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Vertical ventilation: Proposing a new way to cut a big hole

This simple method for a quick cut on a pitched roof allows for fewer cuts and safer operations

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Let’s face it, we need a no-nonsense method of cutting a hole – bigger, faster and safer – when operating on pitched roofs.

Photo/Chris DelBello

I frequently see video footage of fire scenes, and many times, truck crews with permanently assigned officers going to the roof without any observable plan for performing vertical ventilation. It is obvious in their actions – and even more obvious in their inactions. They fail to lead while on the roof, and they simply point to a general location and garble some orders to their firefighters. More often than not, this leads to poor performance, too small of a vent hole, or abandoning the operation entirely. They find themselves in this position because they fail to train regularly, and they fail to train their firefighters to complete understanding of the assigned task.

Also, if you pay any attention to social media, you will see 100 different ways to perform vertical ventilation. In one video, a firefighter appears to be trying out for a position as a Ginsu chef, essentially flinging the saw around and marking all the rafters with quick bumps of the saw and then cutting and lifting the saw out multiple times in an effort to avoid cutting the rafters.

Here’s a fact: If your saw is not on or in the decking, you are not cutting. If you are not cutting, you are not making progress. If you are not making progress, you are not improving the interior conditions. If you are not improving the interior conditions, you are not helping the victim or the attack crew. And if you are not helping the victim or the attack crew, then what are you doing?

Let’s face it, we need a no-nonsense method of cutting a hole – bigger, faster and safer – when operating on pitched roofs.

A proven method

Here’s one proven method that meets those needs for a pitched roof:

  • Step 1: After deciding the location to cut, place the saw blade on top of the ridge. We are not trying to cut through the ridge board, only the decking. Once the saw blade sinks into the decking, pull the saw blade straight down for 6 feet.
  • Step 2: Move over 12 inches and put the saw blade on the ridge board again and pull straight down for 6 feet.

Even if you do not use the method discussed in this article, the presence of a ridge vent should clue you in that a top and bottom cut is not necessary, especially with today’s construction methods. As you can see in these photos, when a ridge vent is installed, the builder cuts the decking 1 inch from the ridge board to allow for natural ventilation in the attic space.

Photo/Chris DelBello

Repeat this motion for a total of six vertical cuts from the ridge board 6 feet straight down. In doing so, you end up with a 36-square-foot hole vs. the standard 4x4 hole that only yields a 16-square-foot hole.

There won’t be any top or bottom cuts. How can this be?

Let’s consider the construction methods and materials in pitched roofs. The standard decking on your typical residential pitched roof is only 7/16 of an inch thick. When built with plywood/OSB decking, the top piece of decking is typically cut-to-fit. So, if you cut the total 6-foot vertical cut from the ridge, you will not only cut entirely through the top piece of decking, you will have cut very near through the next row of decking as well, making the piece you just cut so weak that it is easily broken and pulled back onto the roof or pushed in.

These six vertical cuts must be kept to 12 inches. This will ensure that we avoid any possibility that we end up with any decking attached to two separate rafters, requiring the clean-out person to put in additional effort in removing any decking that doesn’t fall in.


A single sheet of OSB decking is 4x8 feet. When a builder starts the roof decking, they begin at the bottom of the roof rafters near the eves or overhang and work left to right. As they finish the first row, they move up to the next row and work in a left to right direction until that row is complete. They continue laying full sheets until they reach the top row nearest the ridge board. Once they reach the top row of decking, they will cut the top row to fit. This could be any dimension but is typically about 2x8. So cutting 6 feet down will get you through the top piece of decking and the full sheet of decking below that, making this method quick and easy.

Photos/Chris DelBello

This method also works very well with tongue-and-groove decking.

Before you hate on this method, try it. You will see for yourself that it is not only faster, but it is also safer, especially if you are dealing with poor visibility or a sketchy roof.

