Paving Slabs Cleaning

[joec1985]

Hello. I just had some riven flags laid. They are a charcoal colour but they have quite a lot of residual white stuff on them. I was just wondering what is the best way to get rid of this? I plan on using a sealer after I have gotten rid of all the dirt and grime.

 

[JohnD]

outdoors? it might be dissolved mineral salts coming out as they dry. New stone is damp with "quarry sap".

It will stop arising after a while, and weather away.

Washing with water tends to drive the minerals back into the stone, so brush off.

 

[r896neo]

The stuff on the cut flags against the wall is dust from cutting. Once wet it forms a residue that needs either a light pressure washing or a good stiff brush and hosing to shift it. The general boot marks also look like they walked in cutting dust from where they were grinding.

The obvious marks along the joint in the centre of the pic look like mortar stains and you will need removed with mortar acid. Really it is the paver who should be doing this work. Poor show to leave it like that and unjointed.

Lightly jetwash or scrub and hose it all. That will remove the cutting dust and if there is any marks left after that take a new photo with an overview shot and a close up.