The numbers of PVC-U windows, doors and conservatories in the UK, particularly in housing, is increasing rapidly. BRE has been investigating the effectiveness of hot air repair techniques on dents in PVC-U profiles, typically seen as a result of damage caused by a burglar. Hot air repair on PVC-U frames requires a high level of training and skill to produce satisfactory repairs. Where feasible, hot air repair is a more cost-effective and environmentally friendly solution than replacement. BRE trials on colour fastness of repaired profiles under conditions of artificial weathering indicate no significant effects on colour or gloss. 6 pages.