What paint to use for rising damp?

[KatM]

I heard there is a specific paint to use for rising damp, when painting the plaster on walls. What specific paint or product is it? 

At what stage do you pop this on? I.e. do you do undercoat, top paint then rising damp paint? Or the other way around - rising damp paint, undercoat, top coat? 

Is it worth painting the whole house with this? Or even just the wet areas, e.g bathroom. The reason I ask is because my home is a 1939 home where there is minimal rising damp visible on the inside and not really any moisture (Ive had to checked), however the outter bricks, some mortar is coming off so I'm worried that down the track it may appear internally. Although I have lived in my place for 17 years now, it's been pretty good, but I will be renting my place out shortly so I also want to prepare and make sure it doesn't pop up when renters are in. TIA

[MitchellMc]

Welcome to the Bunnings Workshop community @KatM. It's tremendous to have you join us, and many thanks for your question about rising damp.

If you're noticing moisture above the first course of bricks on your external brickwork, it's important to know that typical brick construction includes a damp course line. This line is designed to prevent water from migrating up through the bricks. If moisture is present above this level, it might indicate a problem with the damp course, and I recommend having it professionally assessed and addressed.

Loose or deteriorating mortar isn't necessarily a sign of rising damp on its own, though it can contribute to the issue if water is allowed to penetrate the structure.

For interior walls, you can take preventative action by applying a product like Crommelins Aquablock. This can help create a moisture-resistant barrier on plasterboard and masonry, and you can topcoat it with your preferred paint for a finished look. However, it’s important to understand that walls shouldn’t have significant moisture in them in the first place. Using an undercoat like this won't resolve any underlying issues causing dampness but can help prevent further problems once the root cause is addressed.

Please let me know if you have any questions.

Mitchell