Removing Green Algae(?) from an exterior wall.

54and56 · 20-02-2021 04:57PM #1

Hi all.

This is the view of my neighbours boundary wall about 1.5M (side passage) across from a window in my house.

Any suggestions for a permanent solution to remove it other than lot's of detergent and elbow grease?

fred funk }{ · 20-02-2021 06:22PM

Spray it with bleech and give it a quick scub with a sweeping brush. Leave for a few hours and rinse it off. It'll be all gone.

Car99 · 20-02-2021 06:34PM

Back pack Spray with a 10 to 1 mix of chlorine and water and just let it. It'll be back to clean in a bout a week.

54and56 · 21-02-2021 12:28PM

fred funk }{ wrote: »

Spray it with bleech and give it a quick scub with a sweeping brush. Leave for a few hours and rinse it off. It'll be all gone.

Thanks, I'll give that a lash today. Ongoing I don't want to remove the paint but as a once off this sounds like a plan.

54and56 · 21-02-2021 12:29PM

Car99 wrote: »

Back pack Spray with a 10 to 1 mix of chlorine and water and just let it. It'll be back to clean in a bout a week.

Thanks, this sounds like a sustainable option which won't damage the paintwork if the algae keeps growing back.

Is Chlorine something you can get in Woodies or similar?

21-02-2021 01:55PM

54and56 wrote: »

Thanks, this sounds like a sustainable option which won't damage the paintwork if the algae keeps growing back.

Is Chlorine something you can get in Woodies or similar?

Look for this. Sodium Hypochlorite

Car99 · 21-02-2021 02:06PM

54and56 wrote: »

Thanks, this sounds like a sustainable option which won't damage the paintwork if the algae keeps growing back.

Is Chlorine something you can get in Woodies or similar?

Any co op store will have it in 5 gallon drums. Farms use it for sterilising dairy units.

54and56 · 21-02-2021 06:17PM

Got this stuff in Aldi for about €1.50 which contains Sodium Hypochlorite. It's almost like gel so really covers the area it's squirted onto.

Gave the area a good dose of the "Power Force", left it for 2 minutes, scrubbed for 30 seconds with a yard brush, rinsed off with a hose and in 5 minutes Bob's your uncle, the unsightly green algae is gone!!

Thanks for the help.

The above might help someone doing a search for a similar problem.

listermint · 21-02-2021 06:30PM

Actually did mine today too. White render with green spots in places.

Just bought bleach in aldi and biological washing powder. Poured in some bleach poured in a cup of powder into my knapsack sprayer. Filled with warm water to top and sprayed around the house. Green was all gone in about 90 minutes. No scrubbing just sprayed and left it

Calahonda52 · 22-02-2021 04:09PM

listermint wrote: »

Actually did mine today too. White render with green spots in places.

Just bought bleach in aldi and biological washing powder. Poured in some bleach poured in a cup of powder into my knapsack sprayer. Filled with warm water to top and sprayed around the house. Green was all gone in about 90 minutes. No scrubbing just sprayed and left it

why the soap, for better surface adhesion?

22-02-2021 09:20PM

54and56 wrote: »

Got this stuff in Aldi for about €1.50 which contains Sodium Hypochlorite. It's almost like gel so really covers the area it's squirted onto.

Gave the area a good dose of the "Power Force", left it for 2 minutes, scrubbed for 30 seconds with a yard brush, rinsed off with a hose and in 5 minutes Bob's your uncle, the unsightly green algae is gone!!

Thanks for the help.

The above might help someone doing a search for a similar problem.

What are you doing at the weekend? I could do with mine being done as well if you're free

listermint · 22-02-2021 10:08PM

Calahonda52 wrote: »

why the soap, for better surface adhesion?

Why not? It smelled nice :P

But ya believe it held better to the wall for longer.

54and56 · 23-02-2021 10:04AM

SouthWesterly wrote: »

What are you doing at the weekend? I could do with mine being done as well if you're free

If only you were within 5km of me!!

rodge123 · 11-01-2024 10:13PM

https://www.boards.ie/discussion/comment/116360055#Comment_116360055

Dragging up an old thread I know, what ratio of water to bleach did you use? Seeing various threads saying 50/50 and others saying 10/1.

Front of house which is north facing is destroyed with green algae spots this year, never seen as bad…would usually just spot brush with mosgo but need to spray entire area this time. Not spending a fortune on mosgo if bleach will do as good a job!

listermint · 11-01-2024 10:32PM

https://www.boards.ie/discussion/comment/121604169#Comment_121604169

Probably more like 15 to 1 i use. I think anything less isn't really required.

rodge123 · 15-01-2024 10:20AM

https://www.boards.ie/discussion/comment/121604235#Comment_121604235

Got it done yesterday, does a brilliant job within a hour. No brushing or hose after needed.

How long before you had to apply again?

horse7 · 15-01-2024 10:35AM

How about a rusty stain on a wall from a dripping overflow pipe

listermint · 15-01-2024 11:13AM

https://www.boards.ie/discussion/comment/121617353#Comment_121617353

Maybe once a year, it depends on your boundaries (plant / tree growth)

phormium · 15-01-2024 11:20AM

I use 50/50 bleach/water, I find Supervalu is the only place I can get thin bleach, it's much harder to get a good even spray when using the thick gel stuff. I have a north facing boundary wall and I spray it maybe twice a year and it gets rid of the green.

SteelyDanJalapeno · 17-01-2024 12:53AM

Chloros from the coops is great, as with any bleach product, be super careful about splashes and it getting on skin and wear clothes you don't mind ruining etc.

Also be careful what you mix it with, vinegar and bleach can be deadly if inhaled

youtheman · 17-01-2024 07:42AM

Chloros is amazing stuff. I just applied it neat using a small garden type pressurised sprayer. No scrubbing or anything like that. Paintwork came up 'as good as new'. I did the whole house (bungalow) in a few hours.

phormium · 17-01-2024 10:13AM

Love the way it made a job of the path too!

Removing Green Algae(?) from an exterior wall.

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