By Shaun, Shelfbank Windows. Published .
Condensation is one of the most common complaints about conservatories in winter. On a cold morning the glass and the roof can be running with water, and over time it can lead to mould on the seals, damp patches and a musty smell.
The good news is that most of it can be reduced. This guide explains why it happens, what you can do day to day, and when the structure of the conservatory is the real problem.
Why conservatories get so much condensation
Condensation forms when warm, moist air touches a cold surface. The air cools, it cannot hold as much moisture, and the water settles on the surface as droplets.
A conservatory has a lot of cold surfaces. The glass, the frames and especially a polycarbonate or older glass roof lose heat quickly on a cold night. Meanwhile, moist air from the house drifts in through the open doors, or is created in the conservatory itself.
Along the Welsh border, the damp, mild weather we often get in late autumn and winter does not help, as the outside air is rarely dry.
Common sources of moisture
- Drying washing indoors, which puts a large amount of water into the air.
- Plants, especially lots of them in a closed space.
- Moist air from the kitchen or bathroom drifting through the house.
- Unflued gas or paraffin heaters, which produce water vapour as they burn.
- Pets' water bowls, fish tanks and other open water.
Simple ways to reduce it
- Ventilate. Open the trickle vents or a roof vent for part of the day, even in winter. A small amount of fresh air makes a big difference.
- Avoid drying washing in the conservatory.
- Keep the temperature steadier. Big swings from warm to cold make condensation worse.
- Keep the door between the house and the conservatory closed if the conservatory is unheated, so warm, moist air from the house does not reach the cold glass.
- Wipe the glass and frames in the morning, and keep the drainage slots in the bottom of the frames clear.
- Use a dehumidifier if the room stays damp.
When the problem is the structure
If you are doing all of the above and the conservatory still runs with water, the cause is usually the building itself.
The roof
Polycarbonate roofs and older glazed roofs lose heat quickly, so the inside surface gets very cold. A lot of the condensation and dripping in conservatories comes from the roof. Replacing it with an insulated, solid roof keeps the inside surface much warmer. Our post on putting a solid roof on a conservatory explains what is involved.
Failed double-glazed units
If the condensation is between the two panes of glass rather than on the inside, the sealed unit has failed. That will not clear and the unit needs replacing.
Leaks that look like condensation
Water that appears in the same place after rain, or runs down a wall or along a glazing bar, may be a leak rather than condensation. Gutters, flashing where the roof meets the house, and roof seals are the usual places to check.
Why it is worth dealing with
Persistent condensation can lead to black mould on seals and in the corners of the frames, damp plaster on the house wall, and damage to furniture and blinds. Mould on seals and in frame corners can usually be cleaned off, but it will come back if the moisture is not dealt with. It also makes the room less pleasant to use, which is often why conservatories end up as storage over winter.
Talk to Shaun
If condensation is making your conservatory unusable, see our warm roof replacements and conservatories pages. I cover Welshpool, Ellesmere, Oswestry and the surrounding towns. Call Shaun on 07815 753361 for a free site survey and a fixed written quote.
Related services: Conservatories, Warm Roof Replacements.