Moss/algae on bottom of pebbledashed bungalow wall

Floozie

Has anyone any suggestions on how to get rid of moss/green algae which is starting to appear on the bottom of the bungalow wall next to the brick patio drive.  I was thinking of washing it with a bleach solution but am worried the bleach might affect the pebbledashing.

FreeBear

Bleach is alkaline, so shouldn't affect the render. It might leach a bit of colour out of any paint that has been applied, so test a small discrete area first.

Ebe_Scrooge

I tend to agree with FreeBear - bleach should be OK, but do a test patch first.  The other alternative that springs to mind is good old Jeyes Fluid.

canaldumidi

Just a thought, but why is it gowing there? Presumably the render at the bottom is damp. Splashback? What's on the ground at base of wall? Is there any sitting water? Blocked drain? Ground sloping towards the wall?

Alanp

There are various products available one being wet and forget, spray on and leave it to kill the algae 

Slinky

Is it a north facing wall? We used to get algae growing on our brickwork - it thrives in the shade. A good going over with a stiff brush removed most of it.

Floozie

canaldumidi said:

Just a thought, but why is it gowing there? Presumably the render at the bottom is damp. Splashback? What's on the ground at base of wall? Is there any sitting water? Blocked drain? Ground sloping towards the wall?

The bungalow is built on a steep slope with a block paving drive which runs alongside the offending bungalow wall and the sides slope down towards the bungalow wall (hope that  makes sense). We have had problems with a blocked drain previously  which runs down the length of the bungalow wall beneath the drive so I might lift the drain manhole cover and check there are no blockages - thanks for the suggestion. I will also try the bleach, Jeyes fluid, wet and forget and stiff brush methods and hopefully one of them will help!!!

canaldumidi

Floozie said:

canaldumidi said:

Just a thought, but why is it gowing there? Presumably the render at the bottom is damp. Splashback? What's on the ground at base of wall? Is there any sitting water? Blocked drain? Ground sloping towards the wall?

The bungalow is built on a steep slope with a block paving drive which runs alongside the offending bungalow wall and the sides slope down towards the bungalow wall (hope that  makes sense). We have had problems with a blocked drain previously  which runs down the length of the bungalow wall beneath the drive so I might lift the drain manhole cover and check there are no blockages - thanks for the suggestion. I will also try the bleach, Jeyes fluid, wet and forget and stiff brush methods and hopefully one of them will help!!!

So once you've cleaned the algae, you need to deal with the cause, both to prevent it recurring and to prevent penetrating damp internally.

Obviously any drain needs to be kept clear, but you also need to divert water on the slope away from the wall, ither by installing a French drain to capture the water before it reaches the wall, or altering the slope around the house, or someother barier to protect the wall from water.