Question about EFFLORESCENCE in bricks and sealing options

lynny-jane · Aug 04, 2014 2:05 pm

Hi Guys,

I'm after a bit of advice with regards to painting over external bricks that are showing signs of efflorescence.

We are planning on painting the bricks with Wattyl Solarguard as we are after a more "Olde Worlde" gloss smooth finish rather than the more modern matte/gritty/sandy finish that a lot of specific brick coverage products give. Our local Wattyl paint shop doesn't know of or have any advice/products regarding undercoating/prepping the bricks. We figured that rather than rushing in and slapping the paint on without doing our homework on the potential leeching (if that's the correct term) through afterwards it was worth the effort.

Would really appreciate your input on this one......

Thanks,
Lyndall

jj1 · Aug 04, 2014 7:42 pm

will be watching any advice that is posted with interest, as we have the same problem on our front fence bricks. I give it the once over with acid when the mood moves me, but as we do not intend painting have not sought any further (permanent) treatment.

Stewie D · Aug 06, 2014 6:36 pm

I'm not an expert but my experience of efflorescence in brick and concrete walls is that it comes from two places - one from a combination of mixtures in the brick during manufacture and two from rising damp which sucks moisture and salts up from the ground which then comes out on the surface of the bricks. Two questions I have for you are
are your bricks the hard, fired at a high temperature sort or softer
does the efflorescence appear all over the wall or just above ground level ?

Stewie

lynny-jane · Aug 07, 2014 10:01 am

Hi Stewie,

Thanks for your reply. Here are a couple of photos of the offending spots - there are only two that we can see as the efflorescence is occurring on the inside of the brickwork. I'm not sure if our bricks are hard or soft....I could try throwing one at someone and ask them lol!! But seriously, we have a mixed bag of commons, all different colours. The efflorescence is happening up to about a metre high inside our fireplace and also on the inside garage wall....probably not a huge worry but I'm wanting to avoid possible development on the outside face later on and bubbling (not a Todd Carney reference) or flaking of our paintwork.

http://i1247.photobucket.com/albums/gg634/lynny-jane/bricksgarage.jpg

http://i1247.photobucket.com/albums/gg634/lynny-jane/bricksfirplace.jpg

Stewie D · Aug 07, 2014 12:52 pm

It sounds like you may have a defective DPC ( damp proof course ) which is usually installed just above ground level. Yours may be installed too low or it may have been bridged/compromised. Moisture being sucked up from the ground is either forcing salts out of the bricks or dragging salts from the ground with it which appears on the face of the brickwork. Efflorescence usually occurs on the lower parts of walls as a result. Old terrace houses and semis like those in Paddington see a lot of this where the old slate DPCs are either broken or missing. Brick repairers who specialise in this sort of work may be a good source of info. Someone with a moisture meter will be able to tell you whether the DPC is doing its job or not.

Stewie

Handy007 · Aug 11, 2014 9:30 pm

Stewie,

How much effect from poor draiange can have an effect like this?

StructuralBIMGuy · Aug 11, 2014 10:42 pm

Hi Lynny-Jane
Just curious is the outside wall
FaceBrick on the top half and rendered on the bottom half?
If so it should be the other way around.
Alternatively, Paint/Waterproof the whole external wall.
As stewie D said the moisture can only come from the Bottom or from the Top of the wall

Stewie D · Aug 12, 2014 9:45 am

Quote:

How much effect from poor draiange can have an effect like this?

Some or a lot but that depends mostly on whether the DPC is a) in the right place ( or the right level ) or b) whether it is intact.
You can have a DPC on a house that is in a flood zone with soaking ground and if it has been installed properly it will stop rising damp etc.

Stewie