In the interest of structural longevity, it’s usually preferable to tear off the old roof, particularly if insulation is wet or deteriorated, or if concerns exist with respect to the condition of the underlying structural deck. Naturally, a complete tear-off entails higher cost and often some inconvenience. However, if you should wish to investigate the feasibility of cost-saving overlay, Matthews technicians will be happy to evaluate the soundness of the existing construction, using non-destructive moisture detection instruments and to make sure such an overlay meet your city’s codes and restrictions.