Why is my gutter sagging, and can it be refixed?

An empty plastic gutter weighs little. A full one does not. Water, wet leaves and silt add up quickly along a length of channel, and all of it hangs from a few brackets screwed into the fascia. Winter adds ice, which expands and pushes at joints and fixings.

So the load a gutter must carry is not its own weight but the weight of what sits in it. Cast iron is heavier before any water arrives, which is why those runs ask more of both the brackets and the board behind them. Our page on cast iron gutters explains what that means for fixings.

Wet leaves are worse than dry ones. A gutter that looks only half full of sodden debris can be carrying far more than you would guess, and the weight sits right at the front lip, which is the part that bows first.

Brett Martin's installation advice allows supports no further than 900mm apart, and closer than that, at 600mm, where heavy snow is expected. FloPlast's MiniFlo guide sets 500mm as the widest gap between fascia brackets on a straight run. The figures belong to different systems, so check the maker's data for the gutter you actually have.

Either way, spacing is a maximum, not a target. Extra brackets near joints, corners and outlets are good practice, because those points take the most load. If you can count brackets along a run and the gaps look wide, that explains the dip. A short section that droops between two brackets can often be cured with one more fixing, provided the board will hold it.

Brackets work loose over the years as screws back out or the timber around them softens. Tapping a screw into the same hole rarely lasts. The reliable repair is a new bracket fixed into sound timber, ideally at a rafter end.

The fascia itself is the other suspect. Timber kept damp season after season turns soft, and the screws then pull out under load. Press a screwdriver tip into the underside. If it sinks, the board is no longer a fixing. Fitting a cover over the top, known as capping, hides this but does not cure it, as our page on fascia capping explains.

Ladders leaned against the gutter bend it too, which is a good reason to use stand-offs, and a good reason to ask a visiting trade how they intend to reach the eaves before they start.

A gutter that has pulled away at one end can fall, taking its load of water and debris onto a path or doorway. If a section is hanging loose, keep people away from underneath and do not try to prop it with timber or climb up to push it back.

Tell a roofer what you see, and send a photograph. A temporary support or a careful removal of the loose length can make the area safe until the proper repair. Heavy cast iron is a particular hazard, and a falling length can injure someone badly.

A clogged channel sags because it is heavy, and a sagging channel clogs because water pools in the dip. The cycle feeds itself. Clearing the run is the first step, and it often shows how far the gutter has dropped. Restoring the line matters, because plastic systems are laid with a slope of roughly 1:600 to 1:350 and a dip breaks it.

A guard keeps leaves out, but it will not hold up a run with weak fixings, as our article on gutter guards notes. Fix the support first, then decide about guards, and think twice before loading a weak run with anything extra. The fascia's age matters as well, which is covered in our guide to the lifespan of uPVC fascias.

The roofer lifts the gutter out or releases it at the brackets and clears everything inside. The fascia is checked for soft patches. A string line or level is then stretched along the board to set the slope, and new brackets are fixed at the right spacing, into sound timber, ideally at the rafter ends.

The gutter goes back, the joints are checked and re-sealed where needed, and the run is tested with a hose to prove the water goes to the outlet and not the dip. This takes little time on a single run, and it is the only repair that lasts.

A quick job that merely props the sagging part or adds one screw at the lowest point rarely holds through a winter.

When the gutter is sound and the board is firm, refixing at the right spacing is a small job. When the channel itself has bowed or gone brittle, replacement is the better call. MyBuilder's guide, updated in August 2026, gives guttering replacement at £30 to £70 per metre as a national range, and a tall elevation adds access cost to that.

We photograph your own gutter on the survey and send a written quote afterwards. Sometimes a refix is all it needs, and then that is all we propose. The work carries a 10-year workmanship guarantee in writing, and we leave the site clear. See our gutters, soffits and fascias service, or ring 01793 626096.