Shared stud wall with house?

[jage]

I've removed everything to the studs on 3 sides of the garage in preparation for insulation and drywall.

The fourth wall, shared with the walk out basement, turns out to be normal studs with drywall on each side. The house siding doesn't continue and there is no firewall or anything, just common fiberglass insulation between sheetrock panels.

First question is, how common is this?

Second, it doesn't seem safe fire being the most obvious reason...is it even legal?

Last, when I tear out the garage side drywall and reinsulate from the garage side, what comes next to make it safe/proper leaving me back at garage side studs?

 

[Kevin54]

5/8"' fire rated drywall is usually required. This will have to go all the way to the peak.

Will it stop a fire? Probably not, but it will slow a fire down if you have a fire start in the garage.

BTW....welcome to Garage Journal. Always nice to see new members showing up. Be sure to post up some pics of what you're working on. We like pics!!!!

 

[theoldwizard1]

Double 1/2" drywall is better. Stagger the seams. You would be surprised how long that will hold a fire back !

 

[crepr12]

just curious what state are you in and who built your house?...Good luck with the fix action

 

[Tim The Tool Man]

The drywall you ripped off in your garage was your firewall. 5/8 drywall which is tapped and mudded is an approved firewall. The goal of a fire wall isn't to necessarily stop/prevent the spread of fire, it is to delay the spread of fire long enough for you and your family to be able to exit the building.

It wasn't too many years ago when 1/2" drywall was accepted as a fire wall, and not to many years before that Masonite was acceptable, and before that, nothing was all that was needed...

 

[the gypsy]

I would start with roxul insulation instead of fibreglass pink, then I would invest in Durock or Permabase. The Roxul is fireproof, waterproof and soundproof insulation which will slow the spread of fire, you can see a demonstration on you tube. The durock or permabase is a cementatious base type board. Although it is more expensive I think it is superior to drywall. This is my personal choice and a very good solution. IMHO.

 

[the gypsy]

Oops I'm sorry I forgot to add that the Durock or Permabase is for the shared wall only the other walls can be a thicker drywall (FIRE RATED). The Roxul insulation would be installed all around. I would like to add that you should see with your State building code for the specifics.

 

[cantoo]

The drywall was likely legal when the house was built. The building code does change you know. Check your local current Building Code for todays approved system. Ask them about gas proofing too. If you redrywall then your next weak link will be the door frame, is it wood? Most door frames are wood, very seldom is steel used in resi.

 

[rlitman]

Double 1/2" drywall is better. Stagger the seams. You would be surprised how long that will hold a fire back !

Maybe, maybe not.

The problem with regular sheetrock in a fire, is that it crumbles and collapses.
Fire rated type-X sheetrock has fiberglass fibers mixed in with the plaster inside. That keeps it up after it is dehydrated by the heat of a fire, and that is very important. More so, than the total thickness.

 

[Tim The Tool Man]

I would start with roxul insulation instead of fibreglass pink, then I would invest in Durock or Permabase. The Roxul is fireproof, waterproof and soundproof insulation which will slow the spread of fire, you can see a demonstration on you tube. The durock or permabase is a cementatious base type board. Although it is more expensive I think it is superior to drywall. This is my personal choice and a very good solution. IMHO.

Durock is not an approved material to use as a fire stop. Intuitively it would seem like a superior product compared to sheetrock but to my knowlege there has been not testing or certifications that would make it a product that I would recommend.

Gypsum is actually a natural fire retardant and the paper is impregnated with retardant as well. 5/8 sheetrock also has been tested and approved as a fire block...

 

[CNGsaves]

Before you close everything up with insulation and sheetrock, make sure you've planned out all your electrical needs for outlets, compressor 220v, welder 220v, high outlet (switched) for hanging garage heater, lighting in ceiling, etc.

Also while you're planning ahead, what about internet, CATV, telephone, intercom, etc. from the house.

Finally, running natural gas from house with black pipe steel would be easy while all the walls are still bare studs (ie for hanging garage heater).

Good luck and post up pictures to get best replies.

 

[rlitman]

Durock is not an approved material to use as a fire stop. Intuitively it would seem like a superior product compared to sheetrock but to my knowlege there has been not testing or certifications that would make it a product that I would recommend.

Gypsum is actually a natural fire retardant and the paper is impregnated with retardant as well. 5/8 sheetrock also has been tested and approved as a fire block...

It isn't just about it not being certified. It is that it is not as good at rejecting heat.

Gypsum board will not only stand up to the heat of a fire and act as an insulating surface (for this though, you need type X with the glass fiber reinforcement to not crumble and collapse), but it also has another interesting property.

If you've ever mixed plaster, you would know that it cures by incorporating the water you mix into it, into the material. When exposed to the heat of a fire, the water inside is driven off in the form of steam. This is actually quite a lot of water, and it takes time for the fire to "boil" off that 5/8" thick layer of water before it penetrates to the opposite side. In the meantime, the water prevents the far side of the board from getting above around 300F.

With cement board, while the board may indeed stand up to fire, it lacks this property, and the heat passing through it will ignite the studs behind it in short order.

 

[kbs2244]

If you check your codes you will see they will call drywall either acoustical or fire proofing.
It doesn’t have any legal decorative use.
If your garage ceiling isn’t dry walled then the shared wall should be dry walled to the roof for fire retarding.
One layer of 5/8 is good enough for most residential codes, but I have seen 2 and even 3 required for multi-family or commercial.

 

[pmiranda]

Yep, know your local codes and beyond that, think safety beyond what the bare minimum is... I know our first house had a cheap hollow core door between the garage and utility room. That would've burned through in about 5 minutes! When we redid the kitchen we got a nice steel entry door that was actually fire rated and it made me feel better. Probably should have put in drywall in the attic to the roofline, too, but I didn't know any better at the time. Not that the cedar shake roof wouldn't have burned right over it anyway

 

[Tim The Tool Man]

It isn't just about it not being certified. It is that it is not as good at rejecting heat.

Gypsum board will not only stand up to the heat of a fire and act as an insulating surface (for this though, you need type X with the glass fiber reinforcement to not crumble and collapse), but it also has another interesting property.

If you've ever mixed plaster, you would know that it cures by incorporating the water you mix into it, into the material. When exposed to the heat of a fire, the water inside is driven off in the form of steam. This is actually quite a lot of water, and it takes time for the fire to "boil" off that 5/8" thick layer of water before it penetrates to the opposite side. In the meantime, the water prevents the far side of the board from getting above around 300F.

With cement board, while the board may indeed stand up to fire, it lacks this property, and the heat passing through it will ignite the studs behind it in short order.

Yes I realize that gypsum contains a significant amount of water and that is what makes it a great fire retardant. Just an FYI all 5/8 drywall is fire rated (at least in my area/State) and all dimensions of drywall contain that glass fiber you mentioned, it is actually a reinforcement and I don't really think it does much for the fire rating as glass will melt at a pretty low temp.

Also, I did say I would NOT recommend Durock.