Enclosing the underbelly: a few design questions
We want to do some winter traveling next year - time to enclose the underbelly. We will need to stay at RV parks in order to power the heat tape -- boondocking in very cold weather is just not going to work for us. (Sigh.) The biggest downside of enclosing the underbelly is that no matter how well I seal it, it will provide a home for critters. That is a risk that can't be avoided. (Fortunately, the trailer itself is now well sealed. No more mice in the last several years of camping!)
After doing quite a bit of research, I've decided to use rigid foam panels with a coroplast coating. I have plenty of room under the trailer (since it is lifted due to an axle flip), even though the tanks hang down a few inches below the level of the frame members. The enclosure will essentially be an upside-down box, with side pieces that drop down a little so as to clear the bottom of the tanks. The sheet of insulating foam (and the coroplast bottom layer) will rest on cross-members.
Here is a rough sketch showing the general layout:
But there are a few specific issues:
First, what is the best way to secure the vertical panels of the enclosure to the existing chassis frame members? Drill into the steel frame members and attach brackets, using self-tapping sheet metal screws? Or weld drop-down brackets to the frame and then attach the enclosure to those brackets? (My son knows how to weld - I don't.) My concern about drilling into the frame is that I do not want to weaken it at all. My concern about welding is that he will have to weld upside-down, under the trailer -- it seems risky.
Second, there will be a 90 degree joint between the vertical drop-down sides of the enclosure and the horizontal bottom panel. What is the best way to seal that joint? (Not duct tape. It does not hold up well when pelted with rainwater at 60 mph. Don't ask how I know this.)
Third, is it better to use aluminum or steel for the cross-members supporting the bottom foam panel? Aluminum is light and easy to work with. Steel is stronger but heavy. The aluminum might sag. The steel might put too much stress on the attachment points of the enclosure.
Fourth, is it necessary to glue the coroplast to the foam panels? If so, how? My inclination is to use 3M industrial-strength aerosol contact cement. It's expensive, but it works. I would do the gluing before installing the foam.
As always, your advice is greatly appreciated!
After doing quite a bit of research, I've decided to use rigid foam panels with a coroplast coating. I have plenty of room under the trailer (since it is lifted due to an axle flip), even though the tanks hang down a few inches below the level of the frame members. The enclosure will essentially be an upside-down box, with side pieces that drop down a little so as to clear the bottom of the tanks. The sheet of insulating foam (and the coroplast bottom layer) will rest on cross-members.
Here is a rough sketch showing the general layout:
But there are a few specific issues:
First, what is the best way to secure the vertical panels of the enclosure to the existing chassis frame members? Drill into the steel frame members and attach brackets, using self-tapping sheet metal screws? Or weld drop-down brackets to the frame and then attach the enclosure to those brackets? (My son knows how to weld - I don't.) My concern about drilling into the frame is that I do not want to weaken it at all. My concern about welding is that he will have to weld upside-down, under the trailer -- it seems risky.
Second, there will be a 90 degree joint between the vertical drop-down sides of the enclosure and the horizontal bottom panel. What is the best way to seal that joint? (Not duct tape. It does not hold up well when pelted with rainwater at 60 mph. Don't ask how I know this.)
Third, is it better to use aluminum or steel for the cross-members supporting the bottom foam panel? Aluminum is light and easy to work with. Steel is stronger but heavy. The aluminum might sag. The steel might put too much stress on the attachment points of the enclosure.
Fourth, is it necessary to glue the coroplast to the foam panels? If so, how? My inclination is to use 3M industrial-strength aerosol contact cement. It's expensive, but it works. I would do the gluing before installing the foam.
As always, your advice is greatly appreciated!
