Engineering bricks exhibiting slight efflorescence which I 'm assuming
is an alkaline calcium compound, maybe calcium carbonate ?? I want to
paint over them using masonry paint. The bricks are inside a
conservatory. The efflorescence appeared during the drying process, the
brick wall is now dry and protected from the weather.
Would it be in order to paint over the efflorescence or would it be
better to remove it using the usual hydrochloric acid before painting.
I am mindful that masonry paint is formulated to cover cement based
renderings (alkaline) so it's likely that it would not be happy with an
acid impregnated surface despite repeated washings.
Also I do not want to introduce acidic fumes inside the conservatory as
hydrochloric is very volatile in my experience.

What does the team think?
Don

On Thu, 17 Jun 2010 08:34:54 +0100, Donwill
wrote:

Engineering bricks exhibiting slight efflorescence which I 'm assuming
is an alkaline calcium compound, maybe calcium carbonate ?? I want to
paint over them using masonry paint. The bricks are inside a
conservatory. The efflorescence appeared during the drying process, the
brick wall is now dry and protected from the weather.
Would it be in order to paint over the efflorescence or would it be
better to remove it using the usual hydrochloric acid before painting.



There is no need to use brick acid. Just brush off the efflorescence
and apply the paint.

If you fear that the efflorescence has not yet stopped, and is still
coming through, this is unlikely, but a salt neutraliser will help to
reduce the risk of its reappearance:

http://tinyurl.com/3xv54re
or:
http://www.dampness-info.co.uk/damp%...altneutraliser

On Jun 17, 8:34 am, Donwill wrote:
Engineering bricks exhibiting slight efflorescence which I 'm assuming
is an alkaline calcium compound, maybe calcium carbonate ?? I want to
paint over them using masonry paint. The bricks are inside a
conservatory. The efflorescence appeared during the drying process, the
brick wall is now dry and protected from the weather.
Would it be in order to paint over the efflorescence or would it be
better to remove it using the usual hydrochloric acid before painting.
I am mindful that masonry paint is formulated to cover cement based
renderings (alkaline) so it's likely that it would not be happy with an
acid impregnated surface despite repeated washings.
Also I do not want to introduce acidic fumes inside the conservatory as
hydrochloric is very volatile in my experience.

What does the team think?
Don

fairy liquid and vinegar brushed on, dry, paint

Jim K

Jim K wrote:
On Jun 17, 8:34 am, Donwill wrote:
Engineering bricks exhibiting slight efflorescence which I 'm assuming
is an alkaline calcium compound, maybe calcium carbonate ?? I want to
paint over them using masonry paint. The bricks are inside a
conservatory. The efflorescence appeared during the drying process, the
brick wall is now dry and protected from the weather.
Would it be in order to paint over the efflorescence or would it be
better to remove it using the usual hydrochloric acid before painting.
I am mindful that masonry paint is formulated to cover cement based
renderings (alkaline) so it's likely that it would not be happy with an
acid impregnated surface despite repeated washings.
Also I do not want to introduce acidic fumes inside the conservatory as
hydrochloric is very volatile in my experience.

What does the team think?
Don

fairy liquid and vinegar brushed on, dry, paint

Jim K

AIUI these salts are water soluble, so any liquid is likely to drive
them back into the bricks whence they came. A dry brush would seem to be
the best solution.