Attaching garage to house: fire wall questions

Old 10-06-16, 03:34 PM
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Attaching garage to house: fire wall questions

I plan on building a garage which will be attached to the house. The wall of the house is of masonry construction and is about 9 1/2 feet high. The house sits on this wall and is of standard wood construction with vinyl siding. The garage will have an interior height from floor to ceiling of 8 1/2 feet and the floor of the garage will be about 7 inches higher than the basement floor. The gable of the garage roof will be attached to the house and the siding will be cut and removed to accommodate.The distance from the ceiling of the garage to the top of the gable will be about 5 feet.

My question is what are the firewall requirements. I do not plan on sheet rocking the ceiling of the garage if it isn't required. I also do not plan on installing an attic floor in the garage.

Do I only have to sheet rock the area above the ceiling of the garage and top of the gable? Or as an alternative can that exposed area be covered with sheet metal prior to attaching the rafters?

I assume no sheet rock is required on the masonry wall but correct me if I'm wrong.

I live in PA if that makes any difference.
Old 10-07-16, 02:39 AM
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Welcome to the forums Rich!

Local requirements are what you need to go by! and they can vary a good bit. The attic space above the garage needs to be sealed off from the rest of the house. This is usually done with firerock on the ceiling but sometimes with firerock [5/8" drywall] between the 2 attic spaces, occasionally by both. Your local permit office will tell you what they require.
Old 09-15-17, 07:57 PM
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Good answer by mark...

An 8" hollow cmu wall is usually rated as a 2 hr firewall, assuming no penetrations are made in it... no windows, pipes, ducts, etc. 2 layers of type X 5/8" drywall (fire taped joints) are also rated at 2 hours. But if your local code requires 1 hr, you would only need one layer of sheetrock, and yes, only on the wood framing. However if the drywall does not completely cover the block wall, a fire rated sealant must be used to seal the drywall layers to the block that also meets the hour requirement.

There may also be requirements for the type of door, it's fire rating, whether it must be out swinging or not, and whether it must have self closing hinges or not. All part of your local code... not something we could possibly know, but something you could find out with a phone call to your local building dept.

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