I am bidding on a 300,000 square foot, galvanized metal roof, with a slightly pitched ribbed flat roof line. The roofing company is just needing it cleaned and they are going to put an industrial coating on it.  The roof is pretty clean, just a little grime and there are no types of units on top.

I am planning on using my double soft wash system to apply a little degreaser and bleach to cut the grime and then using my pressure washer to rince it all off with. I figure with 2 people spraying with the soft wash and 1 with the pressure washer, I should be able to clean 3000 - 4000 square feet per hour.

That should take me 75 to 100 hours to complete the job plus set up time. So i'm thinking that I need to be somewhere around $7500 - $10,000 for the job, but my gut tells me around the $9000 mark, I definitely want the job.

Any input will be helpful, this will be by far the biggest job that I have done. If my numbers don't look right, please chime in.