roof vent - replacement with panel

[ambivert]

I want to replace my roof vent with a flat square panel. Don't tut... I have my reasons
What's the best material to use?
Same material as the roof maybe so it expands by same amount when it warms up?
The roof is a fibreglass poptop btw.
I've got some perspex sheet. Any good ya reckon?

[MattBW]

I wouldn't recommend it personally, you genuinely need that ventilation in a camper van and I spent hours undoing a "perspex replacement" on my van a few months ago.

The perspex would mist up very quickly when I was in the van, and when cooking it would literally drip with condensation. The previous owner just did it because a vent was 50quid, but it looked awful and caused problems and also when cooking without a vent the CO monitor wouldn't take long to go off.

Personally I would just put a vent back in, I realise you have a reason but they put vents in for a reason too.