Pressure drop in attic ?
#1
02-15-23, 01:25 PM
Pressure drop in attic ?
I'm not sure I posted this in the right forum. It might belong under architecture or something.
This happened in my house years ago. I came home from work one night and noticed the attic hatch was open and ajar. It's not hinged or anything like that. I checked for signs of forced entry or wild animal intrusions. No signs of that.
There was a violent thunderstorm a couple nights before with 80 mph plus winds. Did this cause a pressure drop or vacuum in the attic through the vents? This attic hatch sits in a recessed cut-out in the ceiling. So it would have to lift this 2 pound hatch maybe 5 inches upward and cast it off to one side.
Is this likely what happened?
This happened in my house years ago. I came home from work one night and noticed the attic hatch was open and ajar. It's not hinged or anything like that. I checked for signs of forced entry or wild animal intrusions. No signs of that.
There was a violent thunderstorm a couple nights before with 80 mph plus winds. Did this cause a pressure drop or vacuum in the attic through the vents? This attic hatch sits in a recessed cut-out in the ceiling. So it would have to lift this 2 pound hatch maybe 5 inches upward and cast it off to one side.
Is this likely what happened?
#3
02-15-23, 01:48 PM
When this originally happened many years ago, I sent a few inquiries over the Internet but never heard back.
I immediately suspected this was the cause.
I immediately suspected this was the cause.
#4
02-15-23, 03:40 PM
Group Moderator
My attic access is in the garage. On windy days if the garage door is open the wind will lift the cover and often slam it down quite loudly. One of these days I'll do latches or something to hold it down...
#5
02-16-23, 11:48 AM
Wow. In my case, it's kind of hard to imagine the force of nature required to lift the cover upward and off to the side
in an enclosed structure.
in an enclosed structure.
#6
02-16-23, 01:02 PM
Group Moderator
It's pretty much the same force that allows a jumbo airliner weighing 100 tons to defy gravity and fly. Just by the difference created between high pressure and low pressure. (Aerodynamic wing shape and flaps) So when you think about it, a light attic cover isn't much weight. It's sucking air out of the house, which lifts the cover. Doors with no latches (outswing with hydraulic closers) can get sucked open in a similar way.
