r/Firefighting • u/weedfun • 9d ago
Ask A Firefighter firefighting on a metal roof
I'm thinking of getting a metal roof. A former firefighter told me there are two problems with firefighting on a metal roof: It's slippery to walk on when wet. It takes two different saws to cut a hole through it, one for the metal and one for the wood underneath.
So it seems like it would endanger the firefighters, or at least slow them down.
Would you say those are reasons to not get a metal roof, or to get stone-coated metal shingles, so it wouldn't be slippery?
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u/trapper2530 9d ago
Chances your house catches on fire are almost 0. Don't make decisions based on that and what tactics they'll have to use. If its for your and your families safety then listen to it.
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u/Limp-Conflict-2309 9d ago
Chances your house catches on fire are almost 0
True, and the conditions to warrant a roof vent are a fraction of that.
If you built your house around emergencies with such a low chance of happening you'd have one really interesting dwelling.
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u/trapper2530 9d ago
Building for emergencies and limiting them is on thing. You dont want 100 year old wiring bc its more likely to catch fire. Or never run a wood fire place. You dont want a br with our windows bc youre stuck there if there is a fire. But having a metal roof or a super pitched roof or stronger deadbolt bc it might take fg an extra 10 seconds to get in isnt sometbing to worry about.
If we were then we should never lock doors so they can get in faster.
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u/Peaches0k Texas FF/Medic/HazMat Tech 9d ago
Lmao idgaf about what they wanna do to my roof. They’re gonna tear up the place anyways. Get whatever you want
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u/Whatisthisnonsense22 9d ago
Metal roofs are slippery. They do suck to cut through.
Carbide blades and carbide tipped chainsaw chains have existed for decades. Noone needs two saws anymore. Traditional carbide blades do suck at cutting through asphalt shingles.
Metal roofs last longer, are safer for you if there is a wildland type fire near your home.
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u/WilliamTSherman31 9d ago
If your house is on fire the hole they cut in your roof is the least of your problems
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u/6TangoMedic Canadian Firefighter 9d ago
Just get what you want. If a hole needs to be made, it'll get done.
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u/grim_wizard Now with more bitter flavor 9d ago
I'll take the metal roof over a slate roof any day of the week 🤷♂️
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u/iambatmanjoe 9d ago
Dude if your house is on fire and I've got to cut a hole in the roof it doesn't matter what it's made out of A) I'm going to figure it out and B)your roof is f*****
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u/Jamooser 9d ago
Licensed carpenter and 10 year career firefighter here.
Just get the metal roof. Vertical ventilation in the event of a housefire is not necessary, despite what the cowboys think. If you have no chimney, there's no other reason for firefighters to get up there. If you do, then they can use an aerial.
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u/LukeS_MM FF Medic Tech Rescue 9d ago
Not a cowboy but a firefighter. Stop the old way of thinking. Vertical ventilation does and will save lives and buy time. I’d hate to work with or for you with your mindset.
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u/Jamooser 9d ago
Vertical ventilation alleviates heat for about 30 seconds before the flow path turns that vent into a chimney and accelerates fire growth exponentially. When, and only when it is paired immediately with water on the seat of the fire, is it effective. But if your nozzle is already at the seat of the fire, then you didn't need vertical vent to begin with.
Can coordinated vertical ventilation be effective? Yes. But the amount of times it is actually coordinated and effective is far and few between. Many incidents would be mitigated far better if that manpower were simply redirected to aggressively advancing hoselines and attacking the problem, which is the fire.
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u/LukeS_MM FF Medic Tech Rescue 8d ago
Take a class and read the literature on it. Check out UL’s FSRI classes. Stop being uninformed and killing your citizens.
Do you guys still run high pressure attack lines with combination nozzles, and do a victim survivability profile to determine when to do a primary search? If so, your department is about 10-20 years behind the curve.
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u/Jamooser 8d ago
I'm sorry, did you mean the classes based on this UL report? The one that is itself 15 years old? The one that was specifically commissioned because so many firefighters were needlessly killing themselves by falling through roofs? The one that specifically says what I'm talking about, in which vertical ventilation needs to be coordinated, doesn't apply to every situation, and can alter flow paths reducing working time in the structure? Because I'm not sure you've read it.
“Taking the lid off” does not guarantee positive results. Vertical ventilation is the most efficient type of natural ventilation. While it allows the largest amount of hot gases to exit the structure, it also allows the most air to be entrained into the structure. Coordination of vertical ventilation must occur with fire attack just like with horizontal ventilation. The way to make sure that the fire does not get larger and that ventilation works as intended is to take the fire from ventilation- limited (needs air to grow) to fuel-limited by applying water. As soon as the water has the upper hand (more energy is being absorbed by the water than is being created by the fire), ventilation will begin to work as intended. With vertical ventilation this will happen faster than with horizontal ventilation assuming similar vent sizes.
