# Removing Algae on concrete wall



## Black Sheep (10 Nov 2012)

We have a build up of algae on the concrete wall surrounding our garden. As we have recently painted the outside the house and replaced the driveway the wall is looking even worse. These is also a hedge just inside the wall and the pavement outside.

Anybody got any ideas how to remove this gunk as we may paint it later


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## asdfg (11 Nov 2012)

power hose


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## greengrass (11 Nov 2012)

spray a mixture of 1 part of bleach for 3 parts of water onto the moss/algae. Wait few days and clean/remove dead moss/algae.


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## Black Sheep (11 Nov 2012)

Thanks asdf but power hose is not strong enough. This stuff has a tight grip.

Greengrass thanks also and I'll try the bleach. Do you mean ordinary household bleach. I'd better get a gallon of it - long wall!!


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## sophie (11 Nov 2012)

Blacksheep, You could also give Jeyes Fluid a go, try a patch to see
if it starts to take it off and then you know where you are going.
I hate the look of it on the wall and it makes everywhere else
look terrible - good luck with the work.


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## salaried (12 Nov 2012)

Hi Blacksheep, I had a problem with algae also, With a patio not a wall and I tried different options, I would try the bleach option first , The thicker the bleach the better, If that does not work then the jeyes fluid might, Sophie and Greengrass are offering the correct advice, But if all else fails The only thing that worked for me was a product called moss-go, You can get one for moss or algae,The bigger stores like md o, sheas, woodies or b and q should stock this, It is not the cheapest one on the market but it is well worth the 40.00 euro I paid for it, You dilute it 1 part moss go (Moss go algae in your case) and 4 parts water and apply with your average watering can, You might need a ladder to do this in your case, You can only apply if we are due dry weather for 24 hours as it needs to set in and then let nature take its course  By that I mean the rain will wash it off for you, If it is very bad use a bucket and a hard brush to apply, Again the rain will do the rest, Best of luck.


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## greengrass (12 Nov 2012)

Black Sheep said:


> Do you mean ordinary household bleach. I'd better get a gallon of it - long wall!!


Yes, try a small patch first and see after few days.
It is best to do this when weather is dry as moss will absorb more of the fuild.


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## jackswift (12 Nov 2012)

You can buy a 5 liter drum of chlorus in any co op it's used for cleaning milking plants. Mix water with it and use a deck brush then wash it off.


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## Sandals (12 Nov 2012)

Wouldnt bother buying the expensive moss go, we did this for tarmac green moss, turned it black, powerhose does it for us after a good scrub with a little handbrush for yards.


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## PetrolHead (12 Nov 2012)

Just to add to the above, a power hose is ideal for washing walls but I've found using a patio cleaner keeps the mess down considerably. 

Google 'Karcher Patio attachment'


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## kbie (12 Nov 2012)

Glad to be able to add my input *'Black Sheep'* as you have helped me and so many others, and hopefully will continue to in the future, with your sound advice and experience in the past.

I have used MossGo and Hyperchlorine in the past to do the job you require and to be honest I have not had success with either. I find the power hose to be the most effective job with a flat spray of water. Make sure that the pressure is not too severe and start with a lower setting and work up. Also, keep the lance back from the wall initially and move closer if needed.

Good luck with the job!


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## Jazz01 (12 Nov 2012)

just a few things...

if you are spraying moss go / chlorous on the wall, wear eye protection... 

Also, be careful of "off spill" if you have a lawn / plants nearby... it will affect them...

Found deck brush, dipped in chlorous & brushed on, followed by power house worked well for me...


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## Black Sheep (13 Nov 2012)

Thanks to all for your suggestions. All I need now is a couple of dry days and lots and lots of elbow grease. The wall is 3-4ft high and over 100ft. long


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## franb (20 Nov 2012)

Power washer and it's a long long process, inch by inch, I find chemicals harmful at times.


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