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Build steps: C — Bath 18

Build in this order. Each gate catches work that becomes hard to reach later.

Read this first

Road / curb side

Road is the driver’s side. Curb is the passenger side and has the door.

VHB

Very high bond tape. It holds the aluminum skin after it touches, so dry-fit first.

12 V / 120 V

12-volt direct current runs battery loads. 120-volt alternating current comes from the campground inlet.

GVWR

Gross vehicle weight rating is the most the loaded trailer may weigh. Design C is 5,000 lb.

0. Plan, buy, and learn to weld 2–5 days

Goal: Have every actual opening and major part in hand before cutting its structure.

What you do

1. Read the design drawings and mark the 216 by 96 in box, 60 in tongue, and 115 in axle position.
2. Buy or reserve the door, four windows, roof fan, A/C, furnace, water heater, tanks, axle, wheels, and coupler.
3. Set up a flat welding area, fire extinguisher, welding helmet, gloves, grinder guard, clamps, tape, square, and level.
4. Practice cutting, tack welding, and welding scrap of the same steel thickness. Cut a practice weld apart and ask an experienced welder to inspect it.
5. Make a full-size opening list from the real product manuals. Do not frame from a listing photo.

You need: tools list for the welder, grinder, square, level, jack stands, drill, saw, and safety gear; materials list for the selected parts and steel.

Check before the next phase: Design C is the working drawing; axle center is 115 in back from the box front; every purchased opening has a maker cutout; an experienced welder is booked for phase 1.

Joe’s videos: Part 1; Part 3.

Safety: Welding and grinding make fumes, sparks, and fire risk; use ventilation, eye protection, and a fire watch. OSHA

1. Frame 3–5 days · helper + experienced welder

Goal: Make a level, square steel foundation without loading it.

What you do

1. Put the work on jack stands and level the work surface.
2. Cut two 216 in 2 by 4 by 3/16 in main rails, end rails, and 2 by 2 by 11-gauge crossmembers at 24 in spacing.
3. Tack the rectangle. Measure both corner-to-corner diagonals before final welding.
4. Fit the 60 in, 2 by 4 by 3/16 in A-frame tongue, coupler plate, and jack plate.
5. Let an experienced welder complete and inspect structural welds in short, alternating runs.

You need: tools list for jack stands, level, framing square, clamps, welder, and grinder; materials list for frame steel, coupler, jack, chains, and plates.

Check before the next phase: Box outside is 216 by 96 in; both diagonals are equal; rails are level; crossmembers are 24 in on center; tongue is centered; do not weigh it yet.

Joe’s videos: Part 1 — frame; Part 7 — coupler.

Safety: Keep the trailer supported on rated stands, never a jack alone. Welding fumes and hot steel need the phase-0 controls.

2. Running gear 2–3 days · helper + experienced welder

Goal: Put the trailer safely on its single braked axle for its first roll test.

What you do

1. Measure 115 in from the box front and mark the axle centerline on both rails.
2. Have the experienced welder locate and weld the spring hangers at that line.
3. Install the 5,200 lb electric-brake axle, springs, hubs, ST225/75R15 load-range-D wheels, and fenders.
4. Route protected brake wires and install the breakaway switch and its battery.
5. Roll it slowly on level ground and listen for rubbing or binding.

You need: tools list for floor jack, stands, torque wrench, crimper, and drill; materials list for axle, brakes, wheels, tires, fenders, and breakaway kit.

Check before the next phase: Both hanger marks are 115 in from the box front; tires clear the frame and fenders through suspension travel; brakes actuate with the breakaway switch; use the wheel maker’s lug-nut torque, because no source for this exact wheel was found.

Joe’s videos: Part 1; Part 2 — wheel wells; Part 7.

Safety: Chock wheels before working. Electric brakes and the breakaway system are part of the 5,000 lb design; Texas requires brakes above 4,500 lb. source

3. Floor 3–4 days · helper

Goal: Close the floor only after the under-floor tank work is reachable and tested.

What you do

1. Fit wood floor joists above the steel, leaving drainage space at steel as Joe did.
2. Build tank hangers for the 18 gal black, 30 gal grey, and 30 gal fresh tanks.
3. Install all three tanks before the floor closes. Run tank drains and the 3 in dump outlet now.
4. Fit rigid foam between joists and fasten 3/4 in plywood floor.
5. Seal the underside after all hangers and plumbing penetrations are complete.

