Efflorescence on chimney breast

8 Jul 2013
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United Kingdom
Hi. If this would be better posted under a different section of this forum, please let me know. Am new to this forum stuff.

Have efflorescence on an internal chimney breast, about a metre above floor level. First discovered this about a year ago when hacking the plaster off the chimney breast to open up the chimney breast. I knew there was a moisture issue before I hacked off the plaster, as the plaster was damp, but the efflorescence had not appeared on the plaster itself, but after it was hacked off the crystals started forming.

I was aware the chimney stack was leaking and in need of repair, so assumed this was the cause of the moisture and the efflorescence. The stack has now been removed and we have had a new roof, which means water is no longer penetrating from above. This was completed in march. BUT the efflorescence is still occurring, four months later.

Does anyone know how long efflorescence occurs after the original source of moisture has been dealt with? Or is it possible the leaky chimney was never the cause?

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It can go on for months. A chimney stack can hold a lot of water. Just be glad it's not syrupy brown tar stains as well.
Presuming the leak has been resolved you need to kill off the salt now, scrap away the salt then wash the affected and surrounding areas with a water and vinegar solution about 4:1 ratio.
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