Slide-outs, colloquially called bump-outs and glide-outs, are moving room sections which extend the living space of recreational vehicles, or RVs, when deployed. Conventionally fitted into the side walls, slide-outs have become increasingly available in front- and rear-end configurations. Typically up to 12-feet long and three feet in depth, four slide-outs can effectively double the usable footprint of an RV. Among new RVs manufactured in 2010, 70 per cent had at least a single slide-out, and an industry has developed around retrofitting RVs that were originally manufactured without them. Slide-out conversion is a massive undertaking, requiring advanced skills in engineering design, welding and fabrication, carpentry, plumbing and electrical installation.
Engineer the project so your RV is not structurally weakened. Plan to weld support beams and new hoops to strengthen the structure of the vehicle. Decide how you will insulate the slide-out walls, and how you will seal the "joins" so heated or cooled air cannot escape, and moisture cannot enter. Decide how many windows will need, how will they be installed, and how they will be sealed.
Determine whether the slide-out will accommodate free-standing furniture only, or if power to sockets and lighting will be needed. Will you install wiring to entertainment system speakers, or even travel plumbing, waste pipes, and propane lines for a kitchen? If the slide-out includes a bed, ensure sufficient room exists for it to move into the room when the slide-out retracts.
Buy motors or gearing mechanisms equipped with positive locks, so that when the slide-out deploys, it cannot drift and thus relax the watertight seals. Pick a drive system that allows fine adjustments, so that a watertight seal can be obtained and maintained. Will you install a manually-operated rocker switch to control movement of the slide-out, or drive electronics that sense when the slide-out has sealed, and automatically switch off?
Decide between a rack/gearing system, or an hydraulic drive assembly. If you choose an hydraulic system, there is another choice between two or four drive cylinders. Where will you locate the device which equalises pressure between all the cylinders, so it appears innocuous but remains accessible? Determine whether you will mount the actuation system above the main RV floor, or beneath the floor with through-frame connectors, and whether the actuator system will need to be welded to the chassis. How will you accommodate the upper and lower mechanisms, and then disguise them so their presence is invisible, both when the slide-out deploys and retracts?
Choose between a floor-mounted glide system, and one mounted to the sides, comparable to a large kitchen drawer. Will you be satisfied with a small upward step into the slide-out, or will you need a ramp system that allows the deployed floor to be at the same level as the main floor in the vehicle? For the latter, special mechanisms, drives and seals must be fabricated.
Take out your furniture and store it where it will not cause inconvenience during the project. Strip out any wiring harnesses in the wall and floor, and reroute plumbing runs. Drop any underbody components, such as fuel tanks and holding tanks, that will obstruct access to the project, and move them so the new equipment can be installed in their place. Remove the pre-existing wall, preserving the panel if it can be reused as the outside wall of your slide-out.
Reinforce the hole with metal tubing, trading off weight with structural integrity. Create a slide-out box from metal tubing, and skin it with a composite manufactured for RV walls. Seal all the corners and joints. Install a drive system and fit the box to it, then fit seals, trim, and an awning.
No investment made in this project can be recovered in the resale of your RV. A do-it-yourself alteration of such magnitude may lessen the value of your vehicle.