Flat Porch Roof Pitch Standards

Low pitched roofs are generally difficult to maintain and you need special materials to prevent leaks.

Flat porch roof pitch standards.

Sunday august 5 2018 the traditional metal roof types such as 5v crimp shown above and corrugated are rated by the manufacturers for use down to a 3 12 pitch three inches of vertical rise for every foot of horizontal run. On a ladder tall enough to reach the end of your roof put the level against the house parallel to the ground where the roof meets the house. If you have a flat roof shed or porch you ll need to be sure it has adequate pitch or you could find yourself having to conduct frequent roof repairs due to poor drainage. This is the number needed for the pitch calculation.

Measure 12 inches from the bottom of the level and mark the spot on your house. The most commonly used roof pitches fall in a range between 4 12 and 9 12. However you can only use this pitch with built up roofing or specialized synthetic roofing. Anything less than one eighth of an inch may pool on the roof.

The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. Porch roofs come in different forms and styles thus taking the shape of the roof. Flat roofs which aren t perfectly flat require a small slope to allow for water runoff. This is suited for large buildings and houses wherein this would make them appear more attractive and also works in maximizing the space.

Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs. Various styles of a pitched roof can be built or you can purchase pre manufactured trusses. The same self healing characteristic restricts the use of coal tar pitch to roof systems of little or no slope typically 1 8 of an inch per foot or less. Then measure from the spot created vertically to the roof.

Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled. The flat roof already has a slight pitch as it is required by law. Generally such roofs have a pitch ranging from 1 2 12 to 2 12. Some building codes start at a quarter of an inch per foot.

Pitches above 9 12 are very highly angled and are designated steep slope roofs. You will need to ensure that you are in standards with your local building codes and have the permits required.