How To: Roofs for Do-it-Yourselfers, Option A
If your slope is 3:12 or higher, your best bet is an architectural shingle with a fiberglass mat. Sometimes called a laminated or dimensional shingle, these have not been around as long as the three-tab type. But they have become the most popular choice in America. That is mainly due to deeper shadow lines and better curb appeal.
But they also offer a significant benefit for both professional roofers and do-it-yourselfers. Architectural shingles don’t have a fussy vertical alignment to contend with like the three-tab variety. And they are typically larger in size, so installation is fast and simple.
How To: Roofs for Do-it-Yourselfers, Option B
Although shingles can be installed on roofs as low as 2:12, I’ve found that applications on slopes that low are problematic. The slightest dip in the roof can allow water under the shingles, eventually causing a leak. For that reason, I recommend “low-slope” roofing systems for any roof under 3:12.
Good low-slope roofing systems have been around a long time, but most are either very hazardous or require special equipment and techniques. Professional grade systems that are DIY-friendly are a relatively new addition to your roofing options. Your best bet is a three-ply self-adhering modified bitumen system.
The first ply is a nailable base sheet that allows for simple reroofing when the time comes. The mid-ply gives you backup protection that you don’t have with single-ply roofing systems. The cap sheet takes all the abuse that man and Mother Nature can dish out, while the watertight mid-ply remains protected underneath. And the roof goes on without the fire hazard of torches and the burn hazard of hot asphalt.