Rejuvenating waterproof membrane on water feature

[Cathy001]

I emptied my water feature for cleaning and would like to redo the waterproof membrane.  I believe the structure is glass reinforced concrete.   Should I paint over it with a primer and Crommelin pond sealer or use a pond liner.  A pictures of the base is attached.  The outside needs repainting as well.  The water feature is over 10 years old.

 

 

[JacobZ]

Hi @Cathy001,

A warm welcome to the Bunnings Workshop community, it is fantastic to have you with us.

You'll have to start by cleaning the surface thoroughly with warm soapy water and a scrubbing brush, ensuring you remove all contaminants that can affect the adhesion of your waterproofing membrane.

Once clean, check for any pinholes in the water feature and fill them with silicone.

After this, allow the water feature to fully dry before applying Crommelin Black Pond Sealer, following the application instructions closely.

This will give you a good solid seal that will keep your water feature watertight for years to come.

Let me know if you have any further questions.

Jacob

[Cathy001]

Hi Jacob

I have pressure washed the inside of the base and it is dry.  Do I still need to scrub with soapy water? Do I remove the blistering parts of the current membrane and prime before recoating? As far as Im aware, the water feature wasn't leaking when it was emptied but  needs topping up once a week when windy or in hot weather .. so no holes in the base.

[JacobZ]

Hi @Cathy001,

You want to remove anything that is not well adhered to the substrate, so if there is any mould mildew, or powdery substances on the existing membrane, then you'll need to remove it by scrubbing. The same applies to the blistering parts of the old membrane as they are no longer well adhered to the substrate.

If the existing membrane is not well adhered in a number of areas, you may need to remove it entirely before starting again, but you would need to assess the surface yourself to determine this.

Let me know what you think.

Jacob

[Cathy001]

Hi JacobZ

I will scrub the inside and reassess the condition.  I'm not sure whether using a pool liner would be better than total removal of the membrane.  I was looking for the easiest option..

Many thanks for your advice.

[JacobZ]

Hi @Cathy001,

The main reason I would use a paint-on membrane as opposed to a pool liner is because of the stem in the middle.

The pool liner would need to be cut and stretched up the stem to the height of the water to ensure everything is watertight. I imagine it is possible, but it would be more difficult than a painted on membrane.

Let me know what you think.

Jacob

[Cathy001]

Hi Jacob

I hadn't thought about the middle stem.  Thanks for the advice.  I will go with the painted on membrane and see how I go.

I have the Crommelin Diamondcoat base tint to redo the outside part of the feature as well.

[JacobZ]

Hi @Cathy001,

Sounds like a plan.

Let us know how you go and don't hesitate to reach out if you need any advice along the way.

Jacob