Any moss removal experts?

[greyvix]

We have moss on our newish extension. They are hand-made bricks and I don't want to damage them with anything too acidic. It's at the bottom of the wall. Any ideas?

[PigletJohn]

moss means that it is wet. You say it is new build. Does water drip off the roof or out of the gutter, and splash off the ground onto the wall?

Or is there an outdoor tap, hose, or possibly a water leak? Or does the paving/ground slope towards the house and cause rain to run to it?

There is a chemical called Armatillox (sp?) that you can order from roofing or garden suppliers.

[magimedi]

Most garden centres will have Armillatox - it is amazing at removing moss & slime from bricks, paving decking etc & moss from lawns. It is totally safe to use, does not harm pets or wildlife but does have quite a strong smell.

PS I don't work for the makers!

[Lanabelle]

I blast the moss off our paths with the karcher pressure washer. works a treat, makes a wee bit of a mess and its quite satisfyingly fun actually

[greyvix]

Pigletjohn, it is the bricks below the damp course. We do have shingle at the edge of the patio- between the paving and the wall. The patio is also quite high, we raised it to make it level with the lawn. Still below the damp course, however.

[PigletJohn]

could the paving be sloping towards the house?

experimentally, dig out some of the shingle and see if the ground is unusually wet.

If you can dig a french drain, it will help the wall to stay dry. Green bricks are abnormally wet, so there could still be a problem with a downpipe or something. You may need to have a look during heavy rain.

Handmade bricks are usually soft and absorbent, so may spall in frosty weather.

[greyvix]

What is a french drain?

[greyvix]

Also, Armillatox appears to be out of production at the moment. Is there anything similar anyone has experience of? Thanks.

[yourlittlesecret]

Biological washing powder kills moss. I sprinkled it all over my moss covered patio and within 3 days it was dead. I dread to think what it has in it

[greyvix]

Thanks. Did it leave a white mark? I don't want to damage the bricks!

[PigletJohn]

A French Drain is a trench which is filled with pebbles or other small stones. The fill prevents the sides from collapsing like an open drain, and means you can walk on it without falling in.

It works like a drainage ditch. The pebbles prevent water creeping up from capillary action.

It is often used around the walls of buildings to prevent water making the walls damp. It should be angled slightly so that any water does not collect, but runs away to a convenient place. The trench can be lined with landscape fabric to prevent mud, silt or soil particles leaking in and choking it.

[greyvix]

I think that is what we have. I am going to ask the patio man to come and check it. Thanks for the advice.

[PigletJohn]

having been mulling it over, I reckon your shingle trench is holding water. Actual moss does suggest the bricks are abnormally wet, and even "rising damp" cannot usually be made to go up more than two courses of brick, even on brick bridges that are standing in rivers.

Maybe it is not draining away (e.g. clay soil or concrete underneath, or does not continue downhill) or maybe too much water is delivered to it (e.g. paving slopes towards house, or a gutter or waste pipe is leaking).

It would be interesting to take a trowel to the shingle and scoop a bit out and see if it is watery underneath.

If you are on sloping ground, perhaps it could be led away down the side of the house, or even into a flowerbed to soak away.

[greyvix]

Thank you; I appreciate the advice. We have dug out the shingle today. It is damp, but not sitting in water. The extension does not have guttering, and so the water runs off the lead topped pediment to the ground. Do you thing that is causing the wet bricks? The trench (without gravel) is free draining it appears.

[PigletJohn]

'mmmm

if there is no gutter and no downpipe going to a drain, water is going to run off the roof and drip or splash up onto the wall.

that could well be the cause of the wetness.

go out on a rainy day and you may see it happening. Leaking pipes and gutters often cause green algae on the wall below.

Are you in the UK? I have seen houses in Canada with very wide eaves and no gutter, I think because of the snow, though snowy mountain houses in Italy have metal gutters and downpipes.