Cleaning outside slabs

[Heaven]

Our outside slabs have the green gunk on them. Has anyone tried cleaning them with Chlorine and if so what is the mix you use?

[Bert]

Best is to use caustic soda ( in my opinion) a fairly weak mixture leave it to soak them her wash. It may even come off with out using anything depending how bad. If you can’t find that use pool chlorine and about half a pond to a couple of gallons should do it. Soak and scrub or as I aid before use a Jet Wash

[snd1966]

The pool cleaner cleaned a customer's ceramic tiled patio area where the plant pots had overflowed in the winter and where bar b que fat had landed. it looked lovely BUT the top sheen was removed from the tile. I assume it would of been a pool chemical product.


Tim the window cleaner always used a different chemical in these areas when he used to clean the patio and the actual tile was never damaged so assume you can buy the correct product somewhere. Last year he cleaned a patio facing north, black with mould and at least 10 years build up and got the majority off a concrete based tile

[MVP]

Brush down with fairy liquid and water then jetwash does a pretty good job safely

[paul90]

I have been trying to clean the green algea from some of my slabs this week.
They are the normal 45cm x 45cm yellow/beige colour concrete slabs - also ten years old.

The green algea is easily removed using a pressure washer and water only.

However the pressure washer does remove the "coloured" top surface leaving the slabs a dull whitish colour.

Some of my slabs are covered in black spots of different sizes - these seem to be engrained algea which is too stubborn to be removed with my jet washer. Perhaps an industrial jet washer might help.

Chlorine does not help much but thick bleach diluted with water and scrubbed onto bad patches of green algea and then washed away is a standard method.

Does anyone know of a company who can clean the slabs with an industrial pressure washer?

[Bert]

Bleach is chlorine in liquid form albeit considerably weaker than the chlorine used here . Both chlorine and bleach have the same chlorites

[tutor4u]

Lemon juice

[13roman58]

Lemon juice

I know that there are a lot of lemons about now but how many would you need for a blackened tile
answer on a postcard to?

[tutor4u]

Probably about 3 lemons, put them in a blender, then put on slabs, use a broom to work juice in, wash off.

[Mollie the cat]

We just tried it, it actually works, we used about 6 lemons worked on about 2 square meters.

[Heaven]

Strange question, but you say put lemons in blender. Is that with the skins on?

[sticky1]

Can anyone recommend a supplier of power washers, east,west or south, and approx price of them.
Thank you

[Mollie the cat]

We just trod on the Lemons poured the juice on and used a wire brush, worked a treat, believe me our slabs were very pitted Black. Over all it took about 45 minutes to clean a large area, elbow grease needed but they look just fine now,

[Mollie the cat]

Cobam on the East side sells them, sorry no idea on the price, as you enter the shop they are on the right hand side,