How to Repair Plastic Guttering

Thank you for visiting my page about gutter repairs. My name is Daniel and I have worked in the roofing and guttering industry for over 16 years. I hope this page will be useful for you.

I have created several pages on this website that you may be interested in; see step-by-step instructions on how to replace guttering on a house. See how much it typically costs to replace guttering or perhaps see my guide to replacing the entire roofline – fascias soffits and guttering!

There are dozens of reasons why a plastic gutter may suddenly start leaking and require a repair, a solution that works in one situation may not work for everyone. There are however some steps you can take to determine what is actually causing the problem, it is then just a case of applying the appropriate solution.

Rather than just guessing what the cause is, I recommend the following steps as outlined on this page. When a professional roofing or guttering company checks over a faulty gutter this is the type of checklist they will go through before attempting a repair.

Please note that this is applicable for the repairing of plastic gutters although similar checks can be made on any type of gutter, such as cast iron.


The Problem With Roof Moss

I have stated this on other several pages within my website, but I feel it is worth mentioning it again: the #1 cause of expensive gutter and pipe blockages is caused by roof moss being washed by rainwater into the guttering. Here is my guide to removing roof moss without using pressure/power washing equipment.

Here you can see a list of tried and trusted moss killing chemicals that will prevent the moss from growing back and causing you issues with your new guttering. If your guttering is suffering from frequent blockages or is overflowing then I suggest you read these pages right now.

I really cannot emphasize this enough – if you have moss on your roof then chances are you will suffer from:

  • Overflowing gutters
  • Blocked drains
  • Reduced gutter flowrate
  • Rotten roofline boards


Gutter Blockages

If your property suffers from a blocked gutter, rain water pipe or even a drain the water can back up and either over flow the gutter or start leaking at a weak spot in the gutter system – usually a joint or outlet.

Solution – Unblock the gutter and rain water pipe, pour a significant amount of water in the gutter (with a hose perhaps?) and see what happens.

Check for Signs of Poor Workmanship

After you have cleared the gutters and pipe of any leaves, roof moss or other blockages and poured some water into the system it is usually very easy to see exactly where the leak is coming from. If a support bracket has come loose then re-secure it with a screw, the same applies to any outlets, joints or corner sections that have become dislodged.

All rainwater that collects in the gutter should flow towards the outlet and pipe, if the water doesn’t flow correctly and “ponds” in the gutter then it may overflow during periods of heavy rain. In this case the gutter should be re fitted with the correct alignment, making sure any rain water flows towards the pipe that have already checked for blockages.

Replace Joints and Parts

guttering to roofline

See more images like this in the photo gallery


Plastic guttering does suffer from thermal expansion and will sometimes slip out of the joints, in this case it is best to replace the part rather than trying to seal any gaps with mastic sealant as this is a questionable method to repair guttering with expandable gutter joints. If you have plastic guttering then you can buy individual replacement parts, they are easy to install as you only need a screw and screwdriver.

Occasionally when installing a new gutter joint the existing gutter length needs to be adjusted so it fits snugly into the joint. Very rarely does a whole new length of gutter need to be purchased.



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