Brackets and joints that have let go
A gutter run is built from lengths joined with fittings: unions, stop ends, corners and the outlet to the downpipe. Each joint depends on a rubber seal or a bead of sealant. When the seal ages, or the gutter has been knocked and moved, water seeps out at the joint instead of travelling along the run. The tell-tale is a drip from one spot, or a dark stain on the fascia directly beneath a union.
Brackets matter just as much. A conservatory eaves is low, so people lean ladders against it, hang plant baskets from it and brush past it with a ladder on the way to the house roof. A bracket that has loosened lets the gutter sag between supports, and a sagging gutter opens its joints further.
Look for three things from the ground or a stepladder: a gap at a union, a stop end that has popped out, and a bracket that no longer touches the gutter. Any of them points to a repair of the fitting itself, which is a small job, rather than a new run. Check the fascia behind the gutter as well, since a soft or split board will not hold a bracket however often it is refixed.
Fall, debris and the outlet
Gutters work because they slope. Brett Martin, the gutter maker, sets the fall at 1mm for every 600mm of run. That is a gentle slope, easy to lose when a bracket drops or a fascia moves. Once a stretch holds a shallow pool, water has nowhere to go but over the front lip or out of the nearest joint.
Debris does the same job from the other direction. Leaves, seeds and grit settle at the lowest point, usually right beside the outlet, and build up until the opening is blocked. Then the gutter fills in a downpour and overflows against the conservatory wall or the roof edge. Which? Trusted Traders (Nov 2025) put clearing every gutter on a property at £75 to £350, a typical UK range ex VAT, and add that South East prices run higher.
A quick test is to pour a jug of water in at the far end and watch it travel. Water that runs freely to the downpipe suggests the fall is fine and the fault is a joint. Water that stops and pools tells you where the run has dropped, and where to put the level.
Moss and run-off from the house roof
Many conservatories sit directly below the main roof of the house. Anything that comes off the house slope lands in the conservatory gutter. Moss loosened by rain, granules, small bits of mortar and leaves from nearby trees all arrive in a stream, and a small-bore conservatory gutter has less capacity to carry them than the main gutters do.
That makes the house roof part of the diagnosis. If the conservatory gutter fills quickly, look up at the tiles or slates above it. A slope heavy with moss, or a run of tiles shedding grit, will keep refilling a gutter you have just cleaned. Cleaning the moss at source is the sensible next step, and our guide to cleaning a conservatory roof covers the glazed roof underneath.
If water also pours in at the join with the house wall, the cause may be a roof junction rather than the gutter. The wall flashing page explains how to tell, and what to look for on the wall itself. A stain that starts at the junction and runs down the brick points that way.
Fixes, in general terms
The right fix follows the fault, so this is the order in which we work through a leaking conservatory gutter:
- Clear the gutter and the outlet, and flush the downpipe so you know water leaves freely.
- Refit loose brackets so the run sits to the fall again.
- Replace a perished seal or a cracked union rather than smearing sealant over it.
- Replace a short length that has split, matching the profile so the fittings still marry up.
A whole new run is only the answer when the gutter has gone brittle or several lengths have failed together. MyJobQuote (20/10/26) puts gutter replacement on a house at around £1,000 to £1,600, a typical UK range. That is not a conservatory figure, so treat it as a guide to scale only.
The gutter sits at the edge of the roof, so it is looked at when the roof is. Our repair page sets out what a visit involves, and the conservatory roofs service covers the rest. One written price comes once the survey is done.
