How To Look At A House
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Why are most pull-down attic ladders not approved by building code for installation in a garage?
Monday, June 24, 2019
The wall and ceiling between an attached garage and the house living area is required to be minimum 1/2” drywall. Most garages have a ceiling secured to the bottom chord of the roof trusses or rafters, and that has to be 1/2” drywall also when the attic is continuous over the garage. There is a high incidence of fires started in garages due to the gasoline and other flammable materials often stored there and the intent is to create a barrier between the garage and house for fire protection.
But the way it is actually stated in the Residential Edition of the Florida Building Code is a “separation” between dwelling and garage, and as “not less than 1/2-inch gypsum board or equivalent. The International Residential Code (IRC) is similar.
Most homes have a 1/2” drywall panel installed in the attic access opening, which is fine. But when you put something else in the opening, it must be equivalent to 1/2” drywall, which has roughly a 20-minute fire resistance. The 1/4” plywood panel at most attic ladders does not meet that standard. There are several solutions:
1) There are fire-rated attic ladders on the market, starting at about $800 + installation. Not cheap, and they far exceed the equivalency requirement. Also, there are attic ladders that have had a rated fire-retardant applied to the plywood face, like in the photo below of a label on one.
2) Install a non-fire-resistant attic ladder somewhere in the house instead of the garage.
3) Some jurisdictions apparently allow modifications of the exposed surface of the ladder, such as applying 1/2” drywall to it or painting the wood with a fire-resistant paint. The application of 1/2” drywall seems like a bad solution because the unit will likely end up sagging away from the opening as the added weight overwhelms the closure springs—thereby creating an even worse situation of a direct opening in the attic. It will also probably void the manufacturer’s warranty. And not sure how verification of the fire-resistant paint on the surface of the ladder would be done.
Anyway, the one sure thing is that an off-the-shelf attic ladder from a big-box home improvement store in the garage ceiling is a definite no-no. But we see them pretty regularly.
Also, if you look closely at the photo at the top of the page, someone has also added a vent grille (for either combustion air or garage ventilation) in the ceiling that opens directly into the attic; yet another penetration of the required 1/2” drywall garage/attic separation.
For a more complete explanation of all the garage/house fire separation requirements, go to our blog post What are the code requirements for fire separation between an attached garage and the house? Also, see our blog post Does an attached garage that is only used for storage or as a workshop, and not for parking a car, still have to comply with building code requirements for a garage?
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