Can you spray uPVC in winter in Plymouth? The honest answer on what we can do November–March, what waits for April, and our winter workshop workaround.
Plymouth winters aren't Norway — but we get rain, dew, salty coastal damp and cold snaps that drop surface temperatures below the safe spraying threshold. Here's an honest breakdown of when we can and can't spray uPVC outdoors, and what we do when the weather won't cooperate.
Yes — we spray uPVC outdoors all the way through winter as long as the surface temperature is above 8°C, the relative humidity is below ~85%, the dew point is at least 3°C below the substrate temp, and rain isn't forecast for 24 hours after spraying. In Plymouth this gives us viable spraying windows most weeks of the year, even in January. Big jobs may be staged across multiple dry windows.
Cold uPVC contracts and contaminates with cold-bonded moisture. Below 8°C, the primer doesn't cure properly and the topcoat doesn't form a continuous film. We carry a contact thermometer and check the actual frame temperature, not just the air. South-facing walls in winter sun often reach 12–18°C on a clear day even when the air is 6°C.
Air humidity affects how paint atomises and how solvents flash off. Above 85% — common in Plymouth winter — paint dries with a hazy finish and reduced adhesion. We measure RH at every job.
If the substrate is colder than the air's dew point, a thin film of moisture forms on the surface — invisible to the eye. Paint applied over that fails. We need at least 3°C of margin between substrate temperature and dew point.
The first 24 hours after spraying are the critical cure window. Rain on uncured paint causes bloom, streaking and adhesion failure. We watch the Met Office and the Plymouth Marine forecast — both — before committing to a job day.
Often the best autumn window. Cool but not cold, dry days are common, dew point is manageable. We finish a lot of jobs in late October and early November.
Mixed. We can spray on dry, mild days — and Plymouth has them more than people realise. We won't spray in fog, sleet or sustained rain. About 50–60% of winter weeks have at least one viable spray day. Bookings get bumped around the weather, not cancelled.
Tricky. Variable. We pick our days carefully. Demand is also high as people want their windows done before summer, so we book up fast.
Peak. Long dry windows, low dew point, easy. Most large jobs get scheduled here.
Even when outdoor uPVC won't go ahead, we can still work on:
For customers booked in winter where outdoor uPVC keeps getting weathered off, we can sometimes remove the front door, take it to the workshop, spray it indoors, and refit the same day. This guarantees a January spray of at least the front-of-house focal point. We can't do this with whole windows (they stay put, obviously), but it covers off the most visible bit.
Yes — provided we hit the four conditions above. The cured film is identical. The risk in winter isn't paint quality, it's having to wait for the right day.
For anyone whose project isn't urgent, April through October is the smoothest experience. Quotes are valid for 6 months, you can book in March for May, and we can guarantee the spray window.
Yes, on dry mild days with the right surface temperature, humidity and dew point. Plymouth has more viable winter days than people expect — about 50–60% of weeks have at least one suitable day.
Yes — provided we wait for proper conditions (8°C+, RH below 85%, dew point margin, no rain for 24 hours). The cured film is identical to summer work.
We reschedule. We never spray in marginal conditions — the paint doesn't cure properly and the job fails. We hold the slot until the next dry day.
Often yes. We remove the door, spray it in the workshop and refit the same day. Useful for guaranteeing a winter front-of-house spray when outdoor work is weathered off.