How to adjust the gutter pitch to prevent water from pooling?

Question

Hi all, I’m dealing with stagnant water in my gutters, they seem to be pitching in the wrong direction (away from the downpipe). Could someone break down in simple terms:

* How much slope a gutter actually needs
* How to calculate the proper pitch
* How to adjust the slope to fix it?

Any advice or tips would be greatly appreciated!

R4addZ · Answer

Hi @foxhound

One thing I would be looking at is the support clips. You will notice in the picture that there are only 2 and the nearer one is less angled than the first. It is possible that the clips are missing and so the weight of water has dropped the outside edge of the gutter which seems to be the case by the way the water is pooling towards the outer edge. If you can't immediately see a solution, I would call a roof plumber.

MitchellMc · Answer

Hi @foxhound,

As a general guide, a fall of around 1:500 to 1:1000 is commonly used, which works out to approximately 10-20mm over a 10m length of gutter. The exact fall can vary depending on the gutter profile and the manufacturer's installation requirements, so it's always worth checking their recommendations.

The simplest way to check the existing pitch is to stretch a string line from one end of the gutter to the other or use a laser level. Measure from the string to the gutter at several points and you'll quickly see whether the gutter is sloping away from the downpipe or if there are any low spots where water is collecting.

If the fall needs correcting, the usual approach is to adjust the height of the gutter brackets. You will likely need to remove the guttering entirely from the brackets to access the fixings that secure the brackets. Depending on the type of brackets installed, this may involve removing and repositioning them to establish a consistent fall towards the outlet. Once adjusted, it's worth testing the gutter with a hose to confirm water flows freely to the downpipe without pooling.

Please be aware that gutter installation and adjustment may be considered regulated plumbing work in your state or territory. All regulated plumbing work, including modifications to guttering where applicable, should be carried out by a licensed plumber. If you're unsure whether the work is regulated in your area, it's best to check with your local authority before proceeding.

Please let me know if you have any questions.

Mitchell