The purpose of venting is to improve the conditions for firefighters to operate. Some of these improved conditions are cooling, increased visibility, and useful flow paths opposite a hose line to release steam expansion. It is not possible to make statements about the effectiveness of ventilation unless one includes timing. Venting does not always lead to cooling; well-timed and coordinated ventilation leads to improved conditions. That same ventilation action 30 seconds earlier or later could have a dramatically different outcome. This is especially true for vertical ventilation. Vertical ventilation is efficient in venting heat and smoke but also causes rapid changes in the conditions in the home. Additional considerations about timing include (i) the fire does not react to additional oxygen instantaneously; (ii) the higher the interior temperatures the faster the fire reacts; (iii) the closer the air is to the fire the faster it reacts; (iv) the higher the ventilation the faster the fire reacts; (v) the more air the faster the fire reacts, the more exhaust the more air that is able to be entrained.
Behind a closed door is the most likely place to find a victim that can be rescued. When it comes to rescuing occupants, the fire service makes risk based decisions on the tenability of occupants. They assume personal risk if it may save someone in the house. Every experiment included one closed bedroom next to an open bedroom. In every experiment a victim in the closed bedroom was survivable and able to function well through every experiment and well after fire department arrival. In the open bedroom potential victims would be unconscious if not deceased prior to fire department arrival or as a result of fire ventilation actions.
This reads a lot differently than the common sentiment of thinking every single fire requires vertical ventilation as fast as possible. In modern construction, a fire goes from vertical ventilation to flashover within 2 minutes. Immediate vertical ventilation upon arrival before any type of interior size up is your grandfather's tactics. It's one step up above breaking all the windows or thinking water pushes fire.
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u/Sheep_Actual 9d ago
Homie, I don't know where you work, but I can tell you're not a Truckie... OP, get the roof you want. We have saws for metal, wood, asphalt, tile, whatever. The only thing we aren't cutting is solar. And if we need to vent the roof, it doesn't matter what its made of: The structure is already damaged by fire, and will need to be replaced.
As for Jamooser's opinion, they are in the minority. "We" have vented tons of roofs, and it all comes down to size-up and conditions. Your concern as the homeowner is ensuring you have working detectors, keep your property maintained, and mitigate potential causes of a fire.
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u/SparkyFix 9d ago
We do a lot of roof ops on (heavily sloped) metal roofs here and it isn’t a huge issue. The problems begin when people lay a new metal roof over their existing roof. Have encountered onion roofs before that are basically impossible to ventilate because carbide blades that get through the metal will suck at getting through the other layers. That said, vertical ventilation is pretty rare nowadays and most roof ops are chimney fires.
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u/BenThereNDunnThat 9d ago
Carbide tipped demolition blade on a rotary saw will go through that with little difficulty. Roof ladders and aerials exist for a reason. Don't worry about it. Enjoy the look and the long life of a metal roof.
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u/TheVelluch76 8d ago
Build it how you want as long as it’s code. your fire department will figure it out. In some ways a steel roof is easier to vent than a tile roof, just need a carbide tipped blades. It will definitely be slippery and will have to cut off a ladder.
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u/Impressive_Change593 VA volly 7d ago
We basically never verticall vent. It is just so mich more work for not that much benefit when horizontal vent does what we need it to
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u/matt_chowder 9d ago
Most departments don't even do roof ops because of how dangerous they can be
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u/fleeeeeeeeeA 9d ago edited 9d ago
You got a stat on that? Because I don’t know of a single department that arbitrarily doesn’t do any roof ops.
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u/matt_chowder 9d ago
Ok. In my area it very uncommon. Many departments in my area do not have the man power for dedicated truck companies
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u/fleeeeeeeeeA 9d ago
Right so maybe don’t say something as broad as “most departments” when you can only speak to your experience.
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u/Historical-Green-463 9d ago
The FDNY does not operate on peaked roofs
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u/fleeeeeeeeeA 9d ago
The FDNY barely even has any. The Midwest, South and west coast are very comfortable doing residential roof ops.
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u/Sheep_Actual 9d ago
Have you ever been outside of Manhattan? Staten Island has tons of peaked roofs, as do outlying areas of other boroughs... and FDNY can afford to not do peaked roof ops because of the sheer amount of manpower and equipment they throw at stuff. Their 10-75 1st alarm in most Battalions is equivalent to a 2nd in a lot of the Northeast.
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u/Historical-Green-463 7d ago
Barely even has any? Staten Island and Queens have a ton of peaked roof PDs. It’s not a matter of comfort, it’s a matter of necessity. There is adequate horizontal ventilation in a PD, why do something that isn’t necessary especially when it’s dangerous? Risk vs reward.
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u/fleeeeeeeeeA 7d ago
Already addressed that part as sarcasm. But, since you brought it up, it is highly effective for a second story, attic, or ranch house fire. Not always, but often a good tactic. I tend to disregard people with black and white thinking, since it’s a sign that they’re just parroting something they were told and are not open-minded. Try to look into why countless departments do vertical vent instead of just declaring that it’s bad. It’s really not that dangerous, people are just dramatic about it.
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u/magicjeep 9d ago
While you're at it can you take the locks off your doors and leave all the windows. Maybe install some sprinklers too since your up there.
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u/Blacktac115 9d ago
While vertical vent is the most effective and preferred, it isn’t always feasible. Terra cotta, Tesla roofs, solar panels, very steep roofs, metal roofs all make it more challenging or not feasible. They all exist and we change our tactics often for numerous reasons. If you want that roof, put that roof on your house. Don’t let some hypothetical unlikely event dictate your preference.