How to Determine the Best Roofing Angle for a House

Articles | Roofing
May 6, 2022

Roofing angles are one of the trickiest elements in the design of any building. Many factors play a role in what angle, or pitch, a roof will have. A roof must be strong and sturdy, both structurally and in terms of weather resistance. It also has to be steep enough to allow water to run off it easily. But if a roof is too steep, it takes up more square footage and will have significantly higher materials costs. Of course, there are aesthetic considerations too. The angle of a roof helps determine the overall look of a house.

So how exactly do architects determine the best roofing angle for a house?

How Roofing Angles Are Measured

Angle, steepness, and pitch are words usually used interchangeably in the roofing business. Each essentially refers to the roof’s vertical rise over horizontal run: the ratio of how many inches the roof rises for every 12 inches of depth. For example, a roof with a pitch of 3:12 would rise 3 inches for every 12 inches of horizontal run toward the peak of the home.

If you’re curious, or if you have a project that requires it, you can determine the pitch of your own roof. A tape measure, a bubble level, and a pencil should be enough to get the job done. Just head into the attic and place one end of the level against a rafter. Check the bubble to make sure the level is, well, level. Next, make a mark on the level exactly 12 inches from the point where it’s touching the rafter, then use the tape measure to measure the distance from that 12-inch mark on the level to the underside of the roof. You’ll then have the numbers you need. The rise (the vertical distance from the level to the roof) over the run (12 inches) is the roof’s pitch, or angle.

Why Do Rooftops Need To Be At an Angle, Anyway?

The primary reason rooftops must be angled is obvious: they need to allow water to roll off them. Water is one of the most powerful solvents in the world. You need only to look at the vast canyons and deep valleys carved out by water to understand that, over time, water will eat its way through everything. Even the most well-made roof is no match for the relentless onslaught of rain, snow, or ice. If puddles are allowed to sit on top of a roof and don’t have a way to drain, the roof will inevitably develop leaks. If water leaks into a home through a compromised roof, it will cause even more damage, which may result in the need for tens of thousands of dollars’ worth of repairs.

Of course, not all roofs are at an extreme angle. Some might seem to be completely flat, but in reality, very few roofs are totally flat. The rise should be at least ¼ inch and could be as high as 2:12. Even the seemingly flat rooftops of apartment buildings are constructed to have a slight angle and built-in scuppers to drain away pooled water. This allows these roofs to drain properly, even when they lack the more dramatic pitch of a traditional house.

Roofing angles exist for more than just the drainage of water. A steeper roof also helps protect the home from heavy winds by distributing the pressure of the wind during inclement weather.

How Do You Know What Angle Is Best for Your Roof?

We’ve established that weather is the single most important factor in determining why a roof has the pitch it does. But how do you actually go about figuring out what the angle should be? The first step is to consider the climate where you live. You’ll notice that many houses look dramatically different depending on where they’re located. New England is famous for its steep, gabled rooftops, designed especially for the region’s frequent wind, rain, and snow. By contrast, homes in Arizona, where rainfall is rare, are typically much flatter.

Of course, weather shouldn’t be the only factor that determines the angle of a rooftop. It’s also a matter of personal preference. Steeply angled roofs are considered aesthetically pleasing, and if you want a home that has one, it doesn’t really matter if you live in an area where rainfall is scarce. Just remember that a roof should be constructed to resist the elements in your area.

Keeping Your Roof in the Best Shape Possible

A roof is built to withstand heavy wind, rain, and of course, the sun’s ultraviolet radiation. A well-made and well-maintained roof can last for decades; although eventually, all roofs need to be replaced. Roof replacement is a huge, expensive job that requires a great deal of time, effort, and materials. You can, however, stave it off as long as possible with proper maintenance.

A steeply angled roof is built to resist heavy winds, but you could still lose a few shingles if a gale sweeps through your neighborhood. Replacing those shingles quickly is of critical importance, as bare spots on the roof are weaknesses where water can easily seep through.

It’s a good idea to have a professional roofer inspect your roof at least once a year and make any necessary repairs. It’s even better if that roofer has emergency services available. If your roof starts leaking, you won’t want to wait to have repairs done. You’ll know who to call and that the repairs will be made promptly. For the best roofers in the business, contact Interstate Roofing in the Portland and Vancouver area for all of your roofing maintenance and repair needs.