I need some concrete experts’ help.  I am a general contractor working in the desert southwest with limited concrete experience.  We recently poured a stamped patio for a customer that we colored and sealed.  Let me give you the timeline. <!—-><!—-><!—->

1) Poured the patio in early November.  Finished the pour on a Wednesday, cleaned, colored and sealed the patio on Friday with a water based sealer.  However, between the cleaning and the first coat of sealer, there was a light sprinkle that lasted about five minutes.  The concrete sub waited for the patio dry before they applied the first of two coats of sealer.  Looks great, exactly what the customer wanted.  Everybody’s happy.<!—-><!—->

2)  The following Tuesday, a steady rain turns the entire patio a milky white color, slick like an ice rink, and washes most of the “milk” off the patio.  After it dries, color looks awful.  Concrete sub says they will clean and reseal the patio.<!—-> <!—->

3)  Two weeks ago concrete sub power scrubs and power washes the patio, allows 24 hours for it to dry at my insistence.  The next day they apply two coats of sealer, patio looks great and everybody is happy.  Sub wants to paid, but customer wants to test the sealer first to make sure it doesn’t happen again and asks how long it needs to cure.  Sub says seven days.<!—-> <!—->

4)  We have rain this weekend and some area’s of the patio turn slightly milky again.  However, there are other areas that the water beads up like a freshly waxed car.  Now the sub reverses himself, says it is a “sacrificial†sealer and that is to be expected when it gets wet.  If we leave it alone and stay off of it when it is wet, it will dry and be fine.  <!—-> <!—->

I need to know about these water based sealers.  His recommendation from the beginning has been that the customer should try to avoid using the hose to clean off the patio, instead to use a blower.  The hard water we have could be damaging to the sealer.  I don’t have the expertise about concrete sealers to know for sure what to think.  I have done what research I can online, but most of what I can find refers to the milky color during application, nothing after application.  Obviously, there is a problem and I believe it lies with the sealer (and the sub).  I think it is ridiculous to tell a customer that they shouldn’t walk on their patio when it is wet.  Any knowledge you can pass along would be greatly appreciated.  Thanks<!—-> <!—->