Floplast Gutter Flow Rates

Whilst the look and feel of a gutter system is an important factor in choosing your new gutters, you should also give some consideration to the technical details, particularly on new-build installations. The flow rate of each gutter system varies with the size and shape of the profile. A square gutter system for example has a higher flow rate than its half round equivalent due to the steeper side walls. The information and gutter flow chart below will give you a better understanding of the different variations that are available.

Factors that Affect Flow Rates

In addition to design factors, flow rates for guttering vary according to the way in which they are installed. Gutters that are installed to a fall for example have a greater flow rate than those which are fixed level. Also the position of the running outlet (the connection to the rainwater downpipe) has a large bearing on the flow rate - downpipes that are in the centre of a run of guttering will always improve the flow rate when compared with downpipes fixed at the end of the run.

Size of Rainwater Downpipes

Somewhat surprisingly, the size of the downpipe is not a factor that affects the gutter flow rate, provided you use the correct recommended downpipe for the system in question. A downpipe is generally designed to have 10 times the capacity of the guttering to which it is connected. It is however important to keep downpipes free-flowing - we recommend installing an OG1 Balloon Guard in the neck of each running outlet to stop leaves and twigs from being washed into the pipe.

Maximum Effective Roof Area

If your roof is large and you want to check that a particular gutter system has the capacity to deal with the rainwater run off, click here to visit our page on choosing large gutters. On this page you will be shown how to calculate the area of your roof along with a capacity chart detailing the maximum effective roof area for each type of system.

Comparing Floplast Gutter Flow Rates

The gutter flow rate chart below compares the specific flow rates for each Floplast gutter system. The numbers on the left hand side of the table show the flow rates when the gutter is fixed level (no fall), and the figures on the right detail the flow rate when the gutter is fixed to a fall of 1 in 350. The top table shows the statistics for the outlet at the end of the gutter run whilst the bottom table shows the statistics for the when the outlet is installed in the centre of the gutter run.

You can click on any part of the charts below to download a copy in PDF Format.