# Black Stains



## minialice (Feb 29, 2008)

Hi, We have recently moved to central Portugal and we have black stains caused by damp/condensation on our ceilings. This is, in part due to the fact that the wood burner in the house didn't work and we now have a new one for next winter. In the UK my husband used Zinsser BIN to paint over the stains and to stop them showing through. We can bring some back with us on our next trip back but would like to paint the ceiling before that if possible. Has anyone used Xylazel Soluciones Pinture antihumedad - they sell it in Aki. We don't want to waste our money. Many thanks for any help.


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## baldilocks (Mar 7, 2010)

minialice said:


> Hi, We have recently moved to central Portugal and we have black stains caused by damp/condensation on our ceilings. This is, in part due to the fact that the wood burner in the house didn't work and we now have a new one for next winter. In the UK my husband used Zinsser BIN to paint over the stains and to stop them showing through. We can bring some back with us on our next trip back but would like to paint the ceiling before that if possible. Has anyone used Xylazel Soluciones Pinture antihumedad - they sell it in Aki. We don't want to waste our money. Many thanks for any help.


They are a form of mould/fungus. To start with you will need get rid of the cause of the humidity/damp. Once that is done, clean and rinse down with an anti-fungal solution - white-wine vinegar will kill the mould and tea-tree oil with help prevent more but you must ensure that the area is well ventilated (reduces the effect of the vinegar fumes on you) to dry the area rapidly. (Make a mixture of 2 parts distilled white vinegar and two parts tea tree oil, top up with six parts water. Shake well to ensure good mixing. Spray onto the affected area, leave for 20 minutes, respray; then wipe down and allow to dry thoroughly. If any mould remains after the initial anti-mould treatment, repeat until all of it has gone before painting with an anti mould paint. Make sure that the area is kept thoroughly dry and well ventilated. If the problem recurs- you may need to have the -plaster hacked off, the wall sealed with an anti-damp penetration seal (uPVA is quite good), then replaster.


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## RichardHenshall (Jul 26, 2009)

If it's black, it's almost certainly black mould. In my opinion you should endeavour to kill the existing mould first and only then cover the remaining traces. Otherwise the mould will continue to grow if there is any future humidity.

I have found the Henkel/Pattex Casa de Banho Sã Anti-Fungos spray to be very effective if, depending on the severity, applied neat (or slightly diluted with neat domestic bleach) spread using a normal paint roller. Allow to penetrate for 10 minutes or so and wipe dry with an old towel to help remove any remaining discoloration. Splashes of these chemicals will bleach/stain anything and everything, DAMHIKT.

Repaint with two or more coats of good emulsion, perhaps using a suitable additive such as Robbialac's aditivo anti-fungos e anti-algas as an extra precaution. Other similar brands are available.

Manage your condensation problem in future by use of heat, ventilation, insulation and de-humidification. For mould to grow you need mould spores, nutrients and moisture. The first two are everywhere, eliminating the third is the key.

Just before posting this I've read baldilocks' post. You will see that I take a more aggressive approach, though we are broadly in agreement as to the cause and avoidance of re-appearance.


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## minialice (Feb 29, 2008)

Thank you, we know what caused it and have cured the problem, we now just need to repaint the ceilings but didn't want to waste money on products here if they don't work as well as Zinsser BIN. We will look at the products you suggest.


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## RichardHenshall (Jul 26, 2009)

minialice said:


> Thank you, we know what caused it and have cured the problem, we now just need to repaint the ceilings but didn't want to waste money on products here if they don't work as well as Zinsser BIN. We will look at the products you suggest.


Assuming it's a sand/cement plaster, I would use an alkali-resistant primer to seal any localised bare plaster if there's any hint of rising or penetrating damp (which obviously needs to be fixed) to avoid problems from the salts. If it's purely mould fed by condensation, I've not found the need.


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