Using bleach to remove moss from bricks...?

[berty3000]

Alright lads,

Some areas of the masonry at my house have thick moss on them, below the DPC. I assume this is best removed since it is probably feasting on the bricks. Or the effervescence maybe... anyway, one of the suggestions online is to use a 50:50 mix of bleach and water. This would be cheaper and perhaps more effective than these stupid weed and moss sprays that never work. However, bleach is also an extreme product. Could this solution damage my house?

Any other suggestions?

Thanks

 

[^woody^]

Moss does not damage brickwork, neither does bleach.

Bleach may temporarily kill some moss, but it's not long lasting. You would be better off using one of the proprietary cleaners such as Patio Clear, Bac 50 or Wet and Forget, as the chemicals in these hang around for a long time preventing re-growth.

 

[berty3000]

Isn't the moss drawing minerals out of the bricks or mortar, and couldn't its roots harm the brick?

 

[JohnD]

What can you do to rectify the excessive water?

Is the guttering, downpipe or gully leaking? Is the paving sloping towards the house? Post some pics please.

 

[^woody^]

Isn't the moss drawing minerals out of the bricks or mortar, and couldn't its roots harm the brick?

No minerals, no roots.

 

[berty3000]

No minerals, no roots.

So why is the moss living on the bricks then?

 

[berty3000]

What can you do to rectify the excessive water?

Is the guttering, downpipe or gully leaking? Is the paving sloping towards the house? Post some pics please.

Please see pics.

There's no leak. The DPC is two courses above the paving. The bricks get damp no doubt because they're below DPC.

It is a part of the house that does not get direct sunlight on it. It is also the only part where there is the hideous effervescence, which I've tried but failed to get rid of. There was a higher area of paving before last summer, one brick below DPC, which probably didn't help. But the most has appeared since that was all removed. Eaves are normal. It's a bungalow.

 

[JohnD]

There's no leak.

Visible, you mean.

The amount of long-term water is very evident.

Apart from the rainwater gully, what other sources of water are nearby? The garden tap?

Show us the other walls of the house.

Are the floors concrete? Are they damp?

BTW you say "moss" but I think it is algae.

 

[berty3000]

Visible, you mean.

The amount of long-term water is very evident.

Apart from the rainwater gully, what other sources of water are nearby?

What do you mean it is very evident, by the horizontal band of effervescence? I've just told you there was a higher paving surface there previously. Oh look! A corresponding course of bricks have been splashed for years on end.

There are no other sources apart from the gutter above (doesn't leak).

 

[JohnD]

What do you mean it is very evident, by the horizontal band of effervescence? I've just told you there was a higher paving surface there previously. Oh look! A corresponding course of bricks have been splashed for years on end.

There are no other sources apart from the gutter above (doesn't leak).

So just the rainwater gully and the garden tap.

 

[berty3000]

So just the rainwater gully and the garden tap.

Correct.

 

[^woody^]

So why is the moss living on the bricks then?

Because in moss terms, it's a nice place to live? As with all things property, it's location, location, location.

It looks like it's the joints not the bricks, in any case it's not as if the moss is sucking the wall dry of all nutrients and the wall will collapse in a few years.

The moss is living on the wall not off it.

 

[berty3000]

Because in moss terms, it's a nice place to live? As with all things property, it's location, location, location.

It looks like it's the joints not the bricks, in any case it's not as if the moss is sucking the wall dry of all nutrients and the wall will collapse in a few years.

The moss is living on the wall not off it.

fair comments.

Don't suppose you've any tips on how to get that unsightly effervescence off? I'm certain it's only there because of the older, high paving. None at all on the rest of the house. Or are there any ways to just disguise it that doesn't screw up breathability?

 

[^woody^]

It's dry brushing only for efflorescence I'm afraid.

It does not affect breathability.

 

[JohnD]

I'll try not to mention that yard gullies, their traps, and clay pipes attached to them, commonly crack and leak into the ground, causing damp.

By chance there happens to be one close to your wet patch.

Coincidence, perhaps.