# Maintenance of internal stone walls on old properties



## Cath Venn

We have an old property with a cellar which we have converted to a bedroom. On one of the walls we have noticed that a green dry form of mould/algae has started to appear. It's almost like a discolouring on the stone, it doesn't look like it has spaws growing. We don't know if it is safe and we don't what to use to get rid of it. We don't want to use harmful chemicals as it is a bedroom and would like suggestions as to how to remove it safely. Hope someone can help. Many thanks


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## Befuddled

I understand your concern about using chemicals on a bedroom wall but mould spores can be just as harmful. The problem will be caused by a combination of damp in the walls and lack of effective ventilation. You need to find out and remedy the source of the damp and then take steps to keep the air flowing through that room. Professional help maybe?


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## Cath Venn

Befuddled said:


> I understand your concern about using chemicals on a bedroom wall but mould spores can be just as harmful. The problem will be caused by a combination of damp in the walls and lack of effective ventilation. You need to find out and remedy the source of the damp and then take steps to keep the air flowing through that room. Professional help maybe?


Thank you for coming back, the source of the damp is because of the cellar is in bedrock, we have some ventilation coming in as we know we should not completely stop airflow but we also need to balance airflow with damp and cold so there is a fine balance to be made, and we will never be able to stop the main source. Do you or anyone you know have any suggestions of treatment? Otherthan than to get in a professional? Possibly the only option may be to apply a permanent waterproof sealant and then batten and plasterboard over, which would be a shame to cover the wall as it's a nice feature.


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## rynd2it

Cath Venn said:


> Thank you for coming back, the source of the damp is because of the cellar is in bedrock, we have some ventilation coming in as we know we should not completely stop airflow but we also need to balance airflow with damp and cold so there is a fine balance to be made, and we will never be able to stop the main source. Do you or anyone you know have any suggestions of treatment? Otherthan than to get in a professional? Possibly the only option may be to apply a permanent waterproof sealant and then batten and plasterboard over, which would be a shame to cover the wall as it's a nice feature.


I had a similar problem in our basement which has been cured by 'tanking' the inside with a compound usually used for building wet rooms. The wall were already rendered so no an appearance issue. We did investigate digging the soil away from the exterior of the wall and inserting a membrane but the work involved was far greater so the tanking option was used. If you can get to the outside of the wall, that's the best option.


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## boilerman

All sorts of solutions here, do these sound like you green mold?
green mold in cellar - Google Search

Btw, welcome to the site


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## Crabtree

I do not think that having a bedroom in a cellar is even permissible or sensible eg what about fire and escape routes?
As you have seen it can cause a lot of problems
Have you considered a VMC 








Tout savoir sur la ventilation mécanique contrôlée - Les ECO-Isolateurs


La ventilation est indispensable pour vivre dans un logement sain et confortable. Installez une VMC et respirez un air de qualité.




www.les-eco-isolateurs.com


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## MikeandEmilyD

Hi
I had a property in the uk with a similar situation. We spent a lot of money having it tanked and to be honest it was a waste of money. We couldn't even use it to store things in. After 12 months anything that was stored in there would finish up going mouldy even though we had electric fans put in to help airflow. What about using it as a wine cellar.


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## Crabtree

This may be useful including the requirement to consult the Mairie


https://www.travaux.com/construction-renovation-maison/articles/amenager-une-cave-en-piece-vivre-ce-quil-faut-savoir


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## Leforgeron

Cath Venn said:


> Possibly the only option may be to apply a permanent waterproof sealant and then batten and plasterboard over, which would be a shame to cover the wall as it's a nice feature.


Old stone walls need to breathe. Sealing them from the air may cause the chaux to deteriorate, potentially destabilizing the wall. Best to talk with a maçon who works with old stone houses.


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