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Do You Need An Undercoat for Gloss Paint?

If you’re about to decorate your home with gloss paint it’s a good idea to know if you need to use an undercoat or not first. Find out all the answers in this article. 

Homeowners spent on average £400 pounds more on home renovations than usual during lockdown. Now, more than ever we want to make our safe place as beautiful as possible. Business owners are also putting paint to the wall in an effort to boost trade and make up for trading time lost during the pandemic.

One of the more low cost and quick ways to transform any home is to paint it. With a coat of paint the entire look of any space is transformed and rejuvenated. Of course, it has to be painted well to fully complete the look. Paint that has not been applied properly, or with adequate preparation or drying does not enhance a space, and may even detract from its overall look and feel.

One of the biggest DIY mistakes is when you apply gloss incorrectly, because it can peel, crack or otherwise tarnish. Can adding an undercoat prevent this from happening? Is an undercoat essential when painting with gloss? To help you paint with gloss effectively, here are all the answers below:

Do You Need An Undercoat for Gloss Paint?

You need an undercoat for gloss paint if there is a strong colour change, if the surface is bare (in addition to a primer), or the paint underneath is in bad condition. Otherwise, with some abrading of the surface, you don’t always have to apply an undercoat for gloss paint.

Note that it is almost always essential to sand the surface before applying gloss, however.

Can You Paint Over Gloss Without An Undercoat?

You cannot paint over gloss without some degree of preparation first. It will just peel in the future if you don’t prepare the surface you are painting on.

To prepare you usually have to add a primer, sand, undercoat, or some or all of these things depending on the surface underneath.

Sanding over the surface gives the gloss something to key to and this is usually a good step to take before adding an undercoat or a gloss paint that is self undercoating.

Others might choose to apply sugar soap, let that dry, add a primer and then paint gloss.

In addition to these measures, an undercoat is almost always a good idea. This is certainly the case when there is a strong colour change taking place, or when the paint underneath is in very bad condition (when you should also sand before applying an undercoat). If the paint underneath is in good condition and you have roughed it so that the gloss going on can adhere to it, then you could get away with not applying an undercoat.

Do You Need to Prime Before Glossing?

Priming before glossing is not a yes or no for every surface as it really does depend on the surface you are painting on. Metal that has not been primed, for example, has to be primed before gloss is added as the gloss simply won’t stick and will flake away almost immediately. Wooden surfaces may need knotting, priming, undercoating and then painting.

With walls, if the surface is porous as with concrete or plaster you need to prime the surface first before painting otherwise it will suck the paint up and look patchy. Previously painted walls simply need to be prepared as above (sanding and undercoats) before being painted with gloss. Of course, using gloss on walls is a bold move!

What Colour Undercoat for Blue Gloss?

Colour matching your primer and undercoat to your paint ensures that the final result is beautiful and colour correct. If you cannot match your undercoat to the final paint colour you should try to use:

  • Dark grey or black undercoat for dark blue gloss
  • Mid grey undercoat for mid, neutral blues
  • Light blue or light grey undercoat for pale blues

If you are unsure it is important to ask for advice from the warehouse you are buying the paint from so that you use the correct products for true depth of colour when you finish.

Preparation Pays Off When You Paint With Gloss

As a general rule, it always pays off to prepare as much as possible before applying gloss. Undercoats are usually needed, with sanding and priming adding to a complete process that contributes to a better overall result. With the right paint system, you can enjoy stunning, shiny, glossy painted woodwork that boosts your home aesthetic.