atypical fire separation breaches

[Robert Foster]

Take a look at this attached garage that I believe was built as part of the original house in 1987. I'm wondering if all three of these openings increase the speed at which flames would spread.

The attic above the garage is accessible from the second floor hallway as a walk in through a standard interior grade wood door. Also some of the paper faced fiberglass batt insulation installed in the interior walls separating the second floor rooms from the attic is installed backwards leaving the paper face exposed. Obviously these details would allow a fire starting in the garage and gaining access to the attic to spread far quicker than common sense and current building codes would like. This obviously warrants being called out but I'd like to know what other inspectors think about each of these three openings taken individually.

1) I've never seen a window into a garage before, the window is in a bathroom. Does fire spread more quickly through a tightly closed window than through 1/2 inch sheetrock or a 20 minute rated door?

2) That's a whole house fan installed in the garage ceiling, which I've never seen either. Does fire spread more quickly through a tightly closed metal louvered grill than through 1/2 inch sheetrock or a 20 minute rated door?

3) The frequently seen attic pull down stairs.

[Ted Williams]

Garage Fire Wall / House and Attached Garage Separation Wall (http://www.checkthishouse.com/744/garage-fire-wall-separation-wall.html)

[Darren Miller]

As far as I know, #3 was never in the IRC.

[Jerry Peck]

Take a look at this attached garage that I believe was built as part of the original house in 1987.

1) I've never seen a window into a garage before, the window is in a bathroom.

I suspect the garage was a carport and was enclosed later.


Does fire spread more quickly through a tightly closed window than through 1/2 inch sheetrock or a 20 minute rated door?

Yes.


2) That's a whole house fan installed in the garage ceiling, which I've never seen either. Does fire spread more quickly through a tightly closed metal louvered grill than through 1/2 inch sheetrock or a 20 minute rated door?

Most definitely yes.


3) The frequently seen attic pull down stairs.

The pull down stairs also violates the minimum 1/2" gypsum board separation requirement and needs to be covered with 1/2" gypsum on the garage side. I just wrote two of these up today on new houses and explained to the contractors that these need, at a minimum, to be covered with 1/2" gypsum to maintain the separation between the garage and the house. The builder who usually grumbles about having to do things he has never had to do before said: "I never thought about that, yeah, I see what you mean.", then asked about a way to accomplish it and give a finished look so the edges of the 1/2" are not showing (I suggested that one way would be to install 'J' trim around the perimeter of the pull down stair cover and then install the drywall up into that area, finishing the drywall off to the 'J' trim).

The way to correct for the window is to remove it, but that bathroom would then likely need more mechanical ventilation.

The way to correct for the attic fan louver is to remove it all and close the ceiling up with drywall.

[Robert Foster]

Thank you Jerry.

I first suspected the carport idea too, but couldn't find any indications anywhere to support that theory. Then I remembered that in 1987 there were virtually no inspections in my area and as far as building goes it was like the Wild Wild West around here.