General Question

LuckyGuy's avatar

Do California homes in fire zones use gypsum board / dry wall / sheet rock for their walls?

Asked by LuckyGuy (35622points) October 11th, 2017

It is common here to have sheet rock, dry wall, interior walls. I’ve tried burning the stuff and it is impossible. The material is considered fireproof and may be place near wood burning stoves and high temperature flues.
On the news I’ve seen pictures of homes destroyed in the recent wildfires. The homes are flattened with nothing left standing.
In such fire-prone areas why aren’t they built with “fire-proof” materials? Maybe they are and the wild fires are just too hot. But I don’t see tons of sheet rock on the piles. Is it not used there? Do any of the homes have water stored in the attic for fire prevention? Would that help?

Here is some info about dry wall testing.
“National Fire Protection Association 101 Code for Safety to Life from Fire in Buildings and Structures, a noncombustible material is defined as a material that, “in the form in which it is used and under the conditions anticipated, will not aid combustion or add appreciable heat to an ambient fire.” Materials are tested for noncombustibility in ASTM E 136 Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750 C. The test exposes small samples of the material to a stream of air heated to 750 C, (1382 F). The material is deemed noncombustible if:
1) Sample temperatures at no time exceed 780 C, (1436 F).
2) There is no flaming after 30 seconds. 3) Once the sample loses 50% of its weight, there is no flaming and sample temperatures never exceed 750 C, (1382 F).”

That is a strict test and different grades of dry wall are more resistant than others.

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25 Answers

Tropical_Willie's avatar

Fire-proof like cinder block walls and metal roofs. No wood or flammable material on the outside?

Tropical_Willie's avatar

Believe they use normal “Stick” construction and drywall.

LuckyGuy's avatar

I can understand if the outside layer is allowed to burn while leaving a solid core protection – like a heat shield on a space capsule.
We put aluminum (or plastic) siding over foam board insulation on the outside of the house. That tightens the house and reduces heating costs. Behind that are 2 layers of dry wall.
My roof is asphalt shingles with small stone grit that resists flame. They do burn at high temperatures though.
It just seems like the houses are made of matchsticks. Surely there is a fire code. I just don’t see it.

kritiper's avatar

Sheet rock has been the preferred method of constructing interior walls in homes and businesses since about 1950. Normally, it is not a suitable substance for outside wall construction.

MrGrimm888's avatar

You’re talking about 70 foot tall fires, moving at over 25 mph. Most of the worst affected areas have large amounts of very dry fauna, and high winds. The high winds both push the fire to spread faster, and provide more oxygen. The dry foliage burns at a high temperature.

Keep in mind that the World Trade Center towers were built with very strict codes. Fire just fucks shit up. The trailer park that recently went up was like a marshmallow on a stick. No chance.

Even if the structures were fire retardant, the oxygen would be taken out by the fire, and replaced with smoke. If the dwelling is engulfed in flames, there isn’t much that can be done for someone trapped inside. Hopefully, they suffocate before they burn. Scary stuff…

Kardamom's avatar

Yes, virtually all homes in CA have drywall walls, but the construction underneath is wood 2 by 4’s, wood construction before the drywall is added. Then there is usually plywood on the exterior walls before the stucco is put on. None of that seems to help much. Construction costs are already ridiculously high out here, having steel beams would make the cost impossible : (

We also have tile roofs in most new construction, at least after about 1990.

johnpowell's avatar

My apartment is 2X4 with drywall on the inside and OSB on the outside with some ply on the floor. Most of the places I lived in California were the same. Even if drywall could withstand the heat the fire would still destroy the bones of the house and the drywall would just collapse since it wouldn’t be attached to anything.

I think this is sane construction. Fires are not my concern, earthquakes are. My 2×4 and particleboard apartment will just sway in a earthquake. And even if it was to collapse I could probably survive it since the materials used to construct it are so light. There is no way I would live in a brick house here.

YARNLADY's avatar

Drywall is a sort of chalk that is held in the shape of 4×8 wall boards by using glue and paper. When the glue and paper burn, the chalk crumbles or, in the case of these extremely hot fires, it simply vanishes.(turns into tiny smoke particles).

LuckyGuy's avatar

Thanks for the info. I am glad to hear they use drywall and tile roofs in recent construction.
There are new grades of dry wall. I had heard of Type X Fire resistant dry wall but did not give it a thought until these fires. It has some limitations but it does seem like a good idea.
What if walls had an extra layer? Or have every other support be a metal stud instead of wood?
Would insurance companies be willing to share the cost?

Are any homes faced with bricks or stone?

Tropical_Willie's avatar

@LuckyGuy I had a friend that was a actuary for a large insurance company, I think they had an umbrella in the logo in the 1970’s and 1980’s. They don’t share costs, they limit the amount of money they pay out from premiums.

johnpowell's avatar

@LuckyGuy :: I think these catastrophes are so rare that we really shouldn’t go around changing building standards. We are looking at around 2K structures out of millions in California.

It is a tragedy but not a reason to run around enforcing stricter standards. Hopefully people will learn to clear the dead vegetation from their land.

That is kinda the crux of this. California had a really wet winter (remember the Orville dam). So shit grew. Then they had a really dry summer and as a result you got a lot of tinder. That is the stuff that is burning now.

