Roof Drainage System Plan

Of course the best designed flat roof has the correct amount of pitch to drain the water off naturally.

Roof drainage system plan. The value of tcdepends upon the size and layout of the roof and the drainage system. Functioning drainage system for steep slope roofs is to maintain a minimum roof slope. In the case of a building with gutters tcwill usually be the sum of the time taken for water to flow down the roof and the time taken for it to flow along the gutter to an outlet. Typically a steep slope roof slope is equal to or greater than 3 inches of rise per 12 inches of run 25.

Your building and location can help determine which drain will fit your roof needs. Developing the design criteria for a roof drainage plan that will perform with the roofing system to drain the roof is critical priorto the bid process and roof system installation. The design of the different drainage layers allows for a portion of the stormwater to be retained above where the water is allowed to flow freely off of the roof. The most critical of these issues is the flat roof drainage systems.

Secondary or emergency roof drainage is required wherever the buildup of water is detrimental to the roof structure. Ipc provides four steps to size the roof drains on a building. Deck balcony and railing connections should be designed and constructed to shed or drain water to the exterior. The drainage plane and drainage logic should encompass the entire building enclosure.

Establishing a minimum slope is critical because most steep slope roofing as. Screw a drain cover over the end of the tubing as it approaches daylight to keep critters out. Green roof solutions offers many different drainage layer options depending on system goals regarding water retention. Inner drains are resistant to freezing but can require careful maintenance to prevent problems.

Roof wall connections and roof dormer connections should be designed and constructed to shed or drain water to the exterior photograph 8. Secondary drainage shall be provided through the use of sidewall scuppers or internal roof drains. The main benefit of inner drains is that the system is hidden from view. To prevent erosion make a rock bed around the end of the tube.

Design assistance services are offered as a courtesy to the roofing design professional and contractors to ensure the project s success. Along with the benefits of a flat roof come unique challenges. Where the tube passes by the downspout from the gutter we installed a y fitting and drained the roof water from the gutter system directly into the main drainage line. The most critical role of the drainage layer is to provide an adequate flow of water off the roof during and after rainfall.