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Attached Garage Attic Access Pull Down Stairs

Jar,
Real common design on a ranch home. Drywall would be on the attic wall between the garage attic and the residence attic. Here it would be 5/8" type-x on that attic separation wall and the wall in the garage between the main residence, due to us amending the table.

Yep, see that too.
 
So according to Table R302.6 if you have an attic in an attached garage and the garage and house is separated with 1/2" drywall all the way to the roof you still need 1/2" drywall on the ceiling of the garage?

In other words you can't just have a plywood floor in a attic above a floor even when the garage and house is separated with 1/2" drywall all the way to the roof. Drywall still required on the garage ceiling?
 
Rick, you pose an interesting question my good fellow!

I do not see or interpret the code that you would have to drywall a garage ceiling when the wall between the garage going through the attic to the underside of the roof sheeting is dry-walled protecting the residence (example: ranch style house). It would be ugly as sin and may have conflicts with the energy code. I would like to know if this would be a correct interpretation?

Does the code allow a garage to have exposed ceiling joist?

It open up more questions, like do the exterior walls require insulation, are the other walls of the garage required to be dry-walled? Do you require the wiring to be covered or in conduit?
 
Happens all the time, no sheet rock installed on the garage walls or ceiling. There is no requirement to insulate a garage if it is unconditioned.
If you do not install sheetrock on the ceiling then you must install truss bracing across the bottom chord of the trusses every 10 feet. Check the truss drawings since I don't believe it is a code requirement
 
Don't know what energy codes have to do with it if the garage is not conditioned.

No problems with leaving ceiling joist or other walls without drywall except house side.

I'm just saying if the garage is already separated per code and you create an attic in the garage by putting in a wood floor on the top of the ceiling joists does Table R302.6 require you to drywall under the ceiling joists?
 
We amended the table to 5/8" Fire-X type rock from residence to attic separation.

We have too. We require 5/8 on ceiling and any wall that has the interior of the house on the other side, rated attic access if in the garage.

We have a lot of insulated garage, due to heat more so than cold and most builders install water heaters and softeners in a closet inside the garage, elevated at least 18" of course.
 
If stick framed, CJ's to garage beam connection will hold the CJ's at the on center marks.

If you do not install sheetrock on the ceiling then you must install truss bracing across the bottom chord of the trusses every 10 feet

Agree, yes trusses are required to have bottom cord bracing and is usually on the truss design paperwork showing locations.

I have seen some garages with Masonite hardboard with lattice over the seams.
 
FIRE-SEPARATION COMPLIANT STAIRS REQUIRED

The attic stair unit in the garage is required to be fire-resistance compliant or improved to meet the minimal separation requirements set forth in IRC R302.5 and R302.6:

R302.5 Dwelling/garage opening/penetration protection. Openings and penetrations through the walls or ceilings separating the dwelling and attics from the garage shall be in accordance with Sections R302.5.1 through R302.5.3.






Built-in folding ladders provide a convenient means of access to attic areas and are becoming increasingly popular for utilizing (unintended) storage space above garages. Unfortunately, people who install these ladders are generally unaware of fire separation requirements. Thus, with almost all of these installations, fire safety standards are inadvertently violated.



The partition wall between a house and an adjoining garage is typically covered with ½ or 5/8 inch drywall, to slow the spread of a garage fire to the dwelling. If the garage attic and house attic are not also divided by a firewall or fire-separation rated assembly, then the garage ceiling becomes part of the fire separation and must also be finished with 1/2 inch drywall. The access cover on a folding ladder is a mere sheet of ¼ inch plywood. When installed in a garage ceiling, this thin wood membrane replaces a portion of the fire-resistant drywall board, thereby breaching the required fire separation.



NOTE: The flame spread ratings for ½” gypsum board (drywall of Sheetrock) and ¼” Lauan plywood are not equivalent. The higher the rating the faster the material burns.



The rating for ½” gypsum board is 20
. See:

https://www.usg.com/content/dam/USG...eetrock-gypsum-sheathing-submittal-WB2380.pdf



The rating for ¼” Lauan plywood is 150. See:

http://sfm.dps.louisiana.gov/doc_woodproducts.html



Many, if not all, attic stair manufacturers sell units that will fulfill the fire separation requirement. The fire retardant plywood door panel is chemically treated to provide slower ignition, low flame spread, lower smoke production, and has self extinguishing features (burning ceases when ignition source is removed or exhausted.) Class A, or 1, pressure treated plywood is approved by building codes throughout the US for specific applications within fire resistant buildings as an equal alternative to non-combustible construction.



Memphis Folding Stairs, et al., advertises a "Firegard" option. FireGard® XF - Antimony Trioxide Flame Retardant.



To recap, a garage ceiling pull-down ladder is allowed by the IRC only under two circumstances: if the firewall is continuous above the ceiling separating the attic spaces between the garage and house, or if the pull-down ladder unit itself is UL-rated for installation in a fire-separation ceiling. IT CANNOT BE MADE ANY CLEARER.

There are roughly 7,000 fires in attached residential garages in the US every year. Do not become a statistic.
See: https://www.usfa.fema.gov/downloads/pdf/statistics/v14i12.pdf
 
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