Gap between tub and wall

A lot of this in model dependent. The underside of our tub is situated such that there is considerable air flow between tub, kitchen sink and even the pantry. Others are not so open.

I would check to see is if there is a lip on the tub edge that extends up behind the back wall.

wing_zealot wrote:
I googled it. I found three, this one, one from 2012 that said they had mold growing in the gap, and one from 2010 where people basically said they caulked it themselves.
P.S. mine came from the factory caulked despite what you suspect. Maybe mines built so there is no need to worry about condensation behind the walls.

You used the Google search feature for this site, globally, there are many more discussions on this topic. Sorry, I didn't mean to imply yours it's designed differently than the Duo-Form brand tubs in most of the Jayco's I have seen.

The tub portion extends high enough behind the surround that caulking is not required to prevent leaks so that is not done at the factory thus saving a couple of dollars. I calked mine as I found that enough water would stay on the lip to dribble on the floor when the TT was moved. The two hoses mentioned are the low point drain for the water system

I googled it. I found three, this one, one from 2012 that said they had mold growing in the gap, and one from 2010 where people basically said they caulked it themselves.
P.S. mine came from the factory caulked despite what you suspect. Maybe mines built so there is no need to worry about condensation behind the walls.

wing_zealot wrote:
Mine's caulked. And why would there be moisture behind there in the first place unless you have a leak? And why would you need such a big gap? You expecting to drain a torrent of water?

Google "RV tub gap" and you will find tons of threads on this. I suspect someone other than the factory caulked your tub if it's not the overlapping design. I guess the theory is condensation trapped behind the wall will promote mold growth and the air gap allow that moisture a place to vent.

I have found threads discussing the same thing in home shower installs where some builders will not caulk small areas for weeping.

Mine's caulked. And why would there be moisture behind there in the first place unless you have a leak? And why would you need such a big gap? You expecting to drain a torrent of water?

Generally the bottom portion of shower extends up aways and water can't run up hill therefore no need for caulking. The red blue hoses are low point drains to aid in draining water lines for winterizing

No. That gap is to ventilate the cavity behind the shower wall in case moisture is trapped behind it. My Jayco is the same way.