I was driving down the street and saw that large column of smoke. A working house fire. As I passed the Firehouse, the engine was just pulling out.
I pulled over and waited for it to pass. As I passed the subdivision entrance, I saw the rest of the trucks rushing towards the scene.
The next I heard about it was on the local news. Firefighters on scene of a house fire, fire was supposedly started by a car in the garage.
I was thinking of my past experiences with house fires and that a garage fire is a multiple combustible fire. (Think of all the chemicals in a garage!?)
The one thing that I have to realize is that I’m not in the Midwest anymore. As I was analyzing the fire on TV, I noticed something. The firefighters where not doing an interior attack. Why? As a Midwest Firefighter I was in the attack mode and going through all the scenarios and experiences I have had. Why weren’t these firefighters doing an interior attack?
Then I got it! The obvious answer was staring me in the face…..
It was the roof! That clay tile roof was the obstacle. First, there was no way to ventilate and second the weight of the clay tile roof itself.
So I went into research mood.
A clay tile roof has an average of 10 lbs. per square foot, compared to an average asphalt shingle roof of 4 psf. The weight of an asphalt shingle roof has a few things that comprise of the weight. The asphalt shingle itself, the nails, felt paper and the OBS or plywood sheeting.
That combination weights less the 4 psf.
A clay/tile roof is comprised of the some of the same items such as nails, felt paper and PBS/plywood with the addition of concrete, the tile itself and aluminum flashing for the valleys and peaks. All that can weight more the 10 psf.
So what does an average roof weight? I found the great link below that could calculate that. (I’m not a math guy) but this is the math (poundm/ft2)
So using this calculation a 2000 sf roof covered in asphalt shingles weights 4.7 (lbm/ft2) x 2000 = 9,400 pounds
And now the clay tile roof for a 2000 sf roof.
12.8 (lbm/ft2) x 2000 = 25,600 pounds
That’s a 16,200 pound difference! Now I know why the Firefighters didn’t go in for that interior attack! We all should know this, but through all my 20 plus years in the Fire Service, I didn’t have one class on this. NOT ONE!!
Lets all think before we act. (Knowledge, Training and Experience)
So, the next time you get called out for a house fire, look at that roof. That one look will save your life!!!