How to repair leaking gutter joints

It’s important to occasionally check your gutters when it’s raining to see if there are any problems. Rainwater dripping through gutters can cause damage and damp to your home.


Metal gutters

A metal gutter is difficult to take apart if the nuts and bolts have corroded. So try to seal the leak by scraping the joint clean, drying it, then injecting roof-and-gutter sealant with an applicator gun.

If the leak persists, you will have to dismantle and reseal the joint. Wear strong gloves to protect your hands from rough metal.

  • Ladder with a stand-off bracket
  • Gloves 
  • Safety goggles 
  • Spanner
  • Hammer
  • Wire brush
  • Old chisel 
  • Small trowel 
  • Paintbrush 
  • Narrow-bladed filing knife
  • Perhaps a junior hacksaw and nail punch
  • Metal primer
  • Roof-and-gutter sealant
  • Nut and bolt of correct size

1. Undo the nut securing the bolt in the joint piece.  If the nut will not move, cut through the bolt with a hacksaw and take out the shank with nail punch and hammer.

cutting gutter bolt

2. Gently hammer the joint piece to separate it from the gutter sections.

3. With the joint dismantled, chisel away any putty and clean off rust with the wire brush. Scoop away the debris with the trowel.

chisel gutter rust

4. Apply a coat of metal primer to the gutter ends and the joint piece and leave it to dry.

5. Spread roof-and-gutter sealant onto the joint piece and reposition the gutter sections on it.

spreading the sealent

6. Secure the joint with the new nut and bolt.


Plastic gutters

Where pieces of gutter join, or connect with a downpipe, they are clipped to a connector or union piece which has gaskets in it to make the union watertight. Leakages caused by dirt forcing the seal slightly apart can be cured by cleaning. Squeeze the sides of the gutter inwards to release it from the union piece. But if there is no dirt, the gaskets may need renewing.

  • Ladder with a stand-off bracket 
  • Filling knife
  • New gaskets or roof-and-gutter sealant.

1. Squeeze the sides of the gutter sections in order to release them from the clips of the union piece.

2. Gently raise the end of each section of gutter in turn until you can see the gasket in the union piece. Peel the gasket away.

installing gasket

3. Fit the new gaskets, pressing them well into place. Alternatively, fill the grooves for the gaskets with sealant.

4. Gently squeeze each gutter section in at sides to ease it back into the union piece clips.