You need: tools list for saw, drill/driver, clamps, and sealant gun; materials list for joists, foam, plywood, tanks, straps, drains, and underside seal.

Check before the next phase: All three tank hangers carry the tanks, not plumbing; black tank is below the toilet location; dump outlet is reachable; floor is flat; no under-floor fitting is trapped without service access.

Joe’s videos: Part 1; Part 2; Part 9 — sink.

4. Wall and roof framing 4–6 days · helper + experienced welder

Goal: Build the straight, angled-front steel shell around real openings.

What you do

1. Tack 1 by 1 by 16-gauge wall and roof tube to the 76 in inside-height plan.
2. Make the front angle 12 in run by 16 in drop. Keep the rear square.
3. Frame the curb door at 26 by 72 in and the road, curb, rear, and front windows at 30 by 20, 30 by 20, 40 by 18, and 26 by 16 in.
4. Frame the 14 by 14 in bath fan and 14.25 by 14.25 in A/C roof holes from their real manuals.
5. Weld in wood blocking at every opening, as Joe did, before insulation.

You need: tools list for welder, clamps, square, level, drill, and saw; materials list for 1 by 1 tube, blocking, and the actual doors, windows, fan, and A/C.

Check before the next phase: Shell is square and plumb; front angle is 12 by 16 in; every opening matches the real unit’s required opening; 76 in inside height and 3 in roof thickness remain available.

Joe’s videos: Part 1; Part 3.

Safety: An experienced welder checks thin-tube heat distortion and structural attachment to the frame.

5. Rough-in 4–6 days · helper for roof work

Goal: Put hidden water, gas, and electrical routes in before panels hide them.

What you do

1. Run cold and hot water, sink/shower drains, black vent, and accessible low-point drains.
2. Install the propane line from two 20 lb cylinders and the two-stage regulator to furnace, heater, and exterior quick-connect.
3. Run labeled 12 V and 120 V routes in separate protected paths.
4. Set the furnace and water-heater openings, roof vent openings, and A/C opening from the maker manuals.
5. Photograph every route and label each end before insulation.

You need: tools list for tubing cutter, crimper, multimeter, fish tape, and leak-test equipment; materials list for PEX, drains, propane line, wire, conduit, and appliance fittings.

Check before the next phase: Water and drain routes reach the 30 gal fresh, 30 gal grey, and 18 gal black tanks; wires are protected from metal edges; propane line is leak-tested before coverage; each circuit and pipe is labeled.

Joe’s videos: Part 9; Part 10 — 12 V; Part 11 — roof wiring.

Safety: Test propane with an approved leak-test method, never a flame. Follow every appliance installation manual; its cutout and vent dimensions are not interchangeable.

6. Insulation and interior panels 3–5 days · helper

Goal: Insulate the shell while keeping every service point reachable.

What you do

1. Inspect and photograph rough-in one last time.
2. Cut rigid foam around tube, blocking, and wires without crushing pipes.
3. Leave appliance clearances and exterior vent paths exactly as their manuals require.
4. Install 1/4 in luan interior panels, leaving removable access panels at valves, pump, converter, and junctions.
5. Mark hidden framing and routes for later fasteners.

You need: tools list for saw, knife, straightedge, drill, and brad nailer; materials list for foam, luan, trim, fasteners, and access-panel hardware.

Check before the next phase: Insulation does not block roof vents, furnace, or water-heater paths; every shutoff, fuse, and drain stays reachable; panels are dry and firmly attached.

Joe’s videos: Part 3; Part 4.

7. Skin 3–5 days · helper

Goal: Bond a weather shell before installing exterior hardware.

What you do

1. Dry-fit every .030 aluminum panel and opening before exposing VHB liner.
2. Clean the approved bonding surfaces and apply VHB tape as Joe did.
3. Bond wall panels first, then the roof panel and roof seams, following Joe’s sequence.
4. Use butyl tape at hardware seams and compatible lap sealant at roof seams and penetrations.
5. Trim edges only after the panels are fully supported.

You need: tools list for scaffolding or ladders, rollers, clamps, snips, and sealant gun; materials list for aluminum, VHB, butyl, lap sealant, trim, and fasteners.

Check before the next phase: No VHB panel was committed before its fit check; all roof seams are continuous; skin is flat around every framed opening; sealant has no uncovered gap.

Joe’s videos: Part 2 — aluminum exterior; Part 3 — trim.

