Galvanised Iron 

After correctly removing any white oxide, any corrosion-inhibitive metal primer can be applied to the bare metal surface. 

Ferrous Metals 

Latex or oil-based rust-inhibitive primers can be applied prior to painting ferrous metal surfaces after rust has been wire-brush removed and rinsed.