For best results you’d need an oil based primer and finish because water based paints will make the strands swell and stand out more than they do already, so it will be difficult to get a smooth finish. But, if the final appearance isn’t important you could use a water based primer for the first coat and then one or two coats of masonry paint to finish.
If you are painting for aesthetic reasons only it doesn’t matter so much but if it’s for preservation and durability you should consider painting both sides of the boards and sealing all edges to prevent the absorption of moisture.
Thanks for your advice. Going to use oil base primer and two coats of masonry paint on both sides and edges. READ MORE...
Best wishes