A leaking gutter is one the most common causes of isolated damp in UK homes, even though it is one of the easiest to spot early and to fix quickly. Sometimes you will be able to see water leaking from a gutter from inside the house, but often you will not notice the leak until it starts to make a dark stain on the wall. If this is left, moss and algae may start to grow and the water may start to penetrate the wall and cause problems inside the house.
To spot signs of leaking gutters early, periodically take a look around the house when it is raining and see if you can spot any water dripping or running down the wall (more than just the rain of course). Most often the leak is from one of the joints in the guttering, and should be fixed as soon as possible.
Leaking Metal Gutter Joints
Metal gutter sections, both steel and cast iron, are usually sealed at the joints and then a bolt is put through the joint to further strengthen it. These bolts are very often corroded so much that they will not undo. In some cases, a leaking joint can be fixed by injecting roof and gutter sealant into the joint with an applicator. Leave this to harden and test it by pouring water along the gutter for a few minutes. If this has fixed the problem, you can put the ladder away and make a cup of tea. If not, you will need to cut through the bolt with a hacksaw, flush with the bottom of the gutter, and remove it.
You should now be able to gently tap the joint piece with a hammer and separate the two sections of the gutter at the newly freed joint. You might need to gently tap one of the sections with a hammer if the seal is still holding them together, but be careful not to damage the gutter, especially with cast iron guttering on old houses. Now you can see the inside of the joint you can clean away all of the sealer putty and any rust using a wire brush. If the putty is very difficult to shift, use a sharp chisel or a flat-bladed screwdriver to scrape it away.
Paint the cleaned ends of the guttering and the joint piece with metal primer and leave them to dry completely. Spread a generous layer of roof and gutter sealant onto the joint piece and on the ends of the gutter sections where they will overlap. Fit the two sections together and fit them into place on the joint piece. Finally insert a new bolt through the original hole and screw it tight.
Leaking Plastic Gutter Joints
Sections of modern plastic or PVC guttering fit together, either at the point of a downpipe or along the run, in small sections called Union Pieces. The union pieces feature a rubber gasket which the gutter section sits on top of and thereby forms a seal. If a joint on a plastic gutter is leaking it is probably the gasket which is at fault. Either dirt has been forced between the gutter and the gasket and created a break in the seal, or the gasket is worn and needs to be replaced.
To release a section of gutter from the union piece, squeeze the sides of the gutter inwards until they are free of the two lips on the union piece that hold it in place. You will then be able to lift the gutter away from the union piece and should see the rubber gasket beneath. If dirt between the gasket and gutter is the problem, simply clear it away and replace the gutter section firmly back into place. If the gasket is worn or corroded, peel it away from its housing in the union piece and replace it with a new one.
If you cannot find a new gasket to fit your gutter, you can try filling the now empty gasket housing with a thick bead of roof and gutter sealant (or even silicone sealant) and then pressing the gutter into the union piece. If you have had to resort to this kind of fix, it is worth applying another bead of sealant beneath the gutter where it meets the union piece.
If, when it rains, you can see water spilling over the sides of a section of gutter, then you probably have blockage in the gutter. This will probably be leaves or other natural debris, but could be anything from a tennis ball (if you have kids in the house) to an old birds nest. Whatever the case, you need to get up a ladder and clean it out. Water spilling over the side of a gutter for any length of time will cause damage just as easily as water leaking from a joint will.
Before clearing the blockage it is a good idea to place a piece of hardboard or thick cardboard over the gully or drain at the bottom of the downpipe in that section. If you don’t, any blockage that you dislodge could wash down the downpipe and block up the gully or drain. Scoop out whatever is blocking the gutter using a trowel, being careful not to spill muck down the walls and trying not to let too much go down the downpipe.
Most modern plastic gutter allow for the fitting of leaf guards, plastic grilles which fit over the top of the gutter and stop them getting filled up with leaves and other debris. This is particularly useful if part of your guttering is overhung by trees.
You can make your own leaf guard using chicken wire bent into a long curve and placed over the top of the gutter. If you do this, it is a good idea to secure it by drilling holes just below the rim of the gutter and securing the wire with cable ties or similar.