How to waterproof and seal a sandstone waterfall feature in pool?

[Lettuce]

I'm needing advice please.  My sandstone water feature waterfall in my pool area is 13 years old and never been resealed.  The sandstone is disintegrating and flaking off, which results in my pool having a great deal of coarse and fine sand in it, as well as larger pieces of the sandstone.

There is fine dust covering the feature.  Which is the best way of cleaning the sandstone feature without damaging it more?  I'm presuming I need to remove all the dust and debris before sealing it?

Which waterproofer and/or sealer should I use?  Would it be easier if it was sprayed on, or brushed on?  Any advice would be most appreciated.

Thank you.

[MitchellMc]

Welcome to the Bunnings Workshop community @Lettuce. It's marvellous to have you join us, and many thanks for your question about sealing a water feature.

It sounds like you're facing a challenging situation. Flaking off isn't something I'd typically associate with sandstone, as it seldom flakes. However, the presence of sand particles indicates that it is potentially sandstone or perhaps a manufactured stone.

The first step to address this would be to clean the surface thoroughly. The surface is compromised, so you'll need to pressure wash it and scrub it with a broom to remove loose particles and debris. Even after cleaning, the surface will still be considered compromised, so most sealer manufacturers won't recommend their products for such conditions. If the stone continues breaking down and releasing particles, the sealer will come off with them. The disintegration of the sandstone could be due to exposure to chlorinated or salt water flowing over it. This means any sealer you use must be suitable for a constantly wet environment and withstand salt or chlorine exposure.

I'm not aware of any specific sealer that perfectly suits this application. You could try the Crommelin 1L Natural Finish Penetrating Sealer And Water Repellent, though due to the compromised surface, wet environment and the presence of salt or chlorine, how long it will last is hard to determine.

Both spraying and brushing have pros and cons. Spraying can ensure a more even coat, especially on irregular surfaces, but it can be messier and require more preparation to protect surrounding areas. Brushing allows for more controlled application, particularly in tighter spots, but it can be more time-consuming.

Please let me know if you have any questions.

Mitchell
 

[Lettuce]

Thank you Mitchell!  Your advice was most appreciated!

I used a stiff broom and loosened most of the sand and loose pieces of sandstone and sprayed Batseal high porosity Sealer onto the wall.  One can did two coats.

I don't feel that it is enough, however, so will get a waterproofing and paint that on as well.

Do you know anything about pool water features?  I need to try to stop/block mine from working, and then there won't be further issues.

Thanks again.

Lyn

[MitchellMc]

Hi @Lettuce,

I'd suspect that near your pool pump, a valve tap can be turned to allow water to be pumped or block water from the water feature. If it's not labelled, it might not be particularly obvious. You'll need to run the pump and then turn a few valves to see which isolates the feature. If no valve controls the feature, it might be worth looking behind the feature itself. If you can find the pipe bringing water to it, you should be able to remove it and the cap off the end. Ensure you can find a suitable fitting to block the pipe before removing it.

I note the water is not running in your images. Does it only come on when you're running the pool pump?

Mitchell