Roof Pitch For Rain

A roof is part of the building envelope.

Roof pitch for rain.

The high steeply pitched gabled roofs of northern europe are typical in regions of heavy snowfall. A roof protects a house and porch from snow and rain as well as the heat of the sun. The chief reason for having a roof pitch is to redirect water and snow away from the roof and avoid any percolation that might result from stagnation of water on the roof. You can measure pitch with a 2 foot level and a tape measure.

A 5 inch gap for instance is a 5. Flat roofs are common with industrial buildings boasting wide roof spans and are also popular in dry climates for houses where there is no need for the roof to help disperse rain and snow. Minimum roof pitch for a covered porch. If water does not properly run off of a roof it will begin to seep in causing rot interior damage and possibly dangerous black mold.

The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches. This will extend the life of your roof. Adding a covered porch adds exterior space to a house and providing a. An example for a steep sloped roof is 8 12.

If you are building a new roof however consider the climate to determine the correct pitch and proper materials. As standard practice places with heavy rainfall or snow storms will have higher roof pitches compared to places that experience less rain and snow. The purpose of pitching a roof is to enable water and snow to run off so the greater the amount of rain and or snow an area receives the greater the amount of pitch needed for the roof. Looking at the diagram a roof from a to d also intersects the same amount of rain as the main roof.

The steep roof of the tropical papua new guinea longhouse for example sweeps almost to the ground. Thus pitch is typically greater in areas of high rain or snowfall. Even in these arid regions so called flat roofs are still installed with a slight pitch to keep water from pooling on top of the structure. To put it in perspective.

But what is really interesting it doesn t matter what the roof does to get from point a to point d. The safest way to determine the pitch of an existing roof is to measure from inside your attic using a level tape measure and pencil. The characteristics of a roof are dependent upon the purpose of the building that it covers the available roofing. The steeper a roof s pitch the more windblown rain it can collect.

In fact any roof between rainfall lines b and c will intersect the same amount of rain and therefore have the same catchment area.