Each coach is crafted using a series of carefully coordinated steps.
By Mark Quasius, F333630
Entegra Coach veers from the standard approach to building motorhomes. Rather than the frequently used vacuum-laminated construction process, the company utilizes what’s known as the hung sidewall method — similar to that employed in the construction of stationary homes — for its Aspire, Anthem, and Cornerstone motorhomes.
Recently I was afforded the opportunity to follow the construction of our Cornerstone motorhome at Entegra’s Middlebury, Indiana, plant as it progressed from a bare chassis to a finished product.
From start to finish, an Entegra motorhome can take up to 12 weeks to build. The majority of the construction occurs during the first several weeks. The next few weeks are spent in paint, while the last week is devoted to final finish and inspection.
Production begins with the chassis — in Entegra’s case, a Spartan. When a bare chassis arrives, it is sent to the weld shop, where employees fabricate the steel subframe structure and weld it onto the frame. At this time, they add the bulkhead, mount the leveling jacks, and install the various subassemblies, such as generator slide rails. The finished chassis structure is painted and undercoated to prevent rust.
Next, the chassis moves to Entegra’s main assembly area, which is housed in a 188,000-square-foot, state-of-the-art building that opened in June 2015. In fact, our 2016 Cornerstone was one of the first Cornerstones to be built at the new facility, where production is divided into a series of stations.
The chassis proceeds to the first station. The pump for the hydraulic leveling jacks is installed, along with an automatic priming system to cycle the jacks and purge air from the system. A steel roll bar hoop is added over the cockpit area for additional chassis rigidity and passenger protection. The generator is hoisted into the chassis, and the batteries and major wiring harnesses are installed.
The chassis is placed onto pneumatic hover pads, where a tracked roller system allows the coach to be moved sideways as it progresses down the line.
A pair of Magnum inverters are installed between the frame rails, so as to minimize the amount of cargo space they take up.
At the next station, the plywood basement floor and partition walls are installed and carpeted. Basement cargo trays and the fresh water and holding tanks are put into place. Additional wiring is run, and various pneumatic and electrical accessories are mounted to the fire-wall bulkhead.
The automatic transfer switch and Aqua-Hot hydronic heating system are installed at the subsequent station. Larger items, such as the Sani-Con Turbo macerator, water pump, and other plumbing components are installed there also. The dash heat and Aqua-Hot heat exchanger are mounted in the cockpit area. This is also when the insulation process begins. Any open structural tubing ends are filled with foam to prevent harmonics, and insulation is placed in the cockpit seat pedestals and numerous other areas.
While these tasks are being performed, the floor is being built in an adjacent area. First, 2x4s are positioned in a template pattern on a large table and then fastened together. A hydronic heating loop is woven into the floor, a component of the in-floor heating. Next, 3/4-inch marine-grade plywood is glued and screwed to the 2×4 framework. Additional cleats are applied over every plywood joint to prevent squeaks from occurring later. Reflective Flexfoil insulation is added to direct the heat from the hydronic loop up into the tile. Acoustic-quality fiberglass batt insulation is added next, followed by more plywood and a Tyvek membrane; this creates a floor with an R-33 insulation value. Reflective foil insulation panels and foil tape are placed where the rear engine compartment will be.
At the same time, the 2 1/2-inch-thick sidewalls are being built. Plywood is applied to all interior walls, which are then covered with reflective Flexfoil insulation material. Window and door penetrations are cut out. The walls are stacked, ready to be joined with the chassis.
The chassis is moved to the next bay, where the finished floor assembly is hoisted onto it and secured.
Cabinets are built in the cabinet shop, up on the mezzanine. When a motorhome’s cabinets are completed, they are placed into a large cradle and hoisted down onto the coach floor, and then secured. Vinyl floor covering is installed in every location that is not carpeted or tiled, including cabinet interiors.
The coach is now moved to the next station, where the PEX plumbing lines are installed. At this point, the sidewall assemblies are hoisted over and set on the motorhome floor. Each sidewall is fastened to the floor from the top. Entegra workers drill through the floor and sidewall base plate and bolt them into place. Once the walls are secured, the exterior walls of the slideouts are cut out and sent off to the slideout area, where the rest of the slideout is built, wired, and equipped with cabinets.
