Best cleaner for black mould bricks

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Eva888

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#278500 19-Oct-2020 23:22

Any recommendations for a cleaner for old bricks which are porous and now black with mould. Last Spring used a waterblaster on them which looked great when first done but I now regret as it made the surface even rougher so the mould has permeated even worse. They are slippery and dangerous now after rain.

I don’t want a bleach based product which can hurt the plants and anything it touches and will also tramp into the house. I was thinking of using Vanish or Oxy Clean in a high concentration as a safer alternative. Has anyone had success with that?

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#2588051 19-Oct-2020 23:41

@Fred99 this might be up your brick lined alley :-)

eracode

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#2588058 20-Oct-2020 02:15

I have a similar DIY job to do for one of Mrs Code’s friends, once the Auckland garden hose ban has ended - but it’s a concrete wall rather than bricks. I’m going to use

https://www.wetandforget.co.nz/collections/outdoor/products/wet-and-forget

I’m going to mix it a bit more concentrated than the instructions say, spray it on then wait a while (say, 30 mins) while keeping it damp with the product before giving it a scrub it with

https://www.wetandforget.co.nz/collections/outdoor/products/deck-scrubbing-brush

Then rinse it off with the hose (certainly not water-blast it).

Then I’ll spray it again with the correct concentration and leave it for the rain to continue the work.

PS: IMO Wet and Forget products are overpriced for what they are. I’ll more likely find an equivalent spray product at Bunnings for 2/3’s the price and use that. I already have an equivalent brush.

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wellygary

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#2588066 20-Oct-2020 06:11

eracode:
PS: IMO Wet and Forget products are overpriced for what they are. I’ll more likely find an equivalent spray product at Bunnings for 2/3’s the price and use that. I already have an equivalent brush.

Unsurprisingly their competitors say exactly that too .....

https://30seconds.co.nz/why-pay-more/

tdgeek

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#2588071 20-Oct-2020 06:32

White vinegar will fix it, spray it on undiluted. Buy the cheaper Pams or a no frills brand. Id scrape it to help penetration, spray and leave overnight.

MikeAqua

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#2588084 20-Oct-2020 07:42

Vanish and Oxy Clean are oxidant's, like bleach.

Vinegar will work, but it's hard on the adjacent plants, being quite acidic.

Most things that will kill mould are hard on the plants.

Water a scrubbing brush and elbow grease will work and won't harm the plants.

Thinking out loud ... once all the mould is brushed off you could follow up with anti-fungal plant spray. It won't hurt your plants, but may kill off the residual mould cleaning leaves behind.

Mike

sbiddle

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#2588085 20-Oct-2020 07:45

You need an oxygen bleach based product if you don't want to harm vegetation. Most of the outdoor cleaners are based on this rather than regular chlorine based bleach.

While you can try making your own products and something like oxy clean may work fine the 30 seconds range of stuff is pretty cost effective, and sooooo much cheaper than Wet & Forget

tdgeek

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#2588086 20-Oct-2020 07:54

Dont spray on any vegetation! Or rub it on the bricks with a car wash brush. Ive read that bleach will kill it but on the top, whereas vinegar will take care of all of it

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Eva888

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#2588104 20-Oct-2020 08:58

I did pour some vinegar on one brick a while ago and it hardly made a dent. Brick was still black after a few hours. These are very old rustic bricks in a cottage garden and the mould is deeply imbedded so even when I scrubbed the indentations are still full of black and it didn’t budge. Between the bricks are thriving weeds whose death from anything other than round up would be welcome and each year it’s a mission to dig them out with a putty knife. The cracks between them have widened because tree roots are moving the bricks so seeds have a nice place to sprout. .

I looked up the 30 min stuff and the green label seemed the best as the blue had hypochlorite. Very cheap too compared to Wet and Forget. I wonder how long before you can walk over it as the bricks lead from the gate to the wooden veranda deck and front door.

MikeAqua

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#2588127 20-Oct-2020 09:59

When cleaning off fungus, bacteria algae etc. First you need to remove the bulk of material, then rinse away and then kill the residual cells/spores. For removal a good stiff brush with water and elbow grease will do the job. Then apply an active chemical like bleach, acid, virkon or a fungicide and leave it on.

Sadly, you will never win this war. The mould will keep coming back.

I'm slightly confused whether you do or don't want to harm plants among the bricks. If you are looking for a weed killer other than glyphosate (Roundup), there are a few natural alternatives (often based on plant oils) check out mitre10 or similar for options. I've had success with Hitman, works really well on hot days.

Mike

Eva888

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#2588151 20-Oct-2020 10:43

@MikeAqua Yes...I do want to kill the weeds in between the bricks. Thanks will look at Hitman.

timmmay

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#2588203 20-Oct-2020 11:13

wellygary:
eracode:

PS: IMO Wet and Forget products are overpriced for what they are. I’ll more likely find an equivalent spray product at Bunnings for 2/3’s the price and use that. I already have an equivalent brush.

Unsurprisingly their competitors say exactly that too .....

https://30seconds.co.nz/why-pay-more/

Unsurprisingly, 30 seconds is more expensive than required for many things as well. I used one of their products which worked well but was expensive, but the active ingredient was just bleach. So now I use warehouse bleach which costs about 80% less than 30 seconds.

I wonder if mould has gotten all through the bricks, and if it will keep growing regardless of what you do. I wonder if submersion in bleach for an extended period would help in that case. Note that I know little about this area, just wondering.

tdgeek

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#2588210 20-Oct-2020 11:24

Again, Ive read that bleach kills it but it wont kill whats deeper, vinegar does. Vinegar may not remove the black mould (i.e. be a cleaner) but it will kill it, and not just on the surface

tdgeek

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#2588226 20-Oct-2020 11:28

timmmay:

I used one of their products which worked well but was expensive, but the active ingredient was just bleach. So now I use warehouse bleach which costs about 80% less than 30 seconds.

You'd be surprised when you look into home remedies, you see bleach, vinegar, baking soda, hydrogen peroxide everywhere. Check the ingredients on the packaging, you often see them there also re general cleaning, etc

ratsun81

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#2588247 20-Oct-2020 12:05

What percentage Vinegar are you using? If you are only using 5% then getting the high strength stuff will work much better.

Search on trademe for high strength white vinegar.

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tdgeek

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#2588265 20-Oct-2020 12:15

ratsun81:

What percentage Vinegar are you using? If you are only using 5% then getting the high strength stuff will work much better.

Search on trademe for high strength white vinegar.

The standard solution which is 5% worked great for any solution I had for it. Mould, fungus, moss etc. Id be reluctant to use anything stronger on wood and concrete as it might start eating it too much.

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