dried mortar marks

You can buy a brick cleaner - it is fairly corrosive so use it sparingly - but it won't remove huge chunks of motar. It will remove cement residue from the faces of bricks if applied with a stiff brush.

Martin

-- Martin J. Evans Wetherby, UK

Disclean

Why don't you get the builder back in?

The message from Martin Evans contains these words:

Anyone know what it does to slate?

No, I've not tried that but I did use mortar cleaner on my patio (which is a circle of coloured cement blocks) after my mother in law spilt a bottle of wood stain all over it and now that it has weathered a bit you cannot tell. You can always dilute it down and try it and increase the stength to see what happens. It is fairly corrosive but a good wash with water afterwards should ensure no lasting effects.

Martin

-- Martin J. Evans Wetherby, UK

So he'll have to come back and sort it out then won't he, even if he has to scrape every little blob by hand with a dremel.

Owain

Or a wire bush and some brick acid..

Lumps are removed with a rotary wire brush, pref in an angle grinder. Dremel also ok for small amounts. But use care, these will rip into bricks easily. Remaining film is removed with brick acid, which eats mortar for breakfast.

Dont delay cos the mortar gets harder as the days pass. Clean up should be done the next day.

NT

Wire brushes on brickwork will leave a visible metal sheen, or damage brick faces in the case of soft facing bricks.

their use should stop just short of the brick face, but as close as possible.

NT

Brick acid etches the metal dust too.

Then the chlorides just wash off.