What Decorators Need to Know About Polycarbonate Roofing
If you've ever painted a conservatory in July, you'll know exactly what the problem is. The room turns into an oven, your emulsion dries on the roller before you can lay it off, and the homeowner keeps popping in to ask why every window is open.
Nine times out of ten, you're working under a polycarbonate roof. It's one of the most common conservatory roofing materials across the UK, and while nobody's expecting you to become a plastics expert, picking up a few basics will save you time on site and help you dodge those awkward conversations with customers.
Twinwall, Multiwall and What You're Actually Working Under
Most domestic conservatories will have either twinwall or multiwall polycarbonate sheets overhead. Twinwall is the simpler of the two. It's got two layers with a single row of hollow channels running through the middle. Multiwall adds a third layer (or more), which gives it better insulation and a bit more stiffness.
What does this mean for you as a decorator? It comes down to how much heat and light the roof lets through. Twinwall is thinner and cheaper, so you'll see it on older conservatories and lean-tos more often. It lets in more heat and more UV light. Multiwall does a better job at keeping temperatures under control, but even a decent multiwall polycarbonate roof won't come close to performing like a tiled or glass one.
The bottom line is that you're working in a space where the temperature can jump by 20 degrees between morning and afternoon. That's the bit you need to plan around.
How Temperature Swings Affect Your Finish
Polycarbonate conservatories trap heat in summer and lose it fast once winter hits. On a sunny day, the internal temperature can easily reach 35°C or higher. In winter, it can drop to single figures overnight, even if the heating's been on.
Both extremes will cause problems for your finish. When it's too hot, water-based emulsions dry far too quickly. You'll end up with visible roller marks and lap lines everywhere because the paint is skinning over within seconds. You just won't get a decent lay-off in those conditions. Cold weather brings its own issues too, slowing drying time right down and sometimes stopping the paint from curing properly, which leaves you with a soft, tacky surface.
The fix isn't complicated. During summer, try to work early in the morning or later in the afternoon once the sun has moved off the roof. In winter, make sure the room's been heated for a good few hours before you pick up a brush.
Don't Wreck the Panels When You're Cleaning Up
There'll be times when you need to clean a polycarbonate roof before or after a job, especially if you've got paint overspray or dust sitting on the panels. This is where a lot of people slip up.
Polycarbonate scratches really easily. Never go near it with abrasive cloths, scourers or anything with grit in it. And stay well clear of solvent-based cleaners. White spirit, acetone and even some multi-surface sprays can cloud the surface or crack it outright. Your best bet is warm water with a drop of washing-up liquid and a soft microfibre cloth. If the panels are particularly filthy, give them a rinse with a hose first to knock the worst off before you start wiping.
When a Customer Asks About Yellowed Panels
This comes up way more than you'd expect. A homeowner spots that their roof panels have turned yellow or hazy, and because you're the tradesperson standing right there, they'll ask you about it.
The yellowing is down to the UV-protective coating on the outside of the sheet breaking down over time. Most polycarbonate sheets come with a UV layer bonded to one side, and once that degrades, the material underneath starts to discolour. Cheaper panels, or ones that were installed with the UV side facing the wrong way, will yellow much quicker.
You can't fix it with a clean, no matter how thorough you are. If the panels have gone noticeably yellow or they've gone brittle, they'll need replacing. That's a job for a roofer or glazing specialist, but knowing the cause means you can give the customer a proper answer instead of just a shrug.
The Short Version
Polycarbonate roofing is everywhere in domestic conservatories, and it creates working conditions that can genuinely mess with your results. Keep an eye on the temperature before you start and keep solvents well away from the panels.
And when a customer asks why their roof has gone yellow, you'll actually have a proper answer for them. None of it is complicated, but knowing this stuff is what sets a clued-up decorator apart from someone who's just making it up as they go.
For more such useful information read our site crackstube.blog