Inspired by a helpful YouTube guide. We based this walk-through on the popular UK video "Leaking Conservatory Roof — ASB #30", from the Skill Builder channel — a well-respected UK trade channel with practical, no-nonsense guidance. Their systematic approach to tracing the leak source rather than guessing is exactly the right way to tackle it.
1. Trace the leak to its actual source
On a dry day, get a helper to pour water slowly onto different parts of the roof with a hose while you watch from inside. Start at the ridge and work downwards — leaks almost always enter higher up than where the drip appears.
Check the junction between the conservatory roof and the house wall first. The flashing or sealant at the wall plate is the single most common leak point on UK conservatories, particularly those that have been standing for more than ten years.
2. Inspect and reseal the wall flashing
The wall flashing sits where the conservatory roof meets the house wall. On older installations this is often just a bead of silicone or mastic that has dried, cracked, and pulled away. On others it is a lead or aluminium flashing that has lifted or delaminated.
Remove the old sealant completely with a scraper and white spirit. Clean the surfaces, allow them to dry, and apply fresh low-modulus silicone sealant — the type rated for conservatories and roofing. Press it in firmly with a wet finger and allow it to cure for at least 24 hours before testing.
3. Check the ridge bar and end caps
The ridge bar runs along the apex of the roof and holds the tops of the glazing bars together. The rubber gaskets inside the ridge cap harden and shrink over time, allowing water in. End caps — the pieces at the gable ends — are another common point.
Remove any end caps, clean out any old dried sealant, and apply fresh silicone before replacing. If the gaskets inside the ridge are visibly cracked or missing, they can sometimes be replaced; replacement strips are available from conservatory parts suppliers.
4. Check where the panels sit in the glazing bars
On polycarbonate roofs, each panel sits in a glazing bar with rubber gaskets or neoprene tape holding it watertight. These degrade and compress over time. Run a finger along each glazing bar joint — if you can feel gaps or hear the panel rattle, water can get in there.
Self-adhesive glazing tape is available to reseal these joints without dismantling the roof. Clean and dry the joint first, then press the tape firmly along the full length. It is not a permanent fix but will extend the life of the roof considerably.
5. Clear the gutters and check the eaves
Blocked gutters cause water to back up and overflow into the conservatory. Clear any debris from the gutters running along the eaves and check that they fall correctly towards the downpipes — a length of gutter that has sagged or pulled away from its brackets will hold standing water that eventually finds its way in.
Check the seal between the gutter and the fascia. On many conservatories this joint relies on a rubber strip that compresses when the gutter is fitted, and once that strip has gone, water weeps in behind the fascia.
6. Inspect the polycarbonate panels themselves
Cracks in polycarbonate are less common than seal failures but do happen, particularly on older panels that have become brittle with UV exposure. Hold a torch inside on a dark day and look for light coming through anywhere it should not.
Small cracks can be sealed from above with roofing silicone as a temporary measure. A panel that is significantly crazed or cracked throughout is worth replacing — polycarbonate panels are available by size and can usually be slid in and out of the glazing bars without a full roof rebuild.
When to call a handyman
If you cannot find the source of the leak, or if the roof structure itself has shifted — ridge sagging, rafters pulling away from the wall plate, frames out of square — that is a job for someone who can get up there safely and assess it properly. Some leaks are genuinely difficult to trace, and a fresh set of eyes often finds them quickly. Richard can investigate and sort the repair in a single visit for most common conservatory roof issues.
Conservatory roof leaking?
The Sandwich Handyman can find and fix conservatory roof leaks, reseal flashings, and sort ongoing maintenance issues around your property in Sandwich and the surrounding area.
Contact Richard