Mold on concrete and sandwash

[T_Dog]

Have some green and black mold appearing on our sandwash in patches. Planning on pouring on some bleach and brushing before hosing it off. Can I use the bleach full strength or should I dilute it? Ran across this archived thread that has some good advice.

http://www.thaivisa.com/forum/topic/149679-black-mold-on-concrete/page-2

[Iamemjay]

Dilute it 1:1 with water

[T_Dog]

Dilute it 1:1 with water

Got it done and it sure looks a lot better. Hardly any effort at all.

[Benmart]

Dilute it 1:1 with water

Got it done and it sure looks a lot better. Hardly any effort at all.

Glad it worked. I use a similar solution in the shower to keep the black mold in check.

[khunPer]

I found Duck Pro Bathroom from Mr. Muscle very good to clean both mold and dirt, also outdoor – better than the chlorine based algae and mold remover I used before. Dilute 1:1 or 1.2 with water. Eventuallt try with a small unimportant area first, to check.

[Cuban]

Certainly no expert on the construction side of things - but I speculate that if the concrete/sandwash is made with dirty water the chances for mold growth is greater surely?

Although any standing water (dips and hollows) or persistent drips will create the environment for mold to establish a home.

I would like more sandwash as I like it's non-slip nature, although getting a good "sandwasher" seems less than easy.

When I search for sandwash - I just get tips about softening silk or a suggested spelling correction about sandwiches!

[D Vince]

Certainly no expert on the construction side of things - but I speculate that if the concrete/sandwash is made with dirty water the chances for mold growth is greater surely?

Although any standing water (dips and hollows) or persistent drips will create the environment for mold to establish a home.

I would like more sandwash as I like it's non-slip nature, although getting a good "sandwasher" seems less than easy.

When I search for sandwash - I just get tips about softening silk or a suggested spelling correction about sandwiches!

I think what you guys mean is "exposed aggregate concrete"

[pest]

I found Duck Pro Bathroom from Mr. Muscle highly corrosive

it will ruin stainless steel and any other bathroom shower fittings if used neat

needs to be diluted

[manarak]

Don't use bathroom products on cement - these bathroom products are made for dissolving calcium, so they are corrosive to money minerals, and some contain acids, such as hydrochloric acid, which will corrode many metals.

Instead, just use bleach. 1:1 dilution means nothing unless the concentration is known. 5% concentration works, 2.5% works in most cases also.

The best is to power wash the area first and then to apply the bleach.

No need to wash it off, instead let it dry in, the effect will last longer.

[belg]

i went to makro and most big supermarkets chains here in thailand, never did i found pure bleech like you can buy in the gallon... any idea where it is sold in pure form ?

[StefanBBK]

I just used the good old pressure washer. Works perfect, just make sure to adjust the nozzle to spray wide, not pointed.

Sent from my GT-P7500 using Thaivisa Connect Thailand mobile app

[manarak]

i went to makro and most big supermarkets chains here in thailand, never did i found pure bleech like you can buy in the gallon... any idea where it is sold in pure form ?

There is chlorine sold in powder as a pool supply.

The normal haiter used for clothes is ok if you find nothing else.

[picoranton]

Remove mold, algea from concrete or any other surface, cheap effective and eco friendly!

Take let's say 5 liters of tap-water in a large bucket (this important as you will find out when adding the ingredients) add about 1 ltr vinegar (take the cheapest one which is basically acidic acid, no need for distilled vinegar) add to this 2-3 cups of baking soda (NOT BAKING POWDER) this will fizz quite a bit.

Stir this solution and apply to the molded surface and leave it for 20-30 minutes, than scrub, apply again when necessary, wash afterwards with water.

Advantages: cheap, fast and does not damage grout and cementeous surfaces! also deposal in your drain system does not harm, contrarry to bleach and cleaners based on nitric acid etc.

Even draining this into a sump or septic tank, as done in rural area's does not harm the system.

Now how can you prevent the mold and algea returning after cleaning? simple, take 1 ltr tapwater, a 9 V battery, a piece of wire and 2 silver coins or any 2 pieces of silver (spoon etc.) take a container 0.5 ltr, connect the wires to the silver coins,, hang the silver coins in the water, connect to the poles of the battery and let it run for about 30-45 minutes.(make sure the silver coins DO NOT touch each other in the water.(note sterling silver does not work because this is not silver.

