I'm thinking about finishing two walls in my garage with plywood under the sheetrock so that I can hang hooks and shelves and such where I want without searching for the studs. However, the plywood is lame for fire safety. Is there a good alternative material that will accomplish the same thing and be at least as good as sheetrock for fire performance?
Garage wall and fire
- Thread starter Ironcrow
- Start date
5wndwcpe
Well-known member
They do make fire-rated plywood. Probably a little spendy though. But the question begs, why the concern ? I mean the plywood is behind the gypsum, which is most likely attatched to wood studs anyway, so if the inside of the wall is burning, what's the difference between the plywood and the 2x4's.
boiler7904
Well-known member
If you're really concerned about an electrical fire, wood studs burn just as easily as regular plywood.
l_bilyk
Well-known member
Why would you worry about an electrical fire? Have everything installed to code and it shouldnt be an issue
I agree that electrical fires in code houses are super rare. As for the flamability of plywood etc. If there is a real fire in the wall you need to get out of the house and let the firemen do the work. The fire rating etc does not mean the fire will magically be put out and you won't have to call 911. Plywood will actually be better than just sheetrock because any additional item you have between you and the flames, in the wall or not, is a good thing. It buys the humans more time to get out and fight the fire. So in essence, it would help.
Geez guys! I know fires are rare. Yes, much of the wiring in my shop is run on the surface of the wall in metal conduit. All the wiring is of ample size, new, and installed to code or better. Still, I have NOT cancelled my fire insurance, turned my fire bottles into garden sculpture, and stopped paying the fire protection district fee...
I'm just thinking that it wouldn't be a good idea to fill a largely inflammable garage (concrete, masonry, and steel) with fuel.
I'm just thinking that it wouldn't be a good idea to fill a largely inflammable garage (concrete, masonry, and steel) with fuel.
6768rogues
Banned
There is fire retardant treated plywood, but it is pricey. There are intumescent paints that make plywood fire retardant, but they have to be reapplied every few years. I would wire it to code including the correct amperage breakers for the wire gauge, and forget about it.
Maybe I can get comfortable with plywood. I stopped by the local blacksmith shop/school and he had plywood walls in the forge room (more durable than sheetrock for students swing hot metal around he said). If he's not scared, I don't know what my problem is 
About 12 years ago I was charging the battery on my kids PowerWheels Jeep and the charger or battery short circuited and caught fire. The fire department responded pretty quick and was able to keep damage to the house at a minimum. The garage was added after I built my house and the wall between the two is comprised of 1/2" plywood sheathing and T-111 grooved plywood. The firemen said the double layers is the only thing that saved my house. IMO a plywood wall would be beneficial.
Virtually every fire resistant structure is based on:
Flammables > non-flammable > structure
You want to have:
Non-flammable > flammables > structure
- then drill numerous holes in the non-flammable surface. This seems eccentric. Why not fit plywood panelling over the sheetrock ? The likeliest cause of a fire is heating/cutting/welding, where you should be able to spot any surface fire and deal with it, whereas ply inside the wall introduces a (minimal) risk of a smouldering fire in the wall structure.
Steel pegboard over the sheetrock would be another, albeit spendy, possibility.
Inflammable means flammable ? What a country !
Flammables > non-flammable > structure
You want to have:
Non-flammable > flammables > structure
- then drill numerous holes in the non-flammable surface. This seems eccentric. Why not fit plywood panelling over the sheetrock ? The likeliest cause of a fire is heating/cutting/welding, where you should be able to spot any surface fire and deal with it, whereas ply inside the wall introduces a (minimal) risk of a smouldering fire in the wall structure.
Steel pegboard over the sheetrock would be another, albeit spendy, possibility.
Inflammable means flammable ? What a country !
6768rogues
Banned
I am probably picking nits, but plywood is combustible not flammable. Gasoline is flammable, diesel is combustible. Cool stuff.
