Primer for old plaster vs primer for new plaster: how they differ and which to choose

What primer is, and why you can't skip it

Primer is to a wall what a foundation base is to make-up. Nobody sees it, but without it, everything you put on top goes patchy, comes off easily and isn't an even colour.

Primer's main job is to get the wall's surface ready to take the topcoat, help the paint grip better, and make the paint on top come out even across the whole wall, without blotchy patches. However beautiful the colour, if the base isn't ready, it won't stay beautiful for long.

How old concrete primer and new concrete primer differ

An old concrete wall is one that has been painted before, or has been through years of sun and rain. Its problems are dust, greasy marks, flaking old paint, and sometimes algae or mould. A wall like this takes Voqe Primer old concrete.

A new concrete wall is one that has just been plastered and never painted. New plaster needs time to cure first. Wait at least 1 month, clean off dust and oil marks, then use Voqe Primer new concrete, a water-based primer, in 1 coat.

If you're not sure which kind your wall is, ask a simple question: has this wall had paint on it before? If it has, or it's a house that's been lived in for a long time, use old-concrete primer. If it's freshly plastered and you can still see bare plaster, use new-concrete primer. Still can't tell? Send a photo of the wall on LINE @dynohomes and the team will take a look for free.

• Painted before, or a house that's been lived in for a long time: old-concrete primer
• Newly plastered, never painted: wait 1 month for it to cure, then use new-concrete primer
• Not sure: send a photo of the wall on LINE @dynohomes

Preparing the wall before priming

An old concrete wall must be clean, with no dust, no greasy marks and no flaking old paint. Scrape off every loose part. If there's algae or mould, wash it with a mould remover, rinse with water, then let it dry completely before priming.

For a new concrete wall, once it has fully cured, brush off the dust and wipe off oil marks. Tape the edges of door and window frames, switches and the ceiling, just as you would to paint for real, because primer can make a mess too.

Voqe primer prices, and which size is best value

Voqe Primer old concrete comes in 4 sizes: 0.946L ฿205, 3.785L ฿630, 9L ฿1,030 and 18L ฿2,060. Per litre, the small size works out at about ฿217 a litre (205 ÷ 0.946), the 3.785L at about ฿166 a litre (630 ÷ 3.785), and the 9L and 18L at about ฿114 a litre (1,030 ÷ 9 and 2,060 ÷ 18).

Voqe Primer new concrete comes in 3 sizes: 3.785L ฿630 (about ฿166 a litre), 9L ฿1,245 (about ฿138 a litre) and 18L ฿2,390 (about ฿133 a litre). The more rooms you're painting, the better value the big tubs are.

To work out how many litres a room needs, measure the total wall area and compare it with the coverage rate on the product page. Primer goes on in just 1 coat, so you use less of it than the paint itself, which goes on in 2 coats.

• A small room or a single wall repair: old-concrete primer 0.946L ฿205
• One bedroom: the 3.785L size, ฿630
• A whole house or several rooms: the 9L or 18L size

Primer under Wall Paint and under Mineral Finish

Under Voqe Wall Paint, the system is 1 coat of primer, then 2 coats of paint. Wall Paint is touch dry in 20–30 minutes and ready for a second coat after 1–2 hours, so one bedroom can be finished in a day.

Under Voqe Mineral Finish, the system is the same: 1 coat of primer, followed by 2 coats of Mineral Finish. New walls take new-concrete primer; old walls take old-concrete primer. A good primer lets the brush pattern of the mineral finish come out beautifully even, without blotches where the wall absorbs paint unevenly.

If you'd rather not prepare the walls yourself, Voqe offers a Supply & Apply service with trained applicators, who take care of everything from scraping off old paint and priming to the final paint.