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We where painting the fence and spilled some decking oil on the porch. We
used turpentine to clean it but it caused the cement to stain. Any ideas on how to fix this?
Hi @Engelah,
It is a little tricky to determine whether the white mark you are seeing is the turpentine reacting with the concrete itself or whether the turps has stripped off a sealer or coating that was originally on the surface. A quick way to narrow this down is to wet the area. If the concrete darkens back to the same colour as the surrounding slab, there is a good chance a sealer has been removed rather than the concrete being chemically bleached. In that case, a penetrative concrete sealer applied over the whole section may help even out the appearance.
Before you go that far, it is worth trying to clean the area thoroughly with warm, soapy water and a stiff-bristle brush. Sometimes the pale mark is simply residue sitting on the surface, and a firm scrub will lift it. If the scrub makes no difference and the spot still looks lighter once the concrete dries, the discolouration may be locked into the top layer of the slab. At that point, sealing the area may be the only practical option.
Please let me know if you have any questions.
Mitchell
