In last month’s column (“Truckie on a Hot Peaked Roof ,” March), I addressed peaked-roof structures that truckies commonly encounter while running around atop a fire building. Understanding these roof structures is a good start, but it doesn’t quite crack the surface of the subject (pun intended). After all, it’s one thing to know what you’re standing on, and another thing to know how to open it for ventilation.
Roof Materials
I don’t have enough room here to tackle every type of material we may encounter when opening a peaked roof, so let’s review the most common materials we can expect to find under normal conditions.
Homes built in the early 1900s are commonly sheathed with lumber known to carpenters as “one-bys,” meaning each board is 1 inch thick by X inches wide (usually 4—12 inches). In older construction, a 1 by 6 would refer to a board with a thickness of 1 inch and a width of 6 inches. However, current one-by lumber starts as 1 inch thick and is milled to ¾ of an inch thick. So that same 1 by 6 would really be ¾ of an inch thick by 5 ¾ inches wide–but still referred to as a 1 by 6.
The boards are horizontally attached to rafters that are usually between 16 and 24 inches apart. The rafters may be milled boards that are 2 inches thick by at least 4 inches wide. A 4-inch-wide board would usually be found in a truss. Stick-built homes normally utilize boards with a width larger than 4 inches for rafters.
The size and spacing of roof rafters were not always defined for older construction; therefore, you can find many different configurations. Nowadays, there are codes to follow and the size and spacing of roof rafters are based on a predetermined span chart. Visit the American Wood Council Web site to download a document that shows examples of these charts (www.awc.org/pdf/STJR_2005.pdf).
One-bys were typically installed in two different ways: 1) open sheathing or skip sheathing–placing the boards next to each other with a small space between the boards; or 2) closed sheathing–placing the boards next to each other with no space between them. Wooden cedar shake shingles were then applied on top of the sheathing. The spaces between the one-by boards allowed for air circulation to prevent cedar shakes from rotting.
Many of these roofs are still around; however, most have been re-roofed with asphalt shingles. Some have had the cedar shakes removed and have been re-sheathed with plywood and/or oriented strand boards (OSB) that are nailed to the one-by pieces. Many other roofs have been re-sheathed with plywood and/or OSB nailed to the cedar shake shingles.
At some point during the mid-1900s, tongue-and-groove pine, usually 1 by 6s, started appearing on roofs. This is a system of closed sheathing where each groove fits onto the tongue of the piece below it. Asphalt shingles are commonly found on top of tongue-and-groove boards. Cedar shakes usually require spaces between the sheathing; however, some codes don’t allow skip sheathing in which case tongue-and-groove boards may have been be used.
In the early 1900s, the Portland Manufacturing Company began manufacturing plywood in the United States, and by the 1960s, plywood on roof surfaces was common. Plywood is made by shaving logs into thin veneer sheets and gluing them together at right angles. Plywood comes in 4′ by 8′ pieces and should be installed horizontally with staggered vertical seams. The size of this sheathing matches up nicely with our modern practice of spacing rafters every 16 or 24 inches. The sheets come in varying thicknesses and grades; the minimum thickness for residential roofing is 3â„8 of an inch thick. Although I’ve been on roofs with thinner sheathing, I don’t believe they were in compliance with building codes.
As previously noted, OSB stands for oriented strand board. This material is manufactured by gluing together small pieces of rectangular-shaped strands of wood. It comes in the same 4′ by 8′ sizes as plywood and is installed in the same way. By 2000, the use of OSB for roof sheathing had become very popular due to the lower price compared to plywood sheathing.
Installation
After the sheathing is applied, roofing materials are added on top. There are many different types of roof coverings: slate, metal, porcelain and tile, not to mention a composite of any of these materials or even other materials manufactured to look like these materials. That said, the majority of residential peaked roofs found across our country are asphalt.
I live in the Northeast and that’s what we usually encounter here. I’ve also spent considerable time in the Midwest and found lots of asphalt there. I’ve participated in several live burns near Sacramento, Calif., and the bulk of the buildings we trained on had asphalt shingles. Finally, a firefighter from Plano, Texas, recently visited my fire department and, like most normal conversations I have with people, I asked him what material he usually finds atop a standard roof in his area. His reply: asphalt.
So unless you live and/or work in an area where something other than asphalt shingles is the norm, you could probably assume your vertical ventilation activities will involve one of the aforementioned sheathing methods. Of course, there will be exceptions. I’ve opened several slate roofs, a tile roof and a metal roof, but the asphalt roofs I’ve opened number in the hundreds. Because of this, I plan out my truck crew’s work accordingly. When we encounter something other than asphalt, we just have to adjust as best as we can.
Roof-Opening Tools
The tools we need to pierce a roof’s surface are basic and the assortment is easily manageable by a truck crew. As noted, the most common types of roofs are those with pine boards tongue-and-groove plywood and OSB underneath asphalt shingles. Keep in mind that you may also encounter roofs covered with a mosaic-like arrangement of different materials under the shingles–the product of remodeling additions and general roof repairs. The good thing about this: We need the same tools to open all these roof types.
The truckie’s staple tool is the pick (aka pick axe). A flathead axe is also OK. Axes can become problematic when the roof is sheathed with plywood, especially nice fresh plywood. It’s rare that axes alone can cut through a plywood-sheathed roof and create the correct-sized hole in a timely manner. Further, the axe in plywood is extremely straining on the choppers.
A splitting maul has always been a favorite tool of mine for ventilation. Whenever I find myself in a group of firefighters discussing roof ventilation, I ask if anyone has ever opened a roof using a splitting maul; the most common answer is no. The splitting maul is used to smash a hole through a roof–not cut one.
I remember being a kid and jumping up and down on frozen puddles or small ponds trying to create a hole in the ice. The first couple jumps would produce nothing more than some creaking noises. Then a crack would appear and you could poke through the surface. You’d then move outward from the original hole stomping with one foot until you had made a good sized opening–or your foot slipped in the hole.
This procedure is similar to that for opening the roof with the splitting maul. You start pounding and when you believe you’re hitting an area that isn’t over a rafter, you keep swinging until the round tip of the maul pokes through the roof’s surface. At this point you just keep pounding away, increasing the size of the hole until you’ve opened it enough. When you’re done the hole likely won’t resemble a 4-by-4 square, but rather a circle. If you don’t have a splitting maul, a sledgehammer will also work but you won’t have the blade on one side for slicing. I don’t want to push my beliefs on others–unless their helmet reads “Buffalo Truck 14”–so I’ll just suggest giving the splitting maul a try sometime; I guarantee that you’ll be pleasantly surprised.
The chainsaw is my favored device for opening any of the roofs discussed here. You need a chainsaw that’s well maintained and ready to go and it must be equipped with a fire service ventilation chain. Using the chainsaw or even a rotary saw with the appropriate blade makes the venting process much faster than using simple hand tools. Power saws will work equally well on all the asphalt roofs we may encounter.
Traditionalists may not want to admit that a power tool can outperform them, but the goal is to get the roof opened quickly and safely and power tools can greatly help firefighters accomplish this. You’ll be hard-pressed to find any construction site where handsaws haven’t been supplemented with or totally replaced by power saws.
Conclusion
So there you have it–a simple guide to the materials atop residential peaked roofs and the basic tools you’ll need to open them. Of course, there are more materials used for roof sheathing than I’ve covered here and there are certainly many more roof coverings than asphalt shingles; however, for most of us climbing to the roof, what I’ve covered here is the norm rather than the exception. Preparing to handle the exception is prudent, but failing to be prepared for the norm is foolish.
