No roof vents

Looked at a house with zero roof vents and there were no visible AAV’s. The house was built in 2011 and is on a slab. There were no vents terminating in the attic. Assuming that there are AAV’s shouldn’t there be at least one main line vent thru the roof?

Did you look to see if there were any side wall vents?

The only side wall vents were for the tankless water heaters

Even if they used AAV vents there needs to be an exterior vent.

They are required to have at least one venting to the exterior.

AAV’S??? Cheater valves for drain?

I don’t understand. Are you talking about roof vents which condition the attic space or are you talking about plumbing stacks which allow air into the drains?

Yes, I had the same question at first. It appears to be the latter.

Me too!
But I did an inspection of a Metal Roof last week. New Construction and I think it is a good idea to have the “Plumbing Stack Vent” at the highest point out the side of the attic over the end gable vent. This way there is no penetration to the metal roof to deal
with.
I have also seen cheater vents in the attic but I would recommend at least one go to the outside whenever possible.

There are several jurisdictions in my area that allow for a “main AAV” that terminates in the attic, with no outside terminations.

The AAV will be either a 4" or 6" vent, but it is very obvious when you’re in the attic.