Roof vents / mushroom vents.

[Beardy]

Had a bit of a oops moment whilst cleaning the caravan last week (2016 Lunar Venus). The support spigot pushed straight through the dome on the vent because the plastic had turned brittle. It took next to no pressure to snap the plastic. I've just been out and changed both vents, not a major job, two hours from start to finish being very meticulous and removing every trace of the old silicon (plus a couple of hours last week trying to work out how to get a panel off to remove the microwave to access one of them ). Around £30 in total but I guess it would have cost £100+ to pay a service centre to replace them.
When I was looking for new vents on line there didn't seem to be many variants, two designs in a couple of different sizes so I'm guessing that the majority of caravans / motorhomes use the same ones. My caravan is 7 years old and has spent some of its life under cover (it came with a cover when I bought it so I assume that it has).
Long preamble, but my question is do these vents need replacing regularly or have I been unlucky in that the vents fitted were sub standard plastic? I'm thinking about slapping a good dollop of car wax on the new ones once the sealant is dry to give them some added uv protection.

 

[otherclive]

I never had to replace any but being plastic they will age with time and as you experienced they can break. My longest ownership was new caravan 2005, sold nine years later, and 2012 caravan sold 2021.

 

[Dustydog]

Mine are 15 years old. They are brittle, fragile and have been repaired twice by me with epoxy resins. If the mountings break again then new ones will be required. Typical caravan fixings all built not to last!🤪

 

[Beardy]

Mine are 15 years old. They are brittle, fragile and have been repaired twice by me with epoxy resins. If the mountings break again then new ones will be required. Typical caravan fixings all built not to last!🤪

I did think about a repair but figured that they'd still be brittle and would break again the first time I touched them, or break off in transit and I wouldn't know until I saw the puddle inside the caravan. After removing the first I saw that the dome is screwed onto the base, you could get away with just replacing that (the base was pretty solid as the dome shields it from sunlight). You may find though that when you unscrew the fitting from inside the caravan the base lifts away from the roof if the sealent has lost its adhesion, both mine did.

 

[Raywood]

Unlucky but it happens. We had one Coachman model 10 years and did not have that one but that was some time back. Possibly they don't make vents like they used to do!