Efflorescence or frost damage?

[Scott Taylor]

Hi please can someone give advice on the attached pictures the conservatory must be 20 years old at least and we moved in about 4 years ago. Since we have moved in this white stuff has appeared on the bricks and some are starting to spall. I have no idea what’s causing it! We use the conservatory and have a fish tank and sofa in there. Our neighbour says that it wasn’t there before we moved in so I don’t know if it’s just bad luck or something we have done such as the conservatory not being well ventilated? We do have the windows open during the summer but not the winter. I even wondered if the water from the fish tank is evaporating into the bricks somehow any coming out as salts the other side? The wall seems in good structural condition. A bit of repointing is required at the top where the slabs join the bricks but I can’t see it causing it to that extreme. It’s only at the top of the wall and a bit less extreme in the middle but seems to be getting worse. You literally can’t brush it off either! Any ideas please?

Thanks
Scott

 

[Mottie]

I’ve got no idea but I’ve got exactly the same stuff on my front wall. I’ve been waiting since 2001 for it to disappear!

 

[Scott Taylor]

I’ve got no idea but I’ve got exactly the same stuff on my front wall. I’ve been waiting since 2001 for it to disappear!

It’s really strange no idea how to cure whatever it is that’s causing it !

 

[Mottie]

A builder once told me to use vinegar on it but I’ve never got round to trying it.

 

[^woody^]

A builder once told me to use vinegar on it but I’ve never got round to trying it.

That's just for bricks with chips

 

[^woody^]

It’s really strange no idea how to cure whatever it is that’s causing it !

It will be caused by excess water evaporating out.

So it’s either

1 - Faulty coping stones - loose, cracked joints or defective drips on the overhangs (moss in the groove?) causing water to soak in to the wall

2 - Years of prevailing weather and then finally salts get near the surface to be visible, or more recent extreme weather events bad enough to bring the salts out.

3 - Defective pointing

4 - Or your fish tank theory with moisture getting in the cavity and then evaporating out nearer the cooler top of the wall.

1 or 2 are the most likely.

Either way, check the copings, but otherwise you can dry brush it but there are no other treatments that will work. It’s unsightly but not detrimental.

 

[Scott Taylor]

It will be caused by excess water evaporating out.

So it’s either

1 - Faulty coping stones - loose, cracked joints or defective drips on the overhangs (moss in the groove?) causing water to soak in to the wall

2 - Years of prevailing weather and then finally salts get near the surface to be visible, or more recent extreme weather events bad enough to bring the salts out.

3 - Defective pointing

4 - Or your fish tank theory with moisture getting in the cavity and then evaporating out nearer the cooler top of the wall.

1 or 2 are the most likely.

Either way, check the copings, but otherwise you can dry brush it but there are no other treatments that will work. It’s unsightly but not detrimental.

Thanks very much for the detailed reply. The mortar near the copping stones does need repointing so I will start there and see what happens. Thanks for the reassurance though I do appreciate that.

One last question. What would of caused some of the faces of the bricks to spall? They just starting to come off slightly at the top if you can see in the picture? I have tried a wire brush to get it off but no luck. I take it using a sealant paint wouldn’t be any good?

 

[^woody^]

Frost. Probably assisted by excess water in the brick, but could just be because that type of brick is susceptible to frost attack anyway - especially in that exposed location.