In using this method, you are not walking around your cuts. You are constantly walking away from your cuts, away from the fire, away from the weakest part of the roof and back toward your ladder.


With modern construction, builders are using cheaper material and less material to throw houses up faster yet make a bigger profit. In looking at some houses under construction in one territory, I discovered that when one builder was installing the decking, they used a total of four nails to secure the decking to the rafters. They also used six clips to secure the decking to the adjoining pieces of decking together. Get out and see what is being built in your area.

Photo/Chris DelBello

Why it works

Here are some additional details of why this method works:

Rafters: In using this method and not cutting the top or bottom cuts, as long as you keep your cuts straight, you essentially remove rafters from the equation.

Ridge vents: When I see videos of vertical ventilation being performed on a pitched roof with a ridge vent and visible smoke is pumping out of said ridge vent under pressure, I always laugh a little to myself. It’s not really funny, but over and over, it shows that firefighters do not take the time to truly size-up the roof before making that initial cut and simply start cutting because that is what they were taught to do. If they understood the significance of a ridge vent, they would know that the top cut is entirely unnecessary, as it is not even attached to the ridge board.

When a ridge vent is put on a pitched roof, the decking is cut away 1 inch on both sides of the ridge board. That means the decking is not even attached to the ridge board. Why take the extra time and effort to make the top cut at all?

Heavy smoke: This method is especially safe and effective when humidity is high and winds are low. Oftentimes, when we get on a roof, it is almost like we are inside the structure, as the smoke banks down and reduces our visibility. In using this method, again, you remove the concerns of cutting across the rafters and walking around your cuts. This method also removes the need to cross any cuts when you cannot see the decking at all.

Sketchy roofs: I am not one to advocate for dangerous operations. However, if you intend to place a crew under a roof so they can operate under backdraft-type conditions, then vertical ventilation is called for. If the roof seems sketchy, perhaps weakness caused by age or rot, use a roof ladder. For that matter, use two.

In using two roof ladders, you provide for a much larger and stable work area for the firefighter cutting the hole. When the cuts get closer to the ladder, simply move the ladder closest to the cuts out of the way and continue to cut until the six vertical cuts are made.


Begin by placing the saw bar over the ridge. Do not cut through the ridge board, only the decking. Cut straight down for 6 feet. Once the first 6-foot cut is complete, return the saw bar to the ridge, move over 12 inches and cut straight down 6 feet again. Repeat this action for a total of six separate six foot cuts that are no more than 12 inches apart. This yields you a 36-square-foot hole using the same number of cuts as you would find in your typical text book hole that results in only a 16 square foot hole. Because your cuts are so long, it makes the clean out easy, even if the cuts did not completely go through both pieces of decking. This method works good on tongue and groove decking as well.

Photos/Ezequiel Ramirez

Before anyone blows a gasket, remember that there is not a single documented case of a firefighter working from a roof ladder and falling through the roof due to roof failure.

Also remember, we use the roof ladder for two reasons – to work on steeply pitched roofs and to spread the load. Spreading the load applies to sketchy roofs, too – the same sketchy roof you are putting attack crews under. Think about that for a minute. Read it again.

Give it a try

In closing, I want to remind you of the reasons to use or at least try this method:

  • It is the same number of cuts as a traditional hole.
  • It is faster.
  • It is safer.
  • It is a bigger ventilation hole.
  • It removes the concerns of the rafters being cut.
  • It is easier on the clean-out man.
  • It is also easier to train your crew to use this method versus all the other methods currently in use around the country today.

Find a roof and try it! Get out and train – and be safe!

Chris DelBello is a 31-year veteran of the fire service. He currently holds the rank of senior captain with the Houston Fire Department, working in the Midtown District. He is also the district training officer, which encompasses all the stations in downtown and midtown, and holds a Training Officer II certification. DelBello also serves as a captain with the Fort Bend County (Texas) Emergency Service District. Connect with DelBello via email.