I think JWF did a good job fixing the blisters on and re-sealing my flat roof. Only time will tell . Initially, there were some hiccups trying to schedule a consultation, but they got the job done fast and at a fair price.They are very knowledgable and seem like an honest group .However, I've asked a few times to get a receipt and warranty for the work and still haven't received it two weeks after completion. I have no doubts that they would honor their work and warranty, once I am able to get in touch, though it is a bit frustrating and unprofessional.