kennyd63 wrote:
My question is there a way to prevent your vent covers on the roof from getting brittle do the exposure to the elements?
UV radiation will breakdown any material in direct exposure and vent lids or covers (or the other parts of your trailer) are no exception.
The only way to prevent them from getting brittle would be to shield them from the source of the embrittlement, i.e. cover them up with a barrier that is impervious. It is for this reason I store my RV under cover. With your trailer's exposure to the elements I am afraid you have to decide between the lesser of two evils.
If I were you, I would put on cheap smoke-coloured vent covers over the vent lids and let them be the sacrificial part that gets brittle and not the vent lid, which would probably be harder to replace and have a simiar cost. Then when the vent covers do deteriorate just swap them out with a new one.