Roof Rainwater Drainage Calculations

Standing water in your basement driveway or yard.

Roof rainwater drainage calculations.

Wondering how much rainwater you could collect off your roof. This article describes several methods for determining the drainage capacity required to safely drain water off of building roofs whether from rainfall melting snow or a combination of those water sources. 512 490 0932 501 w powell ln 206 austin tx 78753 harvesting rain conserving water and managing stormwater in texas since 2004. Simplified suitable for flattish roofs with little or no vertical faces or steep roofs draining to one side of box gutter only or any roof if you are in a hurry and make the necessary allowances for all catchments.

The roof drain calculator below is based on the maximum amount of rainfall in inches per hour of the hypothetical worst storm in the past 100 years and which has a two percent chance of occurring in any given year. We describe online roof drainage requirements calculators pertinent plumbing standards a table approach to looking up roof drainage. Calculate drains needed. The above sizing data is offered as a guide only.

The result is the number of drains needed. Upon completion a full set of rainwater drainage design calculations are provided confirming the suitability of products. Use this rainwater harvesting calculator to find the answer. Rain barrels store and reuse rainwater helping to reduce the overtaxing of sewer systems and protect the quality of groundwater.

Box gutter with rain water head at end of box gutter. Take the roof s total square footage and divide by the total square footage handled by one drain. Three spreadsheet for free download with direct links. The new nds app is the perfect tool for determining runoff and system requirements on the go.

Nds quickly identifies drainage problems and selects the right solution to resolve issues at home. The speed at which the rain collects at the drain. Download free calculation excel sheet for the design of drainage systems for roof rainwater and storm water these calculation spreadsheets calculate the quantity of rainwater and the sizing of gutter rainwater. Mep work provides free excel calculator for drainage calculation of roof rainwater and storm water.

A simple rain catchment system can provide water for outdoor use resulting in. The roof drainage outlets and rainwater downpipes are calculated based on the design principles for gravity drainage systems established in ss525 2006 code of practice for drainage of roofs. Calculate your drainage install on site. The calculations below are meant for drainage from flat roofs where water are expected to spread over the entire flat roof during rain.

How to calculate roof runoff. Roof drainage requirements specifications.