Possible Mold In Sandstone Around Pool

[JELLIS1000]

We have fairly new sandstone all around our pool and have just very recently noticed that there seems to be a few smallish areas that aren't completely drying out at all and have a hint of green in them, there seems to be a pattern as to the location that matches up with rain water coming off of the roof, we haven't currently got guttering but will be getting it soon, anyway, I have tried jet hosing the areas and also scrubbing with soap and water but they are still there, before I go back to the builders (its under warranty etc) and ask them to replace it, was wondering has anyone else had/have this, i'm assuming its mold in the stone??

Thanks

Jimmy

[Rimmer]

Can't get mold in the stone, that is simply rock, maybe on it.

You can not simply take up a square of sand wash then repair it by filling in the hole, the whole lot has to come up. You will have to find the root cause and fix it.

Sand washing is not easy, many contractors say they can do it but actually can not get the finish right, I assume you had a good contractor and the finish is smooth and has been acid washed.

Mold on sand wash pool edge could be from algae in the pool water splashing over? Is the pool properly balanced? Is the area in shade? Do you have sand washed steps in the pool? Do you have green spots on those? If the pool water is balanced correctly try scrubbing the green spots with that, I have used that method often to kill mold in grout in tiles around a pool.

Is the rainwater from the roof standing on the sand wash part of the day in the sun then in the shade?

I have an series of 6 sand washed steps close to the perimeter wall that has gone quite black with heavy mold. The steps are in the shade and were never finished properly with acid so the cement mix and zinc oxide color are still rough and have attracted mold. I can jet wash it off but don't bother much as It's not near the house. Have you tried jet wash?

[LennyW]

Jet wash off is the first step, even better if you can get a hot jet wash machine, once clean use a sealer product on the sandwash (same if you have these decorative sandstone panels), wont cure it 100% especially in shaded areas, but if you get it clean and then seal it, it will be very easily cleaned next time around.

Check out the Sika range of products at your local Home mart etc. (yellow containers with red writing) they have a very informative website too, just google "sika thailand" they have sealers specifically for sandwash.

Dont be holding too much faith in "going back to the builder" on this one!

PS edit to say.....dont waste your time till the rainy season is over!!

Edited October 16, 2009 by LennyW

[malcolminthemiddle]

Is the OP talking about sand stone or sand wash?

[xen]

Just mix a couple of scoops of pool chlorine in some hot water and apply. Use a broom to spread and minor scrub then leave for 15- 20 mintes and wash off

Just be careful of the fumes from the chlorine - don't breathe them in and don't let it splash on clothes etc.

U will need to do it as often as neccessary as it is not a permanent solution.

There are treatments that put a protective layer on the sandstone but they can be slipery and they do tend to wear in the high wear areas and end up looking bad.

I have found jet blasting/water blasting wears the stone eventually but is effective.

It also depends on the quality of the sandstone - and often pavers around a pool are "re-consituted Sandstone" (such as Haddenstone)which looks great but wear/chips/cracks very easily. if it is all you do is clean with the pool chlorine in that case.

[johnnyk]

Muriatic acid but be careful its nasty.

[katabeachbum]

Just mix a couple of scoops of pool chlorine in some hot water and apply. Use a broom to spread and minor scrub then leave for 15- 20 mintes and wash off

Just be careful of the fumes from the chlorine - don't breathe them in and don't let it splash on clothes etc.

U will need to do it as often as neccessary as it is not a permanent solution.

There are treatments that put a protective layer on the sandstone but they can be slipery and they do tend to wear in the high wear areas and end up looking bad.

I have found jet blasting/water blasting wears the stone eventually but is effective.

It also depends on the quality of the sandstone - and often pavers around a pool are "re-consituted Sandstone" (such as Haddenstone)which looks great but wear/chips/cracks very easily. if it is all you do is clean with the pool chlorine in that case.

second that

use gloves and glasses

if you have days with higher clorinelevel, poor some poolwater on the mold areas. could keep it away

I have yeat to see nicely protected sandstone. Looks like plastic even the clear silicone products on horisontal surfaces

Edited October 17, 2009 by katabeachbum

[lioness]

White vinegar will also clean any mould off, just brush it on, you can dilute with water to make it go further if you have a large area. Works the same as chlorine without the toxiditiy problems.

[slapout]

Bleach/ haiter works very good. Dampen area to clean with water, spay/pour bleach on area, broom to cover area, wait 15 minutes+ and wash off. Seems to work best if treated area is not allowed to dry prior to washing.