Efflorescence on mortar = damp?

lg13mza

I noticed at the weekend some regions of the brickwork with efflorescence (see images).  I've got a very basic damp meeting and it does register areas of damp on the brickwork but it's very hit and miss and doesn't particularly help me track where the water may be coming from.  It's been cold but we haven't had any real rain for 3 or 4 days.  Is it something I should be worried about?  It's a cavity wall and nothing is presenting inside the bungalow..

FreeBear

Stop sticking that damp meter in to random parts of your house - The only material that it will give a worthwhile reading on is untreated timber. In anything else, the readings are worthless.

You have a relatively new build judging by the brickwork & mortar. A little bit of efflorescence is to be expected - The walls are exposed to the elements, so the odd bit of rain will draw out salts from the mortar from time to time. Absolutely nothing to worry about. If the discolouration bothers you, scrub the affected areas with a bit of white vinegar and wash down with clean water.

stuart45

It might be lime bloom, which looks similar to effloresence. Caused by free limes in the mix coming to the surface and becoming calcium carbonate.

cc58

We have an interesting issue but ours is inside our house. We've bought a house, painted downstairs and now there's efflorescence on one of the walls which wasn't there when we moved in on the old paint. Any thoughts?

lg13mza

FreeBear said:

Stop sticking that damp meter in to random parts of your house - The only material that it will give a worthwhile reading on is untreated timber. In anything else, the readings are worthless.

You have a relatively new build judging by the brickwork & mortar. A little bit of efflorescence is to be expected - The walls are exposed to the elements, so the odd bit of rain will draw out salts from the mortar from time to time. Absolutely nothing to worry about. If the discolouration bothers you, scrub the affected areas with a bit of white vinegar and wash down with clean water.

I appreciate your help, but I disagree that the readings are 'worthless'.  I fail to see what is wrong using a damp meter to show the difference between one area and another regardless of the substrate?

1st and 3rd image is a 5 year old extension.  The middle image is the original build that was late 80's.  It's also under a porch so shouldn't get any driving rain.

stuart45

Cavity walls get a certain amount of condensation in the cavity. It can run down to the bottom and out, or some may  hang around any mortar snots or mortar on the ties. This can cause damp areas in the wall which helps bring out salts or free limes in the joints. Salts are more likely to come from bricks, limes from the mortar.

floppydisk1

That '' damp meter '' readings are indeed worthless.  Basic damp meter reader - you mean little device with 2 little prong you stick to your wall - that is calibrated to measure how fast electricity gets from 1 prong to other and it is indeed only to be used on untreated  timber. Just to make a point - put it on say ... dry  metal door plate  or a long screw/nail - it will show you close to 100 % reading. Read other answers - they are correct. It ain't broken don't fix it, don't try to find an imaginary problem where there isn't one.