Lots of Silver Things
It does not look like a lot of work was done on the house the week of July 24-30, but we can see "lots of silver things" and a "tunnel," as Evan described it. Evan is seen here with his grandmother standing in the balcony area under the "silver things" also known as the beginnings of the duct work. In the second photo, you can see Tim putting in the pipes, also on the second floor, for the central vacuum. The second floor heating system is also seen in the right of the photo which includes the "tunnel."
Besides the duct work, pipes have been put in for showers, tubs, sinks, etc. and the roof shingles are almost done.