This solution you apply after removing the mold on the dry area with a rag, this will keep your treated area clean for 3-4 month or even longer when outdoors and some sunshine

Of course this also can be used to remove mold from all other surfaces like bathroom, washing machine etc etc.

Try it and you will be amazed with results

[T_Dog]

Remove mold, algea from concrete or any other surface, cheap effective and eco friendly!

Take let's say 5 liters of tap-water in a large bucket (this important as you will find out when adding the ingredients) add about 1 ltr vinegar (take the cheapest one which is basically acidic acid, no need for distilled vinegar) add to this 2-3 cups of baking soda (NOT BAKING POWDER) this will fizz quite a bit.

Stir this solution and apply to the molded surface and leave it for 20-30 minutes, than scrub, apply again when necessary, wash afterwards with water.

Advantages: cheap, fast and does not damage grout and cementeous surfaces! also deposal in your drain system does not harm, contrarry to bleach and cleaners based on nitric acid etc.

Even draining this into a sump or septic tank, as done in rural area's does not harm the system.

Now how can you prevent the mold and algea returning after cleaning? simple, take 1 ltr tapwater, a 9 V battery, a piece of wire and 2 silver coins or any 2 pieces of silver (spoon etc.) take a container 0.5 ltr, connect the wires to the silver coins,, hang the silver coins in the water, connect to the poles of the battery and let it run for about 30-45 minutes.(make sure the silver coins DO NOT touch each other in the water.(note sterling silver does not work because this is not silver.

This solution you apply after removing the mold on the dry area with a rag, this will keep your treated area clean for 3-4 month or even longer when outdoors and some sunshine

Of course this also can be used to remove mold from all other surfaces like bathroom, washing machine etc etc.

Try it and you will be amazed with results

That sound more complicated than it needs to be. Using the bleach and letting it soak ten minutes, it was a rather quick clean up. If the mold comes back, another ten minutes and I am done.

[IMHO]

I have almsot 400sqm of sandwash at one of my properties, and in the wet season it needs cleaning almost every month.

As one other poster noted,a pressure washer make light work of it, and won't kill anything else around it. The pro's use watered down hydrochloric acid when cleaning them the first time after install, but this does also take some of the color out, and the run-off can potentially stain things like light color rocks, and kill gardens.

Best to just use high pressure water, and maybe just a *little* hydrochloric acid in the really tough spots if you've left it too long between cleaning.

[itchybum]

Remove mold, algea from concrete or any other surface, cheap effective and eco friendly!

Take let's say 5 liters of tap-water in a large bucket (this important as you will find out when adding the ingredients) add about 1 ltr vinegar (take the cheapest one which is basically acidic acid, no need for distilled vinegar) add to this 2-3 cups of baking soda (NOT BAKING POWDER) this will fizz quite a bit.

Stir this solution and apply to the molded surface and leave it for 20-30 minutes, than scrub, apply again when necessary, wash afterwards with water.

Advantages: cheap, fast and does not damage grout and cementeous surfaces! also deposal in your drain system does not harm, contrarry to bleach and cleaners based on nitric acid etc.

Even draining this into a sump or septic tank, as done in rural area's does not harm the system.

Now how can you prevent the mold and algea returning after cleaning? simple, take 1 ltr tapwater, a 9 V battery, a piece of wire and 2 silver coins or any 2 pieces of silver (spoon etc.) take a container 0.5 ltr, connect the wires to the silver coins,, hang the silver coins in the water, connect to the poles of the battery and let it run for about 30-45 minutes.(make sure the silver coins DO NOT touch each other in the water.(note sterling silver does not work because this is not silver.

This solution you apply after removing the mold on the dry area with a rag, this will keep your treated area clean for 3-4 month or even longer when outdoors and some sunshine

Of course this also can be used to remove mold from all other surfaces like bathroom, washing machine etc etc.

Try it and you will be amazed with results

That sound more complicated than it needs to be. Using the bleach and letting it soak ten minutes, it was a rather quick clean up. If the mold comes back, another ten minutes and I am done.

Depends if you care about all that crap going into the environment, the rives, the sea etc etc.

Most do not...so go ahead, join the ignorant.