Hi guys, I’m trying to repair our large outdoor concrete fountain. Over time it has developed algae staining and some surface pitting. The main issue is that there are deeper holes and voids on the underside of the fountain plates, so I need a repair product that can: * adhere well to old concrete * be suitable for overhead (ceiling-like) application * fill deeper voids without sagging or falling out * withstand constant water exposure once the fountain is running again Ideally I would also like a finish that is reasonably light in colour so it can be painted or sealed afterward. Once the cement repair is cured, I'd like to: * colour it (ideally light/white or neutral base) * then seal it for permanent water exposure I’d really appreciate specific product recommendations and any things I need to take note of. Thanks in advance!

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How to repair pitted concrete fountain for painting?

Hi guys, I’m trying to repair our large outdoor concrete fountain. Over time it has developed algae staining and some surface pitting.

The main issue is that there are deeper holes and voids on the underside of the fountain plates, so I need a repair product that can:

adhere well to old concrete
be suitable for overhead (ceiling-like) application
fill deeper voids without sagging or falling out
withstand constant water exposure once the fountain is running again

Ideally I would also like a finish that is reasonably light in colour so it can be painted or sealed afterward.

Once the cement repair is cured, I'd like to:

colour it (ideally light/white or neutral base)
then seal it for permanent water exposure

I’d really appreciate specific product recommendations and any things I need to take note of. Thanks in advance!

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JacobZ

Hi @parigi,

Welcome to the Bunnings Workshop community, it is wonderful to have you with us.

I believe a repair mortar of some sort would be the best option, but I am not 100% certain what the best product would be. I have made some enquiries with our suppliers and am just awaiting a response from their technical support. When I have an answer I'll be able to provide further guidance on the best product for filling the holes.

In terms of colouring, assuming a cement based product is the answer, then it should be able to be coloured using a white oxide such as this https://www.bunnings.com.au/dulux-avista-oxide-1kg-white-cement-colouring_p0760496 .

Once the holes are filled, then the fountain can be sealed using https://www.bunnings.com.au/crommelin-1l-clear-pond-sealer_p0960202 to prevent issues stemming from constant submersion in water.

Please bear with me, I will get back to you with further information when our suppliers have responded. As they generally do not operate over the weekend, it could be a few days until I have a response.

Jacob

parigi

Thanks for the reply @JacobZ! Looking forward to your reply! 🙏

JacobZ

Hi @parigi,

I've spoken with our supplier Sika, and they recommended this https://aus.sika.com/en/construction/concrete-repair-protection/concrete-repair-mortars/cementitious-repairmortars/sika-monotop-723n.html which is designed for use as a concrete pore sealer and levelling mortar.

Unfortunately, as this is a fairly specialised product, it is not stocked in our stores, but if you speak with your local store's Special Orders team, they should be able to get in touch with Sika and get you a price, place an order and arrange delivery to your local store.

Let me know if you have any further questions.

Jacob

parigi

Hey @JacobZ, appreciate you checking with Sika.

One follow-up question before I go ahead with the order:

After using MonoTop 723N to repair, the cured areas will be grey while my fountain is an off-white concrete. If I want the entire fountain to have a consistent colour before sealing, what is the correct next step?

Most sealers I have seen are clear, so I assume they will not correct the colour difference between the original surface and the repaired areas.

Thanks for the help!

JacobZ

Hi @parigi,

That's what the oxide is for. By mixing some white oxide in with your mortar, it will help to colour it closer to that of your fountain.

You might have to have a bit of a play around with the ratio to get it as close as possible before applying it to the wider fountain.

Let me know if you have any further questions.

Jacob

parigi

Hey @JacobZ, I understand the oxide option, but I’m trying to avoid trial and error because it will be too time consuming. And if the fountain ends up looking patchy, my partner is going to have a fit. 😂

Ideally I’m looking to apply a coloured coat over the entire fountain to ensure its the same colour through out, and then seal it with a clear sealant. Or if there are coloured sealants that'd work fine too.

Again, appreciate the help!

JacobZ

Hi @parigi,

It's about the closest match you would be able to get to what is there, but I understand that it might not be a perfect solution.

When I say play around a bit, I mean make 2-3 very small mixes taking note of the ratio of mortar to oxide, then set them on something to dry overnight, then hold them up against the fountain and pick the one that is closest. If you took 5-10 minutes to do this on a Friday or Saturday, allowed it to dry overnight, then compared it and decided on the best mix, it wouldn't really be that time consuming.

Unfortunately, I am not aware of an off-white pond sealer that would be suitable, so it is about the best option I have for you.

Let me know what you think.

Jacob

parigi

Hey @JacobZ, thanks for all the advice! I'm gonna take it and start prepping to repair the fountain. Thank you again!

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