Before painting my border fortress I gave it two coats of PVA to seal the wood. Once that was done (and the PVA had dried), I undercoated the model using two thin coats of matt Black acrylic craft paint (made by Crelando).

I then dry-brushed the planked area with matt Burnt Sienna acrylic craft paint (made by Crawford & Black).

Once the brown paint had dried, I gave the rest of the model two thin coats of matt Medium Grey acrylic craft paint (made by Reeves).

I tend use cheap acrylic craft paint from a variety of different suppliers, including THE WORKS and LIDL for projects like this. I see no point in using expensive acrylic paints unless there is a particular colour that I want to use that isn’t easily reproduced by mixing my cheaper paints.