The Roof Over Your Head
Can you imagine a home without a roof? It's not exactly a pleasant prospect, which is why it is essential that the roof over your head is well structured and maintained. For even the most basic of shelters, a roof is the primary component. The architectural design considers not only aesthetic appeal, but also such factors as climate of the area in which the home will be situated, the cost, and the material most suitable.
Roofs can be either sloped , with a pitch of over 2.5 inches, or flat. Flat roofs are far cheaper to construct, as they require less building material and labour. However, they are generally reserved for homes constructed in areas of low precipitation and milder climates, as well as for commercial structures and larger buildings. The reason for this is that not only does it lack aerodynamic properties, but its flatness inhibits snow and rain from running off. Despite flashing and the layer of waterproof membrane on the roof, leaks eventually result from weighty and damaging accumulation, even with the proper placement of gutters. Therefore, flat roofs tend to require yearly time consuming and costly maintenance . (If you'd like to direct runoff water to the gutters of your flat roof, you can create valleys on its surface with panels which forge a path to gutters and downspouts.)
Houses constructed in areas of higher precipitation and harsher climates normally have pitched roofs of varying degrees. In areas where there is high precipitation, particularly snow, the degree of the slope increases greatly so that snow can easily slide off the roof. For rain, it is easily directed to the gutters. The slope, or the “run” is measured by the horizontal length and the degree at which it rises. For example, roofs that are considered “low slope” are under 5/12, meaning every 12 inches of horizontal length, it rises 5 degrees. The higher the pitch, the more expensive as labour and building materials accrue. And because it is common to attach gutters to every part of the edge of the roof, the size of the gutters and properly placed downspouts should increase to accommodate all runoff water flowing off the roof faster from gravitational pull. Gutters should be a minimum of 5-7 inches in width, with every 40 feet of horizontal run sloped at a minimum of 1-2 inches. This will prevent runoff from pooling in the gutters and flow easily to any downspout placed ideally at every 25-45 feet of gutter length. Downspouts should be a minimum of 7 square inches, but should increase in size depending on the amount of rainfall in the area and the size of the roof. Typically, a six inch downspout will handle 1200 gallons of runoff water.
The most popular sloped roofs in North America fall into two main categories: gable and hip.
Gable roofs are constructed so that only two sides of the roof are sloped at a degree higher than 2.5 inches to form a peak in the shape of a triangle. Both snow and rain can easily run off to the gutters on this type of structure. They require far less maintenance than a flat design but are almost as easy to build. One drawback, however, is that damage can still result from harsh winds hitting the end walls at either end of the roof. As a result, make sure your endwalls are properly braced with metal or wooden vertical/lateral bracings.
Some specific types of gable roofs are mansard (also known as “French”), cross gable, and saltbox. A saltbox roof is where the slopes are asymmetrical, having a longer slant on one side.
A Hip roof is constructed so that all four sides of the roof are sloped to form the peak. Pyramid and cross hipped roofs fall into this category. This is the most aerodynamic because each side of the roof is sloped with no end walls.
Some other types of roofs that are less popular in North America are gambrel and shed.
Whatever the style of roof, consider the placement of your gutters or eavetroughs and downspouts so that runoff water can easily be drained from your home.