Iv bought a karcher k4 pressure washer and need to price forvfirst block paving job.they normally doit themselves in an hour with round disk tool but want me to do it now.they are having trouble with weeds so need to know whats best way to get rid of them? Will they be gone for good? If not how long generally before treatment is needed again.how much should i charge for applying weedkiller then pressure washing? I live in yorkshire so cant charge southern prices.just saying incase your down that way lol thanks