On a popular restaurant concept that my firm does the architecture for, we spec 1/4" plywood underneath 1/2" gyp bd for all surfaces that decor is going to be hung on. Haven't had a single code violation using this route. Just a little more reasoning to go with the plywood and not worry so much. ;-)
PAToyota
Well-known member
Quite frankly, you're over-thinking things here. Yes, electrical fires do happen. Mostly from shoddy workmanship, wiring not up to code, or overloading circuits.
As for plywood inside a wall burning, the main thing is that you don't have an air supply in most cases. You are much more likely to have a fire outside the wall, which is why the gypsum board on the outside of a wood framed wall is the consideration. You're protecting the wood studs with the gypsum board from a fire that starts outside that wall.
As for the generic issue of plywood "going up like a match" - it actually takes some work to get it started. I routinely make jigs out of plywood and scraps of 2x for welding projects and they have some pretty good burn marks on them but I have never once had to actually put out a fire on one of them. Now, if you throw a scrap of plywood in a fire where the flames can get to the edges - that is a different matter. But it takes a fair amount of work to get it lit from the surface.
Um, you mean like the gasoline and plastics and fabrics in the vehicles and all the other stuff that you will likely store in the garage like paints and solvents and boxes of Christmas decorations and such?
Again, there is cause for concern to do things right and not create an unsafe condition, but I really think that you are over-thinking things.
As for plywood inside a wall burning, the main thing is that you don't have an air supply in most cases. You are much more likely to have a fire outside the wall, which is why the gypsum board on the outside of a wood framed wall is the consideration. You're protecting the wood studs with the gypsum board from a fire that starts outside that wall.
As for the generic issue of plywood "going up like a match" - it actually takes some work to get it started. I routinely make jigs out of plywood and scraps of 2x for welding projects and they have some pretty good burn marks on them but I have never once had to actually put out a fire on one of them. Now, if you throw a scrap of plywood in a fire where the flames can get to the edges - that is a different matter. But it takes a fair amount of work to get it lit from the surface.
I'm just thinking that it wouldn't be a good idea to fill a largely inflammable garage (concrete, masonry, and steel) with fuel.
Um, you mean like the gasoline and plastics and fabrics in the vehicles and all the other stuff that you will likely store in the garage like paints and solvents and boxes of Christmas decorations and such?
Again, there is cause for concern to do things right and not create an unsafe condition, but I really think that you are over-thinking things.
To further aggravate the situation - what does a person do about any electrical outlet boxes, etc., that might be cut into the wall between garage and house. Is there a method that does not violate code and/or good judgment???
Thanks, ju539
Thanks, ju539
russlaferrera
Well-known member
Plan "A" Use 1/2" sheetrock, cover with 3/8" plywood, cover with 1/4" sheetrock.
Plan "B" Use 5/8" sheetrock vertical position, skim coat, cover with 5/8" sheetrock in horizontal position. The skim coat will make the wall one piece.
Cut 3" circles 2" down from the top of the wall every 16". Install smoke detectors on the ceiling directly in front of the 3" holes. Should any fire start the smoke will travel up and out the 3" hole setting off the smoke alarm. The reason for all the holes is the source of the fire will be unknown. (Want to nip it in the bud.) All alarms must be wired together and to the home.
IMO You should consider the following. A flammable storage cabinet for all paint and combustibles. Have a full time service to monitor your home. (Things happen when you are not there) several fire extinguishers and an escape plan..
Plan "B" Use 5/8" sheetrock vertical position, skim coat, cover with 5/8" sheetrock in horizontal position. The skim coat will make the wall one piece.
Cut 3" circles 2" down from the top of the wall every 16". Install smoke detectors on the ceiling directly in front of the 3" holes. Should any fire start the smoke will travel up and out the 3" hole setting off the smoke alarm. The reason for all the holes is the source of the fire will be unknown. (Want to nip it in the bud.) All alarms must be wired together and to the home.
IMO You should consider the following. A flammable storage cabinet for all paint and combustibles. Have a full time service to monitor your home. (Things happen when you are not there) several fire extinguishers and an escape plan..