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How to clean and restore a limestone wall?

Just Starting Out

How to clean and restore a limestone wall?



I've been reading and researching about limestone walls, and got to confess I'm super confused on how to proceed.

I have a limestone wall (2 blocks tall) which is looking like could use some tender, love and care.


Behind this wall there's a quite big planter box, or garden if you will.


I would like to keep the stonish look and feel, although I want it to look cleaner and not call attention to it's defects and darker areas.


What options do I have for better look and feel?


Pictures attached.


Thanks in advance.




Making a Splash

Re: Limestone - How to bring it back to life

Hi @tfacchini ., great outdoor area you have there, i think the easiest way is to hit it with a decent pressure cleaner , that will work wonders with no chemicals, the black does come back eventually as the roots grow into the limestone.

It looks like the stone where your pump is stays a bit damp so that probably contributes to the problem

You can get a moss killer for it but once a year with the pressure cleaner will keep it looking tops

Bunnings Team Member
Bunnings Team Member

Re: Limestone - How to bring it back to life

Hello @tfacchini


Welcome to the Bunnings Workshop community. It's a pleasure to have you join us, and thank you for sharing your question about your limestone wall.


It's great that you've received excellent advice from @wooshka. Looking at the photos you posted, it seems that only the very end has been affected by moss and mould. I suspect this is caused by the corrugated roof covering that area and has concentrated the flow of water. This concentration of water has caused it to grow mould faster than the other parts of your wall.


I suggest trying out 30 Seconds 5L Outdoor Cleaner Concentrate in combination with Mr Clean Handheld Iron Scrub Brush. Please make sure to give the cleaner enough time to activate, once enough time has passed you can begin scrubbing the wall. When all the black stain has been removed rinse the wall with your garden hose. 


If you need further assistance, please let us know.




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Re: Limestone - How to bring it back to life

Hi  @tfacchini @EricL 


Your limestone dosnt look to bad a  little work it will  definatly get a new  face lift.


EricL suggested 20 seconds  clear concentrate. Well it is Sodium Hypochloride 1-5%  and Sodium Carbonate  basically a mould killer. and will take out the darker stains with a couple of applications most importantly it isnt acidic and  wont hurt the stone .


Can I also recommend  washing/cleaning  you tiles around the pool as I see a little dirt build up .  Ordinary dish washing soap and water  will also go along way to general cleaning as it is good for removing oily stains etc


If you wish to use a pressure wash as  @wooshka  suggested under 1000psi should be safe or simply dont go to close to  the stone will work with any pressure washer. Usually a house hold  hose on jet will do the  job too if you cant access a pressure washer like 

ERicL said.


I notice some extra  mortar on the limestone face so  consider I recently used an orbital sander 90 grit to polish  a  off  tile glue and mortar smooth  joints on a 2 tile high marble  wall to good effect so that is an option if some of those stains really stubborn I would finish off sanding with 240 grit just to give the  wall a little  extra smoothness.  Be carful  how much you sand and where you sand as you can form a depression or make one are  extra smooth which is  out of character to the rest of the wall.


The   best thing you can  consider doing next is  applying a natural  stone and paving sealer that dosnt make things slick it enters deep into the stones pores and  helps blocks  mold and alge regrowth. Or if it dose come back it  wont constantly  need you to to clean it as   deep or hard. 


Berger Jet Dry 1L Stone & Paving Natural Sealer  I/N: 1410034 


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