How to remove bird poo stains from concrete?

[r23on]

My question is how do i remove bird poo stains from concrete. image to come

[MitchellMc]

Looking forward to seeing those images @r23on. I'm sure they will help paint the picture for our helpful members, allowing them to understand the issue better.

Could you also tell us if the concrete is sealed or not, as that would be helpful to know whilst making product suggestions?

Mitchell

[Noyade]

My concrete is very old (>50 years) and not painted.

I usually blast bird faeces with a long pressure nozzle (to get really close) and if it continues to be stubborn - a light rub with a long wire brush.

Never had a bird turd that's beaten me yet.

[r23on]

Hi @MitchellMc 

first the concrete is not sealed so high pressure hosing is out of the question. The heat cooks it in. Being in Darwin puts another slant on this.

The stain a purple colour from the from a berry these pigeon like birds eat

Hope this helps I have use as large an image as possible. This is just a small are

[Jason]

Thanks for the photo @r23on. 

Let me tag @EricL who should be able to share his thoughts this evening. @MitchellMc will be back on the site on Friday.

There might also be ideas for you from this discussion kicked off by @Prof a while back - Removing stains from concrete.

Jason

[EricL]

Hi @r23on

I totally agree with your diagnosis. The bird poo gets cooked or carbonized into the cement making it next to impossible to get out. Have you tried @Noyade's suggestion? Does water blasting not work? What about using the wire brush? Does it have any effect on it? My recommendation is to try CLR 1L Calcium Lime Rust Remover and see if it breaks the bird poo down. It is very difficult to remove stains that have embedded themselves in the pores of a cement slab. My other suggestion is to use either Glitz 2L Premium Bleach or a diluted batch of Bondall 500ml Hydrochloric Acid. Please note that the last two chemicals mentioned are extremely dangerous. Please use proper PPE when handling.

If you need further assistance, please let us know.

Eric

[r23on]

hi @EricL 

the high pressure hose is out if the sealing that is applied by troweling is disturbed over time the concrete will begin to wash away and with the heavy rains of the wet season in darwin are quite heavy its very obvious here. I will give the CLR a go and I am not about to play around with Hydrochloric acid at this stage.