green moss on brick work

[samtastic73]

Noticed this morning after being in garden for first time in a while (due to winter) that our new extension (2 years in April) has got a bit of white efflorescene on some of the bricks, which is fine I understand.

Have also noticed that just above an air brick/vent there is green moss growing on the pointing between the bricks. Is very localised to just above one air vent. Affects about 2 bricks up so. We have another vent about 2 feet away on the same wall but the brick around that is fine....

Is this anything I need to worry about? Is it normal? I'd appreciate some advice.

Thanks

Sam

 

[^woody^]

It's not abnormal, and can be left alone

 

[samtastic73]

is it preventable? The way the wall faces means it gets no direct sun - is this something to do with it?

Should I add that the air bricks are venting the roof space. They are not in the damp proof area?

 

[^woody^]

Moss will only grow on shaded north-facing surfaces. There can be several reasons why it starts in one place.

It may also take hold due to a slightly higher amount of water than the surrounding wall, but this can be a natural occurrence and not necessarily due to a defect

A photo from a few metres away showing the airbrick in context of the surrounding area may help

 

[samtastic73]

Untitled

• samtastic73
• 17 Feb 2013
• 1

The lower vent is the extractor fan from the cooker. The vent in question is the higher one. There is another air vent slightly higher and to the left just out of shot.

The wall is pretty much east facing / maybe east, north, east

Thanks for your help

 

[^woody^]

The verge (edge of the roof) does not have a wide enough over hang, and this allows water to run down the face of the wall instead of being cast off.

This makes the wall damper than it would, or should be, allowing moss to grow

The sleeve on the airbrick going through the wall, holds water in the bricks just above it too

 

[samtastic73]

Ok. That's good to know. Do I need to get the roof re-done, or just treat the moss regularly?

Is roof re-doing over-kill or sensible in the long run?

Thanks for your advice mate

 

[^woody^]

See my last line above, I clicked send too soon.

No need to mess with the roof now or the wall

A fungicide wash will clean it, but the moss may come back. Have a go if it is a problem.

 

[samtastic73]

I'm happy to treat it/ clean it now and again as long as I know it is not causing any long term damage etc. is a just a 'chalk it up to experience' and get cleaning every year job?

 

[^woody^]

Yes. But the more you do it, you end up with a clean white patch which stands out even more

If need be, spray it once and then a dry brush, in summertime when the wall is really dry instead