Greenhouse and Sunroom Glass

Why the interior grows a film

These rooms combine high humidity, strong light and limited air movement, which is a harder version of the same condensation problem an ordinary sealed home has in winter: warm moist air meets a cold glass surface and gives up its water there. Condensation runs down the inside of the glass and pools in the frame channels, and algae establishes in that constantly damp margin before spreading across the pane. In a working greenhouse with plants and regular irrigation adding humidity on top of the structure's own condensation, it happens faster still.

The frame channels matter more than the glass

Water sitting in the bottom channel is what sustains the growth, so cleaning the glass and ignoring the channel means it recolonizes from the edge within weeks. Clearing and drying the channels, and checking their drainage weep holes are not blocked with debris, is the part that actually determines how long the result lasts. A spotless pane over a wet, clogged channel is a temporary fix.

When it's the seals, not the cleaning

If a channel stays wet even after it is cleared and the weep holes are confirmed open, the seal or gasket around that section of glazing has likely failed, letting outside moisture in or trapping condensation with nowhere to drain. That is a structural repair to the glazing system, not something a cleaning visit fixes, and on an older wood-framed sunroom it can mean the glazing bar itself has begun to rot underneath. We will point out when what is needed is a repair rather than another cleaning.

Overhead glass is a different job

Sloped and overhead glazing cannot be worked the same way as a vertical pane. Anything dropped or dislodged falls onto whatever, or whoever, is below, which makes it as much a safety consideration as a technical one, and cleaning solution can drip back down onto the person doing the work in a way it never does on a wall. On older structures the glazing bars and seals may be fragile enough that pressure of any kind is genuinely risky, which calls for a slower, hand approach rather than a fast one.

Polycarbonate is not glass

Many enclosures use twin-wall polycarbonate, which scratches far more easily than glass and hazes permanently under abrasive pads or the wrong solvent. If your panels are plastic rather than glass, that changes what can safely be used on them, and it is worth saying so when booking rather than letting a crew assume standard glass technique applies.