I wonder if not having a permit to work on the wall repairs in the first place has anything to do with this.
I mean, the alibi is absolutely ridiculous from start to finish. I don't know of any contractor who would drive a couple of hours away and rent a hotel room the day before the supposed wall was to be repaired.
If Barry were so prepared and arrived in advance, you'd think that he'd have all his ducks in a row...Permit, supplies, tools, people well in advance...
As I see it from an outsider's POV, this was an alibi thrown together at the last minute to distance himself away from a crime/crime scene. I mean, he couldn't be home with no wife when the girls arrived. Then, he'd have to say that he saw Suzanne leave on the bike trip...
JMO.