Why Is My Gutter Sagging?

A gutter hangs from brackets fixed to the fascia, and the plastic or metal between them has to bear the weight of whatever it carries. Water is heavy. A full run of gutter can hold a considerable load before it reaches the downpipe, so brackets set too far apart let the span between them bow downward under rain.

Makers publish their own maximum spacing for each system, and the instructions for the brand on your house are the guide. A run that has lost a bracket, or one where a bracket has snapped, is just the same as a system that was fitted with gaps that were too wide. Look for a smile-shaped curve in the line of the gutter between two brackets, with the low point in the middle of the span.

Extra brackets are the cure here, and the parts are inexpensive. They work only if the board they fix to will hold a screw. That is why the first job on a sagging run is to check the timber, and why bracket spacing is only half of the story. Our answer on the fall a gutter should have explains what happens to the slope once a span has dropped.

When a bracket loosens, the likely reason is that its screw has lost its grip in softened wood. A timber fascia that has been damp for years crumbles around every fixing. The gutter then drops at that point, a gap opens at the next joint and the run starts to lean away from the wall.

A quick check is to lift the lower edge of the gutter gently, or look for screws that hang out of the board. A screw that pulls out without effort tells the story. Pressing a screwdriver into the board's lower edge shows the rest, and our answer on the signs of a rotten fascia board shows how to read it.

Longer screws or bigger plugs will not cure a board that is decayed. They bite into soft material for a short time and then let go. The honest repair is to cut out or replace the rotten length, fix new timber to the rafter ends, and then hang the gutter on firm ground. On plastic fascias the same principle applies to the timber behind them, which may be wet even where the plastic looks perfect. A roofer who lifts the gutter will see which it is.

A gutter full of wet leaves, moss and silt weighs far more than a clean one. Add standing water from a poor fall, and the load on each bracket climbs. Over seasons, the plastic bends, the clips stretch and the whole run settles into a curve that holds even more water, which is a poor cycle to be in.

Snow and ice do the same in a short space of time. Water that freezes in the channel expands, pushes the sides outward and adds weight, and a heavy slide of snow off the roof can bend brackets or pull them from the board. Gutters facing north, or shaded for most of the winter, take the worst of it.

Ladders are the last cause. A ladder rested against the front of a gutter bends it and loosens brackets, and gutters that have been used as a rest for years often show a flat spot or a kink at the same height. If that is the case, clearing and re-hanging the run is usually enough, as long as the plastic has not cracked. The cost of clearing a choked run is covered in what gutter cleaning costs.

A lasting repair has three parts: firm timber to fix to, brackets close enough together, and a slope that drains. For a run that has simply lost a bracket or two on good board, that is a short job from a ladder or tower. For a run that has dragged away from a soft board, the board comes first and the gutter is re-hung after it.

Where the plastic itself is bent out of shape, cracked or brittle, it may not go back, and replacing the affected lengths or the full run is the right answer. Our answer on gutter replacement cost gives the national guide figures.

When you ask for a price, find out whether the roofer will check the board behind, how many extra brackets are planned, how the run will be tested, and whether VAT and any access equipment sit inside the figure. The gutters, soffits and fascias page lists what we do. Ours is a single written sum that follows a survey. Show us the lowest point in the run and tell us how many floors the house has, and we will say what we expect to find.