How to damp proof concrete path?

haitchb

Hi all,

We planted a row of plants a couple of months ago in a garden bed that runs between the fence and our perimeter footpath. 2-3 weeks after planting I started to notice some efflorescence and moisture on the footpath that seems to correspond with the radius of the irrigation. See pictures below which are from the few weeks ago.

After removing the mulch + soil from the footpath edge to allow it to dry and changing watering technique, the issue has mostly resolved and the concrete path has almost returned to normal. However, how can I reduce the chance of this happening again? The other side of the house will be getting lawn later this year and may be next to our footpath, so I want to do all I can to protect areas from moisture!

I found this product online and in-store: https://www.bunnings.com.au/gripset-betta-1l-waterproofing-membrane-bitumen-rubber_p0960165. Would this help with this situation? Would I need to prep / prime the area first?

Appreciate any help that can be provided.

Cheers,

Harry

MitchellMc

Hi @haitchb,

What you’re seeing is likely due to water consistently sitting up against the edge of the slab, especially from irrigation. Concrete is porous, so it can wick moisture, and that often shows up as efflorescence or damp patches, particularly after watering. Applying a waterproofing membrane like the Gripset Betta product you linked to can definitely help. It would be best applied along the vertical edge of the concrete where it meets the garden bed. This creates a bit of a barrier and should reduce how much moisture is able to soak through from that side.

Keep in mind, though, that moisture can also get under the slab and rise up through it, especially if the ground stays wet for long periods. That’s harder to treat unless you’re lifting the path, which isn’t practical in most cases, but thankfully, that kind of upward moisture movement is usually slower and less of a concern than direct surface or side exposure.

If you go ahead with the membrane, I’d recommend cleaning the edge well before applying — just make sure it’s free of dirt, loose material, and any white salts from previous efflorescence. 

Please let me know if you have any questions.

Mitchell