I have a customer who owns a large, abandoned industrial site (future development). Their only concern is in aesthetics. They would rather the site not look "overgrown". I did a gly./ammonium sulfate "burn" for all the weeds growing up through the cracks between the buildings and the immediately adjacent pavement/walks about 2wks ago. The results have been good. But, I'm concerned with the long-term efficacy. I've been reading about products such as Sureguard and Surflan. I informed my customer that the "process" would likely take 3 apps.. I have some areas that would be too expensive to treat with (Total guess, here....and I'll seek your expertise into a possible inexpensive PreM for grassy areas) a Sureguard/Surflan product. BUT, I'm thinking the cracks at the building lines would be a great spot for these products. Am I on the right track? +/- 4mos. residual efficacy (@ the building edges)? There are several thousand LF of areas to be controlled. I'm trying to do this as inexpensively as possible (naturally). Time lapse (quick-ness) of efficacy is not a concern. We're looking for long-term efficacy. I've searched for pricing on Sureguard. Lesco is through the roof. I'm just trying to get an idea on pricing. Thank you for your input.