How Do You Pitch A Flat Roof

Rafter rise run from the pythagorean theorem.

How do you pitch a flat roof. However flat roofs require much more aggressive and consistent maintenance than a pitched roof. Some will choose to keep their pre existing flat roof on their structure underneath the new pitched roof to save removal costs but others might not be able to consider that option. Roof pitch refers to the slope which the rafter creates. Depending on the climate your flat roof will only last between 15 and 30 years if well maintained.

You will need to ensure that you are in standards with your local building codes and have the permits required. How to calculate roof pitch. Pitch tan angle where angle is the roof pitch expressed in degrees. The flat roof already has a slight pitch as it is required by law.

Determine the roof span and pitch. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. The way pitch also known as roof slope is measured is rise over run. To get the minimum pitch for a metal roof the vertical rise per foot is divided by the horizontal slope.

You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof. A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible. Tear off the old materials and apply roof sheathing. Rise run pitch where pitch is expressed in percent.

So if your roof rises 4 inches for every 12 inches of horizontal length then the pitch of your roof is expressed as 4 12. If you used long lasting materials on your pitched roof you could expect it to last much longer. Flat roofs also don t last as long. Install the new material.

Various styles of a pitched roof can be built or you can purchase pre manufactured trusses. Minimum pitch for metal roof the minimum roof slope for metal roofs is dependent upon the roof profile. The process for converting a flat roof into a pitched roof depends on your individual structure and your individual needs there is no one size fits all option.