Solvent used to dilute polyurethane coatings. Especially suitable for diluting the brushable polyurethane waterproofing membrane ISOFLEX-PU, when applied by spraying. It can also clean tools used for the application of ISOFLEX-PU and also tools from epoxy coatings residues. Additionally it can be used as a thinner for epoxy coatings. For polyurethane coatings SM-16 is added in a proportion up to 10% by weight.