Does attic panel in garage ceiling need to be sealed?

[Tom Cissell]

New build construction - one story house. Attic over garage is open to attic over the house. Access to the attic is through a panel in the garage ceiling. Is there any requirement for that panel to be sealed to either maintain fire resistance or fume penetration? Since there is no living space over the garage I could not find any requirement for this but it seems like fumes could migrate to the attic space over the house. Is this an issue? Thanks for the help.

[Alton Darty]

This is a topic that comes up here on a regular basis and there are tons of posts on the subject.
A search will reveal more than you would care to read on this but the short answer is that the opening most likely defeats the fire separation. At the least the ceiling panel should be sheetrock or other non-combustible material. No requirement for sealing the panel for fume penetration that I know of, but different areas will vary on requirements. Check with the Authority Having Jurisdiction for local requirements.

[Tom Cissell]

This is a topic that comes up here on a regular basis and there are tons of posts on the subject.
A search will reveal more than you would care to read on this but the short answer is that the opening most likely defeats the fire separation. At the least the ceiling panel should be sheetrock or other non-combustible material. No requirement for sealing the panel for fume penetration that I know of, but different areas will vary on requirements. Check with the Authority Having Jurisdiction for local requirements.

Thanks Alton.

[Jerry Peck]

Not only is the attic access cover in the garage required to be minimum 1/2 inch gypsum board, if the inspector has their thinking cap on the inspector would not approve the cover being supported in the opening on wood trim.

Wrap the inside of the framed opening with 1/2 gypsum board to support the access cover.

Wood trim does not meet the 1/2 inch gypsum minimum requirement.

[Vern Heiler]

Not only is the attic access cover in the garage required to be minimum 1/2 inch gypsum board, if the inspector has their thinking cap on the inspector would not approve the cover being supported in the opening on wood trim.

Wrap the inside of the framed opening with 1/2 gypsum board to support the access cover.

Wood trim does not meet the 1/2 inch gypsum minimum requirement.

Good idea Jerry. Have you seen this done?

[Jerry Peck]

Good idea Jerry. Have you seen this done?

Quite often ... (which indicates that I am not the only inspector in the state who catches that ).

Also, I must admit that I had not thought anything about it until a few years ago when I saw where other inspectors were requiring it - that is when it hit me that when the wood trim burns and/or falls loose, the 1/2" gypsum attic cover is now laying on the garage floor ... where does not serve any real purpose.

[Vern Heiler]

Quite often ... (which indicates that I am not the only inspector in the state who catches that ).

Also, I must admit that I had not thought anything about it until a few years ago when I saw where other inspectors were requiring it - that is when it hit me that when the wood trim burns and/or falls loose, the 1/2" gypsum attic cover is now laying on the garage floor ... where does not serve any real purpose.

The AHJ"s in this area have been requiring 1" nominal as the trim instead of the door molding that is often used. I had never thought of lining the opening with drywall and doubt that they have.

[Marshall Brown]

Although it is always a good idea to be aware of code issues that might help us perform the most informative inspection we can, you can use a little reason to see the issues here.

Rising fumes from a garage space shouldn't be in the attic space but in newer properly sealed homes there is little air leakage from the living space to the attic and what there is would generally be from the living space into the attic space not the other way round. In the winter the heated area would tend to force air from the living area (higher pressure) to the colder attic space. In the summer the attic space would tend to force its hot air up through the vents to a relatively cooler exterior sucking air from the living space upward too.

The real problem comes as the result of a fire in the parking area. The air temperature could easily exceed 1500 degrees F in just a few seconds. The hot flames would quickly consume any flammable material used for the hatch or its supports (You have to love pull down stairs with their 1/4 plywood attic hatch cover.) The rapidly expanding heated air would exert enough force to blow any poorly sealed hatch right into the attic on its way to the roof venting.

Once the flames are in the attic a new set of problems rapidly arise. Fiberglass insulation will melt at about 1300 F, the paper on the drywall back side will start to go at about 451 F (Thanks Ray Bradbury), the gypsum will off gas most of its water and start to crumble into the house living area.

The codes are written to avoid tragedies like this from happening but it never hurts to think about the why of the situation.

My opinion is that any and all openings from a parking area into other parts of the structure be sealed with a fire rated sealant and that hatches or other access' be designed to seal tighter under pressure rather than be allowed to lift. I like a drywall cover 4" larger than the opening all the way around firmly screwed in place.

Sorry for the long winded reply but I had some friends that barely survived a garage fire sequence as described above.

[Jerry Peck]

The codes are written to avoid tragedies like this from happening but it never hurts to think about the why of the situation.

My opinion is that any and all openings from a parking area into other parts of the structure be sealed with a fire rated sealant and that hatches or other access' be designed to seal tighter under pressure rather than be allowed to lift. I like a drywall cover 4" larger than the opening all the way around firmly screwed in place.

Actually, codes are written as the minimum starting point - any contractor who "builds to code" is simply building to the most unsafe they are legally allowed to.

[Marshall Brown]

Actually, codes are written as the minimum starting point - any contractor who "builds to code" is simply building to the most unsafe they are legally allowed to.

Agreed and I should have probably thrown a "help" before "avoid" in the first sentence.

I spent almost 20 years as a construction project engineer/manager and there was always some dispute between contractors and proponents/customers about what was "good 'nuf." Obviously the contractor never wanted to exceed applicable codes or contract requirements while the proponents wanted the best he could get.

In a large corporate situation the proponent organization wanted to look good to upper management by getting more than they paid for (or a lot of times they wanted to cover up the fact they didn't ask for the right thing and they wanted the contractor to pay for their mistake).

In my own home I try to "code plus" things but I have to admit that a contractor who does that with out funding from the prime contractor/owner will lose the bid or lose money on the job.

[Griffen]

So for the most part where I'm from, If there is an attached garage, and the attic space above the house is open and the attic space is open in the garage there is no need to even have a celing. This "fire rating" is not a requirement in single family homes where I'm from. As long as the adjacent living space has a barrier and drywall then you can say its fire rated, but more importantly it keeps out noxious fumes. I wouldn't worry about a attic hatch in a garage if its not heated. Having a ceiling in a garage IMHO creates a small space which means concentrated amounts of Carbon Monoxide. Just because you have your garage door open doesnt mean the exhaust will automatically leave the space. Exspecially in Winter when the exhaust is visible.

My home is set up in this exact same manner. I have Carbon Monoxide detectors in the home, and they have never gone off.