Shingles are a tried and true roofing system for steep-slope buildings throughout the world. They are durable, easy to install, and affordable. All of that said, there are places where they are not the best option. They are doing more harm to your building than they are helping!
The roof pitch is the number of inches the roof drops (vertical) compared to the number of inches runs (horizontal). Meaning that for a roof with a 7/12 pitch the roof drops seven inches for every twelve inches it runs. This measurement is extremely important in determining the type of roofing system you will be installing. This is something your roofing contractor will determine during your inspection.
Shingles are a steep slope roofing system. Most people do not know this but shingles are not the primary waterproofing material on your roof. They are a shell to protect what’s underneath. As a result, they are considered a product that helps “shed water”. Because of this, they are no goof for areas where water will be pooling before it drains. The minimum pitch where shingles can be installed is a 2/12 pitch, but Big Time Roofing does not install shingles below a 4/12 pitch. When installing shingles below a 4/12 there are extra precautions you have to take to make sure it is watertight. These include additional layers of underlayment and ice and water shield.
You can find contractors that will ignore building codes and manufacturer installation instructions. Installing shingles on a low slope will be cheaper and very quick. But the consequences are significant. You will not have a roofing system that is accepted by the manufacturer and therefore you will not be able to get a warranty. Secondly, you will likely be replacing the system in 1-5 years because it will start leaking and cause damage to what’s underneath.