Should I cut a hole in the RV slide?

The Alliance Paradigm fifth wheel features a pull-out storage compartment hidden behind the fireplace, providing convenient and discreet storage space. This innovative design allows owners to maximize space utilization while maintaining a clean and stylish living area. The storage compartment is designed for smooth operation, with a simple mechanism for opening and closing. Unfortunately, the Avenue model (which we have) doesn't have this feature despite a large empty space behind the heater. I discovered this space in our fifth wheel after removing the heater to access the wiring when upgrading our CD/radio. The problem was how to access this area in our rig without the drawer feature of the Paradigm.

I started researching the possibility of adding a storage door to the outside of the trailer slide in order to access the space opposite the fireplace appliance. YouTube has been a great resource for many of the modifications I have made in the past, so it was the first place I turned to for information. After viewing a couple of videos it appeared to be a do-able project. My first step was to remove the fireplace appliance and move the electrical outlet mounted on the back wall to a more favorable location. A large wiring bundle for the TV, radio and speakers comes into that space and needed to be moved. I zip tied the loose wires and mounted the outlet to the shelf bottom above the fireplace appliance.

The next step was a bit tricky. How far above the compartment floor would be the best place to cut the hole in the slide? After taking some measurements on the inside and outside of the space I determined the best location and door size. I wanted to be conservative with the size and opted for a 12 inch by 36 inch horizontal storage door which I ordered from Amazon.

When the door arrived last week I inspected it and used the shipping container to cut out a cardboard template of the door. I marked the middle of the template and attached it to the inside of the fireplace slide wall compartment. This allowed me an opportunity to double check the location on either side of the future door opening. At this point I'm trying to think of what else I need to do before cutting through the trailer wall. I know that once I cut through that wall, I've "crossed the Rubicon".

My first thought was to drill a small hole through the inside wall in the center of the mounted template. Once that was done I took the template to the outside and aligned it with the hole to level and mark the exterior wall for cutting. Everything looked good so I started cutting through the fiberglass siding with my Dewalt oscillating saw. No turning back now!

The key to the process was moving slowly and letting the saw do the work through the exterior fiberglass, foam insulation layer and thin interior plywood backing. With the cutting completed I removed the cut out and clean up the edges for a test fit of the new storage door assembly. Voilà, a near perfect fit!

Just a little more finish work needed to add some wood framing between the fiberglass and plywood to hold the door frame in with screws, some butyl tape to hold the insulation, and silicon caulk around the exterior edges. Mission accomplished!

The new storage space will now hold all our E-bike accessories which we used to keep in the back seat of the truck in a large plastic box We now have an empty back seat! There's even room for our fishing gear in our new compartment..