Cutting asphalt shingle roofs before tearing them off started with flat tar roofs. That was the way that it was done was with an axe. That process was a lot of work but it had to be done because tar roofs were essentially one piece of material that had no entry point for a prying tool. To tear-off a roof, it must first be divided into sections in a way that it could be removed and ultimately disposed of. Over time, large motorized roof cutters were developed which made the job a lot easier.
Divide & Conquer
The idea of divide and conquer holds true for multi-layered shingle roofs also. The way we started cutting up roofs began with a three-layer shingle tear-off. This roof had ridge caps which had been left on during each roof install along with shingles which had been overlapped over the peak, instead of being cut back. If you do the math that’s a lot of layers of shingles. The first step we took in solving that problem is the same first step we take today when cutting up a roof for a tear-off. 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. The next thing 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 walkable 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 also discovered that making combined 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 considerations for tearing off cut up roofing 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.
Get the Right Tools
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. We discovered that there were no such blades specifically designed for cutting up roofs with a circular saw, so we designed our own.
BigBlue 5T and BigBlue 3T blades can cut through shingles, nails, tar and gravel without gumming up and can go over a mile in length of cutting. The keys to our blades not gumming up are the wide gullets between each carbide tooth and the size of the carbide tooth itself.
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.