How to render or paint stone drainage channel?

Question

I have this stone wall with a drainage channel beside it the house. The walI is old and needs revamping so I want to either paint or render over the stone to hide the old wall and channel. the plan is to put pavers in beside the wall to the right of picture.

Will rendering here work?

Will render stick to the stone? .

JacobZ · Answer

Hi @BettySue,

I've spoken with a number of our suppliers and unfortunately, no one could provide me with a solid solution, mainly because of the stones and the fact it is a drainage channel. Things like render, paint and waterproof membranes would struggle to stick to the stones because they are not porous, so they will not bite and get a great hold on the stones. When you add in the fact that this is a drainage channel, the combination of poor adhesion and constant water, will almost certainly lead to delamination issues.

The only perfect solution I have is to remove the wall altogether and have it replaced with concrete. In doing this, the wall would be tidied up and could be sealed with a concrete sealer or waterproof membrane.

If you wanted to just give render a try and see how it goes, then I would suggest you speak with a professional renderer to see what advice they have and if there is any method they are confident in.

If you wanted to paint, again, there would be no guarantees, but you could certainly try applying an exterior paint and simply see how it goes, but it wouldn't be covered by any kind of manufacturer's warranty.

I'm sorry that I couldn't find a solution. Unfortunately, what might look like a simple scenario is honestly pretty complex.

Let me know if you have any further questions.

Jacob

JacobZ · Answer

Hi @BettySue,

I can't say I am aware of a render that would be suitable directly over stone, especially considering it is a drainage channel. While render might stick initially, the constant exposure to moisture would almost certainly cause it to fail considerably quicker than expected. I would lean more towards painting the wall in this situation.

In saying that, you'll have to let me reach out to our paint suppliers to see what sort of paint they would advise using in this situation as again, being stone and a drainage channel, it isn't exactly a standard application.

Please bear with me, I will reach out to our paint supplier's technical teams to see what they would recommend and get back to you when I have a response. Being a Sunday, it is likely I won't have an answer till tomorrow morning at the earliest.

Jacob