Roofers have been cutting flat tar roofs into sections for years, but before that they used an axe. That process was labor intensive because tar roofs are essentially one piece of material without an entry point for a prying tool. To remove a flat tar roof, it must be divided into sections so it can be removed and ultimately disposed of. That was a lot of work with an axe. Eventually, large motorized roof cutters were developed which made the job much easier.
The same idea is true for multi-layered shingle roofs. Shingle roofing that is cut into manageable sections is much easier to remove and dispose of. We just had to figure out how to cut asphalt shingles efficiently. Our first test was a three-layer shingle tear-off with ridge caps that had been left on for each roof install and shingles that overlapped over the peak. That was a lot of shingles! To start we cut right down the middle of the ridge caps (after adjusting the blade depth). Aside from the thickness of all the shingles, this is probably the most effective of all the cuts because there are no roof nails down the middle of the peak and it serves as an entry point for the tear off tool. Next, we did for that same roof was to cut down the roof from the peak to the gutter line in a series of vertical strips. One other critical consideration to keep in mind is blade depth. The way we did that was by making a narrow horizontal test cut about six inches long.
Start the process by slowly dropping the blade into the roof until you start to see a little saw dust (just scuff the boards with the blade). Once you have determined your depth you can start cutting the vertical lines from the peak to the gutter line. What we discovered on that first multi-layer tear-off was that cutting up the roof made the tear-off a lot easier. Plus it was much easier to haul the debris to the dumpster. We no longer had to unravel a bunch of shingles to carry them to the dumpster (in the case of a walk-able roof). Also, we found that by cutting shingles into manageable sections it was easier to keep the debris out of the landscaping.
Over the course of time we realized that adding in horizontal cuts made for even easier tear off and clean up, especially for two-story homes. The way this worked was by cutting sixteen inch by sixteen inch squares that could be directly tossed into the dumpster, even from the second story, instead of double handling the material by throwing unmanageable piles to the first level and then into the dumpster.
Keep the Shingles Together
One of the key benefits removing a roof that is cut into sections is keeping the sections of shingles together when tearing off. There are two factors involved in doing that. A very important factor is technique. This involves more finesse than force. By prying the nails out as you go, the squares tear off quicker and cleaner.
The best way to cut asphalt shingles
The second involves shingle tear-off tools and demolition saw blades. Tear-off tools with a wide base (such as a shingle eater) help hold the shingles together better. The type of saw blade is very important when cutting up a roof. There were no such blades on the market, so we developed our own circular saw blade for cutting asphalt shingles. BigBlue is the best saw blade for cutting asphalt shingles.
BigBlue 5T and BigBlue 3T blades can cut through shingles and nails without clogging, warping, or cracking. They are extremely durable as they will cut for a mile or longer. There is no other 7 1/4″ blade with massive carbide teeth and a wide kerf with huge gullets (open space in between the carbide teeth) available.
We also developed the RipCart, which is a standup saw-cart for cutting up sloped and flat roofs. This tool alleviates the need to crawl with a circular saw and is easier on the circular saw and blade. In this application the blade and the saw are suspended over the roof and are less apt to bind. When tearing off an overwhelming and difficult multi-layer roof the temptation is to plow into the job without consideration. A little thought and planning can save a lot of time and energy, so it’s worth it to be organized and to have the right tools.