The motorhome is moved to the tile area, where porcelain tile and an inlaid mosaic tile centerpiece are installed on the floor. Entegra workers hand-cut each tile to butt up against the cabinetry, rather than run beneath it. This helps to prevent squeaks; makes cabinet installation more secure; and allows for easier replacement should a tile become damaged. The shower walls and entry steps are also hand-tiled.
Once the grout dries, additional work ensues, such as finishing the utility bay and installing the shower stall enclosure, the toilets, and overhead cabinets in the cockpit.
While this is happening, the ceiling is being built in a side area. The interior panels are laid out on another template table, and openings are made for lights and HVAC components. The aluminum roof trusses are then attached to the roof panels with adhesive. These panels are placed in a cradle and hoisted to the top of the coach, where they are installed and fastened to the sidewalls.
At the next station, electrical wiring looms are run through the roof and dropped into various locations. Insulated ductwork is installed for the rooftop air conditioners. Fiberglass batt insulation and a layer of reflective foil insulation are applied next. The 3/8-inch plywood roof decking is screwed down to the roof trusses, while other crews insulate the sidewalls with more fiberglass batt insulation. Electrical accessories and lighting are added at the same time and connected to the wiring looms.
Once the coach walls are insulated, the fiberglass sidewall material can be hung. A strong, high-tech adhesive is applied to the studs and framework, and the massive fiberglass sheet is lifted into position. Screws and large clamp frames apply adequate pressure while the fast-drying adhesive cures.
Once the frames are removed, the front and rear caps are installed. The front cap comes with the windshield preinstalled; the rear cap already contains a mechanism for the power tailgate lift. Everything is trimmed and fastened in place.
Next, the completed slideout assemblies are lifted into place. Wiring is connected, and the slideouts are bolted to the heavy-duty rack-and-pinion slideout mechanisms. The fiberglass roof is fastened to the exterior plywood roof with adhesive, and various moldings and trim are applied. Basement cargo bay doors, fender panels, the radiator grille, and windows are installed. Once the slideouts are tested and wired, fiberglass is applied to the outside; it is fastened and clamped in the same manner as the main sidewalls.
Interior work begins in earnest. This includes installation of the bed and other furniture, mirrored ceiling treatments, interior lighting, the entertainment system, cabinet and wardrobe doors, even the bedroom ceiling fan.
The motorhome is placed over a pit and undercoated. Next, it goes to the paint shop for three painstaking weeks.
Paint shop staff inspect the fiberglass for defects, repairing any imperfections if necessary, and fine-sanding the surface to achieve a smooth-as-glass finish. Window glass, the engine compartment, and other areas are masked off to prevent overspray from the Sikkens show-caliber paint. The four-color paint scheme is applied in layers. First are fine detail portions, including a graphic template or screen. They are masked off, and the next most dominant color is applied. The process continues until each color has been sprayed.
Once the masking templates are removed, workers carefully trim any paint lines, ensuring that no ridges exist in preparation for the polyurethane clearcoat. Three coats of clearcoat are applied; sanded and buffed smooth; and followed with two more coats. More cutting and buffing ensue, resulting in a smooth, glossy finish.
Entegra officials place great emphasis on quality control. Each motorhome is continually inspected as it travels through the production line, and any shortages or issues are noted along the way. When the coach reaches the final-fit-and-finish area, any missing furniture, fixtures, or items that were overlooked earlier are added, and inspections continue.
The coach is moved to a bay for installation of the awnings, exterior lighting, mirrors, trim, and other accessories. The fully completed coach then goes to a state-of-the-art bay where ride height and alignment are checked.
The completed coach undergoes one final inspection. The inspection crew — a separate entity from the production department — determines when the unit is ready to ship. Their only goal is to ensure that the customer will enjoy a trouble-free motorhome.
Entegra Coach, P.O. Box 460, Middlebury, IN 46540; (800) 517-9137; www.entegracoach.com