A month or so ago while checking the caulking on the roof I noticed that the shower skylight was cracked. I then read on here that they had an installation problem and were replacing them. I called the dealer who ordered one and when it came in I put it on. While changing it I found out that there was no "inner" skylight. On all my previous Rv's there was both an inner and outer skylight. My next thought was ...what a heat loss/absorption area! Only 1/8" of polycarbonate between inside and out! My plan was just get a sheet of plexiglass, cut it to fit inside the trim and have an insulated/air sealed space.
Last weekend while walking under the chin I noticed water dripping out of the skirting near the landing gear on the street side. It hadn't rained in a while. I looked for cracked caulking on the chin trim unsuccessfully. I was in the middle of a project and figured I'd return to it later. Yesterday while in the local HD, I walked by the plexiglass...(light bulb came on). So I grabbed a sheet.
I got home and pulled the trim down to get a measurement. I was shocked! I just figured out where the water down by the landing gear was coming from! When showering the steam was condensing on the interior of the skylight then running down the inside of the trim and into the sheathing on both sides of the framing. It was totally soaked! I hit it with the blow gun on the compressor and blew out a measurable amount! Enough to collect in the bottom of a brandy glass! After getting it dried out fairly well I slid the plexiglass up into position and then put the trim back on. I then caulked the trim to the plexiglass. Now the water that collects on the plexiglass will run down the trim and back to the shower. Check yours out too! I'm sure I'm not the only one that has had this problem!
2015 GMC Denali DRW
2014 Dynamax Trilogy 3715FB