LuckyGuy's avatar

@johnpowell Good points. It would be a good idea to clean out the tinder and downed trees.
If people burned it in a good wood burning stove they’d save energy too. 20 pounds of wood is the roughly the same BTU content as a gallon of heating oil and about the same carbon footprint.
OTOH maybe some people with wood burning stoves might set their houses on fire – defeating the purpose.

It just seems like there has to be a way to stop or at least slow down a string of house fires. 100 gallons of water stored in the attic connected to a 150 ft of garden hose, artillery shells loaded with fire retardant, wall board that foams and releases a retardant. Something. Anything.

LuckyGuy's avatar

What about this material Fire retardant impregnated plywood ?
From their brochure:
“MagTech consists of a 3 mil thick, non-combustible, fiber-reinforced
magnesium oxide (MgO) board laminated to untreated oriented
strand board (OSB) on one or two faces, as required by code and
building application. The non-combustible MgO board lamination
process assures a composite uniform section to reinforce the OSB
while also providing both flame and thermal resistance.

The noncombustible MgO laminate prevents
both flame and smoke penetration through the sheathing, as well
as enables the OSB to remain free of fire retardant chemicals for
greater strength of the overall composite sheathing system.
MagTech is free of hazardous chemicals, with no VOC (off-gas)
present during fabrication. The MgO panel face provides an attractive
tile-like surface that mitigates the spread of flame and heat with a
burn-through resistance that is greater than that of standard wood
structural panels that are treated with fire retardant chemicals.

chyna's avatar

@luckyguy Wouldn’t the water evaporate or get moldy?

filmfann's avatar

All of the above.
My house in San Leandro had lathe and plaster walls. My house in Concord was mostly drywall and spackle, mostly.

LuckyGuy's avatar

Here is another supplier of fire retardant plywood sheathing.

@chyna Maybe. The tank might need to be flushed every year – like when you clean your furnace. The tank and hose would be flexible so it would not crack if the water froze. During a fire the house would burn through.

funkdaddy's avatar

It doesn’t really matter what you make the house out of if everything in it and around it is flammable. The things that we fill our houses with burn easily and the natural elements we surround them with burn easily.

Put another way, how much more would you pay for a house with walls that burn 10% slower? If you have a house fire, they’re still going to be torn down and replaced and you’re still going to lose everything inside to either fire or water damage.

Tropical_Willie's avatar

The temperatures of wildfire approaches or exceeds 1500 * F.
The 20 to 70 MPH wind dry and flash fire ignite almost everything. While living in Southern California in the 1950’s I remember a friend’s father having to replace all the nylon window screens at their vacation property in the Santa Monica mountains. The flash fire went through at an estimated 90 MPH but didn’t catch all properties on fire. Not all the neighbors were a lucky.

LuckyGuy's avatar

It might make difference in a neighborhood like this one: before and after photos .
Most of the trees are still standing but the houses are gone.

Wouldn’t it be worth a try on a few houses in a neighborhood? The increased cost would be minimal during the construction phase. (based upon the pricing info I could find I estimate about $5 more per foot around the perimeter – call it $1500.)

LuckyGuy's avatar

By the way… see that small, fried, smudge in the lower left hand corner of the after picture? That would be me clutching a garden hose.

zenvelo's avatar

A colleague was just showing me pictures of his brother’s place in Santa Rosa that was completely destroyed, including the restored ‘66 Mustang that is now nothing but scrap metal.

The fire was so intense that aluminum rims on cars melted into a stream of slag.

LuckyGuy's avatar

I spoke with a retired Director of operations of a fire department and he gave me more insight.

Under ordinary conditions the homes in the neighborhood are already fire-resistant. If one home catches fire the neighboring homes will survive. This fire is different. The flaming debris and high winds from the wild fire basically torched all the houses almost at once and there were not enough resources to put them all out.
if the the houses are fire resistant how do the fires start? In much of the homes the flames begin around the windows.and rain gutters. People add window treatments like shutters or decorative trims that are not of resistant material. Some homes have plastic or composite rain gutters which collected leaves and then started burning when the wildfire flaming debris landed in them.
What should the people do to save their homes? With winds and conditions like these – , Nothing! Get out! You.would first be overcome by smoke then the intense heat would get you. Your small amount of water would be insignificant. Pack some stuff and get out!

Case closed.

Any advice? Watch your window treatments, Clean your rain metal gutters,

johnpowell's avatar

@LuckyGuy When I was about 4 years old my parents started building this house.

I suggest zooming out a bunch to note the vegetation around. This was in a little valley that got pretty windy. It was during the summer and fires tore through there. We learned the house was in danger and being stupid my parents drove in to rescue the TV and unimportant shit with the two kids in the backseat.

As we were driving to the house you could see little fires become bigger fires and little fires appearing out of nowhere. It spreads at a amazing pace.

And the situation in Cali is 100 times worse. These fires are so fast moving they are literally a fast hurricanes made of flames.

funkdaddy's avatar

@LuckyGuy – Tons of house fire videos on YouTube, but these made me think of you

IBHS Research Center Ember Storm Test Highlights – Insurance Institute for Business and Home Safety doing tests on model homes with what appears to be their own custom “ember generator”...

They have lots of others. If we’re going for a strictly clinical engineering look at the problem, I don’t know if it gets much better than these guys.

LuckyGuy's avatar

@funkdaddy That is a fantastic demonstration! Frightening! I can see that a guy with a hose is useless.

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