Laying Landscaping Timber Project And Lessons Learned Using Mulch and Landscape Fabric 

Spray the area you want free of grass about a week or two before with glyphosate. Give it a second spray a couple days later. Scalp with mower, then place your "weed barrier" fabric down. Not sure if this was a job or your own place, but obviously if its a job you're not going to have the benefit of being able to properly killing off that grass. Even still, scalp it with a mower first and that should stress the grass enough that once you smother it with fabric and mulch it shouldnt be able to grow. Be forewarned, certain creeping perennial weeds like Canada Thistle will not be deterred by this either.

The wind noise is crazy bad. Otherwise good vid

Can rebar work with my hard clay in NW Ohio?

Wind noise killed the video

Bad fabric - that grass should not come though.