Black water stains on rendered wall Post your questions and get answers regarding all areas of drives, pathways and patios

[Lizzy74]

Hello, I have outside stairs and the rainwater runs down the rendered wall and stains it.
Is there anything I can do to catch the water before running down?
Can I cover the wall with a waterproof paint to make cleaning easier?
Any suggestions welcome.

[stoneyboy]

Hi lizzy74
Your steps slope downwards to the left as you look at them from the bottom. The staining is caused by the prolonged water run off. You could treat the wall with bleach, allow to dry and paint using a fungicidal masonry paint. You will still need to do regular dosing with a weak bleach solution poured over the steps. Can’t advise which paint will resist the bleach.
Regards S