Eaves Gutter Minimum Fall

Rainhead overflow or specific box gutter overflow must be at least 30mm below the height of the back of the box gutter.

Eaves gutter minimum fall.

A flat roof will have a watertight surface with a fall of 1 in 60 or 1 in the case of lead. In normalised eaves gutter systems outlets downpipes and gutters are designed to create free discharge conditions meaning that only the gutter run needs to be calculated. You need to decide how far the rain has to travel and which type of gutter is to be fitted for example where you have a run over 10m you may need a shallow gutter with a steeper fall or a deeper gutter that can handle more water assuming the fascia is tall enough to take a deeper gutter. Place the line spirit level on the string.

The amount of collected water increases until it spills over the sides of the gutter. Gutters must be installed with a fall of not less than 1 500 for eaves gutters unless fixed to metal fascias and 1 100 for box gutters. The eaves gutter cross sectional area is calculated on the flow in the gutter. Downpipe eaves gutter long straight eaves gutters box gutter to rain water head box gutter vertical faces box gutter side o flow box gutter vertical o flow storm water pipe size storm water network overland flow path spitter upstream end custom rain water head.

The water drains into a gutter that is fed into a downpipe. The gutter slope also called the pitch is the amount the gutter tilts down to let rainwater flow out of it. This effectively states that all box gutters must allow for 30mm of freeboard which is from the overflow point eg. I fall or slope box gutters to be installed with a minimum uniform fall of 1 in 200 towards the outlet.

Therefore if a 90 diameter downpipe is sufficient and a 150 or greater diameter is used the gutter area will remain the same as the flow in the gutter will not change by using a. Eaves gutters must be supported by brackets securely fixed at stop ends and at no more than 1 2m centres. If gutters slope too severely they don t hold water and water could splash over the sides in heavy rain. If the length of the gutter is 10 5 metres 35 feet the amount of slope required is 1 25 cm 1 4 inch multiplied by 1 metres 3 5 feet which when rounded up is 2 5 cm 1 inch.

Using en 12056 3 which assumes free discharge conditions the following tables giving gutter flow capacity and the effective roof area able to be drained by a gutter run. If gutters don t slope water gathers in them. That is the total catchment flow divided by the actual number of downpipes used. Calculate the gutter slope by dividing the length of the gutter needed by 10.

A roof must be designed with a suitable fall to allow the rainwater to discharge.