Cabover vent/escape hatch installation

[Panel Pete]

Just in case anyone's curious, here is my original post regarding this tropic.   http://americanclipperownersclub.com/techforum/index.php?topic=2226.0

I wound up purchasing the larger 15" x 22" assembly for better peace of mind as this is the smallest size available with an extruded aluminum frame - the factory size of 13 x 20 is only offered in plastic. I say better peace of mind since my rig had two plastic framed vents (bathroom and above the cabover bunk) and they were both heavily cracked and had actually split through in several spaces. Previous owners had depended on multiple layers of silicone/roof goo to seal up the vents making quite the mess for me to clean off to prep for replacement vents. The aluminum frame won't crack and create the same potential for leaks as the plastic one did and offers a little additional backbone to the cabover roof area - always a good thing in my book.
 
If you have a good grasp on basic wood working skills, are mechanically apt and own or have access to a good selection of tools the job isn't very hard. The following is the step by step approach that I took to complete the job. In total it took me around four hours to do the actual installation, this does not include the two hours or so that I had spent cleaning all the layers of sealant/crap off from around the old vent to prepare it for removal/replacement. Basically, be prepared to spent a full day or two half days doing this job if it's in your future. Anyways, on to the pictures.............


The first picture shows the extent of the damage to one area of the old plastic roof vent.


Second picture is the cabover with the vent removed. Notice the gap in-between the fiberglass roof and the vent frame.


Third picture shows layout for material to be removed.


Fourth image is of the aforementioned roof section removed.   

[Panel Pete]

O.K. now that the fiberglass piece is removed, what do I find......

First Picture shows that the vent frame was made of 2 x 2 and 1 x 2 lumber stacked and stapled. The lumber had been water damaged and the stapled areas were no longer securing the two pieces of lumber together allowing the roof/ceiling to bulge.

Second image shows the random lengths of screws used to secure the hatch - anything from 3/4" to 1 1/2" long. Most were the shorter 3/4" long variety.

Third picture - now for the scary stuff. This isn't what I was expecting to see as the ceiling above the bunk is in great shape with no staining or damage to the factory finish!

Fourth picture shows framing removed and what little was left of water damaged lumber!     

[Panel Pete]

With the old damaged wood out of the way it's time for the new framing..........

First image shows the extent on the rotted wood.

Second image shows the section of fiberglass roof removed.

Third image shows the new larger hole in the roof above the cabover.

Forth picture is of the power planer I used to taper the new lumber to better fit the roofs slope and eliminate the need for the factory installed 1 x 1 firing strips.

[Panel Pete]

And now for the newly framed out larger opening...........

Pictures one thru three show the new frame installed. In these three pics you can also see the gaps in-between the roof/frame/ceiling. These were remedied once the ceiling was re-secured and the hatch was screwed down.

The fourth picture is of the new roof hatch frame screwed in place with 1 1/2" long stainless steel screws after laying a new gasket on the base of the frame with 1" wide butyl putty tape. 

[Panel Pete]

Once the roof vent has been securely screwed in place all that's left is to seal everything up...........

1st picture shows what is used to install any roof vent - butyl tape, proper length stainless steel screws, self leveling dicor sealant, and of course the related tools for the job.

In the second image you can see the taper from the left (front) to right (back) of my clippers roof and the matching taper shape that I planed the boards to. You can also see that the ceiling has been attached to the new framing.

Third and fourth pictures show that now matter how well anyone plans, Mr Murphy can pay you a visit and something can be over looked! I ran out of dicor to seal around the edges! I had one new tube and 1/4 of another that was a remnant from the installation of the vent over my bathroom a few days earlier. Oh well, thankfully my local RV supply store was open the following day and this stuff stays workable for a ridiculous period of time.

[Panel Pete]

Now to finish everything up.............

First picture shows the roof vent fully sealed and all screw heads covered.

Second image is with the roof hatch lid installed

The third and final image is of the finished product from the inside - looks better than ever!

[Panel Pete]

 Every piece of lumber was put together with tight fitting butt joints, a counter sink bit was used to pre-drill all the screw holes, then heavy duty carpentry wood glue (tight bond II) and 2 1/2" deck screws were used to securely pull and hold all the framed joints together. Once dry the same wood glue was used on the points of contact around the ceiling to the newly constructed frame then an air powered stapler mechanically secured the two halves together. Once completed my bunk roof is now much more sturdy and has lost the bulge that it originally had.

And to wrap this post up - Thanks to all who posted in response to my original inquiry, you sure helped to ease my concerns and answer my questions. I wanted to contribute this write up to the board in case anyone else is considering or wondering about doing this job and what it entails.

Pete