Recent content by oron

Thanks for the replies. Maybe I'm wrong, but isn't efflorescence light coloured stains and not dark ones as in my photos?

Hi, An elderly relative recently hired some builders to lay some new paving in her back garden. They finished the job yesterday and several of the paving slabs have marks on them as in the below photos (the marks in the middle of the slabs) She thought these were marks that would just...