How to fit Plastic Guttering (an installers guide)

Welcome to Daniel’s Roof – Thank you for visiting my page about correctly installing Upvc plastic gutters!

The advice on this page compliments my page about gutter repairs and also my tips on roof moss removal (prevents gutter blockages).

My name is Daniel and I have been working in the roofing and guttering industry for over 16 years. If you want a hassle free gutter installation, I suggest you follow the tips on this page and also read my advice on gutter leaf guards and meshes that can prevent costly gutter blockages!

Did you know that the #1 cause of gutter blockages is actually roof moss rather than leaves? Check out this page about how to remove roof moss and here is a page about how to prevent the moss from growing back.

If you are fitting plastic Upvc guttering to your home then you need to get it right first time. Gutters that are fixed incorrectly typically overflow with water causing potential damp problems to fascia and soffit boards or wooden sils etc. This can happen all the time, only when it rains heavily, or only when the gutter is partially blocked with debris, either way it’s bad news and avoidable.


A Successful Gutter Installation

The key to a successful installation is to ensure that the rainwater flows in the correct direction. No guttering should ever be installed “flat”. They must be fitted slightly higher at one end, this ensures that the water flows to the pipe where it can then discharge into the ground.

It is also important to ensure that the guttering support clips are spaced no greater than 800mm apart as plastic guttering is quite flimsy and we don’t want it to sag. This can happen when the gutter is full with water or when there are icicles hanging from the front of the gutter.

The guttering itself is never screwed directly to the fascia boards, instead the support brackets are fixed to the fascia and the gutter is then simply clipped into place. This is because gutter suffers from “thermal expansion and contraction” in other words; it moves around alot, especially when in direct sunlight! The support brackets allow the guttering to slide back and forth without coming loose.


Ensure Rainwater Can Flow to Outlets

Ensuring that the brackets are fitted correctly is very important, get it right and the rainwater will flow in the right direction towards the outlet and downpipe, get it wrong and the gutter will overflow, especially during heavy rain.

Don’t forget that a gutter which holds water (called “ponding”) will have a substantially shorter life expectancy than a gutter that allows all water to flow to the outlet freely. This is because the rubber seals (gaskets) in the joints and parts will rot and degrade much quicker.

Take a good look at the large photo below, it shows a guttering system and new fascia and soffit boards being installed to a typical semi-detached property in England.

Guttering being installed to house roof

See more photos in the photo gallery

7 Steps to Installing Guttering

  1. Find the lowest point of the guttering, that is usually where the gutter discharges into a pipe.
  2. Find the highest point(s) of the gutter run, that is the furthest point away from the rain water pipe(s)
  3. Screw a support bracket to the highest point, this is usually 10mm below the roof tile
  4. Using a pencil mark out where each support should be located. The space between each should be approx. 800mm or less
  5. Now fix a bracket approx 200mm to the side of the rain water pipe, this bracket must be lower than the highest bracket you already fixed*, this is to ensure that all rain water flows out of the gutter
  6. Now tie a length of string between each bracket and pull it tight, make sure it doesn’t sag
  7. You should now have a perfectly straight line from the highest point of the guttering to the lowest point. You should now fix the remainder of the gutter clips using this string line as a guide (see photo above)

Once you have installed a few clips, you can place a spirit level between them to ensure all water will flow towards the pipe.

*the correct gradient fall for guttering will depend on the capacity of the guttering you have chosen and the number of outlets/pipes on the property. Guttering should never be installed perfectly flat/horizontal as it will collect water. Pay close attention to the position of the support brackets you are installing, use a spirit level and string line to double check that the gutter will flow in the correct direction.

Installing Fascia and Soffits with new Guttering

I often replace the roofline fascia and soffits along with the guttering, it rarely makes sense to refit old guttering to a new roofline. Here you can see my step-by-step guide to installing new roofline fascia and soffit boards (includes photos)

Just to Recap:

Have a good look at the photo I posted on this page and note the following:

Support brackets are no greater than 800mm apart (prevents potential gutter sag in later life.)

Extra care should be taken to ensure the brackets at either end of the length are in the correct place, before the string-line is set up

String line used to ensure there is no sag and gutter will flow in correct direction.

Always water test after installing gutter, it doesn’t take long to fit guttering so there is no excuse for allowing water to “pond”.



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    […] your guttering sags don’t try and repair it. You can replace it, including the downpipes, for under a hundred pounds. Is it worth trying to make the old stuff look […]