Primer Calculator for Dubai and the UAE

Primer has one main job. It seals the surface so the paint sits on top instead of soaking in.

A bare wall is like a sponge. Put emulsion straight onto it and the wall pulls the liquid out of the paint. What is left on the surface is a thin, patchy, dusty film. It looks fine when wet and poor when dry.

Primer soaks in on purpose, then sets. Now the surface is sealed, and the paint you put on next stays where you put it.

It does two smaller jobs as well. It gives paint something to grip, which matters on smooth or shiny surfaces. And it evens out colour, so patches of filler do not show through.

Not every wall needs it. These do, without exception.

An old wall that has been painted before, is sound, is clean and is going to be painted a similar colour does not need a primer coat. Wash it, fill any small holes, spot prime just the filled patches, and paint.

That is genuinely the most common repaint in Dubai, so it is worth saying plainly rather than telling everybody to prime everything.

The test is simple. Flick a few drops of water at the wall. If they sit on the surface as beads, the wall is sealed and you can paint. If they soak straight in and darken the wall, it needs primer.

Do the test in a few places. A wall can be sealed in one area and bare in another, especially where repairs have been made.

This is the part worth understanding, because skipping primer is the most common false saving in painting.

Primer usually costs less per litre than a good top coat. It is doing a simpler job, so it does not need the pigments and binders that make finish paint expensive.

Now think about what happens without it. The wall pulls in the first coat, so it does not cover. You put a second on. It still looks uneven, so you put a third. You have now bought three coats of the expensive paint to do what one coat of the cheap one plus two of the expensive one would have done better.

You also spent an extra day. And the finish is still worse, because paint that soaked into a wall does not have the same surface as paint that sat on a sealed one.

So the saving is not a saving. It costs more money and more time and it looks worse.

They are not all the same. Pick by what is underneath, not by price.