Conservatory Leaks and Draughts: How to Solve Them

A conservatory that leaks when it rains or feels draughty on a cold day quickly stops being the sunny spot you built it for. The reassuring news is that most leaks and cold spots trace back to a handful of usual suspects, and some are a simple conservatory window repair DIY job. Here is how to find the source and put it right, and when to call in a specialist.

Start by tracing the source

Water and draughts are sneaky. Where you see the damp is often not where it is getting in, because water runs along frames and beams before it drips. Before sealing anything, do a bit of detective work:

• Watch during rain. Note exactly where water first appears and how it tracks.
• Feel for draughts on a windy day. Run your hand around frames, opening vents, doors and the roof line to find the cold spots.
• Check high versus low. Water or draughts up high often point to the roof, flashing or roof glazing. Problems lower down usually mean frames, seals or drainage.

Patient tracing saves you resealing the wrong thing and wondering why the leak came back.

The usual causes of leaks

Most conservatory leaks come from one of these:

Blocked drainage

The most common culprit by far. uPVC frames and box gutters are designed to drain water away through weep holes and channels. When these clog with leaves and grime, water backs up and overflows indoors. Clearing them is often all it takes.

Failed seals and silicone

Rubber gaskets perish and silicone cracks over the years. Once the seal between the glass, frame, sill or wall breaks, water finds its way in. Reseal work fixes a lot of low-level leaks.

Flashing problems

Where the conservatory roof meets the house wall, a strip of flashing seals the joint. If it lifts, cracks or was poorly fitted, water runs straight down the wall and in. This is a common source of stubborn leaks and is a job for a specialist.

Failed roof glazing

Cracked panels, slipped roof glass or degraded seals in the roof let water through from above. Roof work is not a DIY job, as it means working at height on a fragile surface.

The usual causes of draughts

Cold spots have their own common causes:

• Worn or shrunken frame seals, so cold air whistles in around vents and doors.
• Gaps where the frames meet the base or dwarf wall, especially in older conservatories.
• Single-skin polycarbonate roofs, which do little to hold heat and let the room run cold in winter.
• Draughty or misaligned doors that no longer pull tight onto their gaskets.

A conservatory that is freezing in winter and roasting in summer often has a glazing and sealing problem rather than a heating one.

What you can fix yourself

Several of these are within reach of a confident homeowner:

• Clear the drainage. Brush out weep holes and clean the gutters and box gutters.
• Renew perished gaskets and re-silicone cracked joints with exterior-grade sealant.
• Fit draught excluders to doors and adjust hinges so they close tightly.
• Lubricate and adjust stiff vents and handles.

If clearing drainage and refreshing seals does not solve it, the problem is likely at the roof or flashing, which is where a professional comes in.

When to book a repair

Call in help when the leak or draught points to something bigger:

• Water coming from the roof, flashing or high up the wall
• Cracked or slipped roof panels
• Frames that have dropped or moved
• Damp spreading into the house wall or plaster

These need proper assessment and, in the case of roof work, the right access equipment. Our conservatory and orangery team in York can advise on tired conservatories, and our window and door repair service handles seal, glazing and draught work across North Yorkshire.

Rough 2026 costs

Prices vary with the job and access, so treat these as broad 2026 guides rather than a quote. Reseal and gasket work is usually modest. Replacing a misted or cracked glazed unit often lands around 150 to 400 pounds depending on size. Flashing and roof repairs vary widely. For a figure based on your conservatory, request a free quote and we will come and take a look.

FAQs

Why does my conservatory leak when it rains?

The most common causes are blocked drainage, failed seals or silicone, and problems with the roof flashing. Clear the drainage first, then check the seals, and note where the water appears to narrow it down.

How do I stop draughts in my conservatory?

Renew worn frame seals, re-silicone gaps, fit draught excluders to doors and adjust them to close tightly. If the roof is single-skin polycarbonate, upgrading the glazing makes a bigger difference.

Can I fix a conservatory leak myself?

Often yes, if it is down to blocked drainage or failed low-level seals, which are reasonable DIY jobs. Leaks from the roof or flashing need a specialist, as they involve working at height.

Why is my conservatory so cold in winter?

Usually worn seals, gaps at the base, or a single-skin roof that holds little heat. Sealing up draughts helps, and better glazing or a warmer roof solution makes the room usable year-round.

Want to see the full range of conservatory and glazing options? Download our latest brochure, or request a free quote and we will come and take a look.