Safety: Panels are sharp and awkward. A helper supports each sheet; do not work on a wet roof.

8. Openings 2–3 days · helper

Goal: Make every hole weather-tight before finish work.

What you do

1. Install the 26 by 72 in door and four windows on their butyl bedding.
2. Install the bath roof fan, 13,500 BTU A/C, furnace exterior door, and water-heater exterior door.
3. Use the fasteners, flanges, clearances, and sealant specified by each maker.
4. Close and latch each opening. Then run a gentle hose test from low to high.

You need: tools list for drill, drivers, ladder, hose, and sealant gun; materials list for the openings, butyl, lap sealant, screws, and trim.

Check before the next phase: Door latches; windows open and lock; fan and A/C flanges are sealed; hose test finds no water inside; exterior appliance doors clear their required vents.

Joe’s videos: Part 3; Extra — fan.

9. Wet bath 3–5 days

Goal: Finish a washable 42 by 42 in bath that drains and vents correctly.

What you do

1. Set and support the shower pan in the front road-side bath zone.
2. Install FRP (fiberglass-reinforced plastic) wall panels and seal every edge.
3. Set the gravity toilet on the black-tank flange and connect its roof vent.
4. Install the shower valve, head, drain, and bath vent fan.
5. Fill and drain the shower pan before closing trim.

You need: tools list for drill, hole saw, tubing tools, caulk gun, and level; materials list for pan, FRP, toilet, flange, valve, drain, vent, and sealant.

Check before the next phase: Toilet flange is secure over the 18 gal black tank; shower drains to the 30 gal grey tank; black vent reaches the roof; pan holds water without a leak; every FRP edge is sealed.

Joe’s videos: Part 12 — bathroom cabinet; Extra — shower.

10. Cabinets, desk, bench, wardrobe, and bed base 5–8 days · helper for bed

Goal: Build the interior furniture around the systems rather than through them.

What you do

1. Build the galley over the 46 by 22 in zone and keep the fridge and sink plumbing accessible.
2. Build the 56 by 28 in desk for two 27 in monitors.
3. Build the 31.5 by 24 in counter over the fresh tank, with pump access.
4. Build the 39.5 by 22 in bench over battery and electrical access, then the 24 by 22 in wardrobe.
5. Build the rear 60 by 80 in queen-bed base and the 60 by 11 in shelf.

You need: tools list for saw, drill/driver, pocket-hole jig, clamps, sander, and brad nailer; materials list for plywood, lumber, fasteners, hinges, slides, finish, and flooring.

Check before the next phase: Every cabinet is fastened to structure; tank, pump, battery, fuse block, and valves remain serviceable; bed is 60 by 80 in; desk has its full 56 by 28 in clear top.

Joe’s videos: Part 4; Part 5; Part 6; Part 9.

11. Appliances and systems final 4–6 days

Goal: Make every utility work alone before relying on it in camp.

What you do

1. Mount the converter/charger, breaker panel, 12 V fuse block, 100 Ah LiFePO4 battery, lights, outlets, and pump.
2. Finish the water heater, furnace, A/C, fridge, alarms, and all labeled connections.
3. Install the battery main fuse close to the positive terminal.
4. Test every 12 V and 120 V circuit one at a time.
5. Fill tanks and test every water and drain joint. Run the furnace and water heater outside first.

You need: tools list for multimeter, crimpers, torque screwdriver, and leak-test tools; materials list for converter, panels, battery, fuse block, wire, lights, outlets, pump, appliances, and alarms.

Check before the next phase: Every circuit is labeled and works; main battery fuse is installed; propane system is leak-tested; full tanks show no leak; CO, propane, and smoke alarms test; furnace and heater exhaust outdoors.

Joe’s videos: Part 9; Part 10; Part 11.

Safety: A battery main fuse protects the cable from fire. Select its rating and cable from the load and cable length, not a copied guess. source

12. Lights, brakes, and road test 2–3 days · helper

Goal: Prove the road systems at low speed before a trip.

What you do

1. Wire the 7-pin connector, tail/stop/turn lamps, plate lamp, side markers, reflectors, and clearance lamps.
2. Connect the brake controller and test both electric brakes and the breakaway switch.
3. Measure tongue weight with a rated scale or bathroom-scale lever setup.
4. Confirm loaded tongue weight is 10–15% of loaded trailer weight.
5. Make a short, slow tow on local roads. Recheck wheel fasteners to the wheel maker’s torque instruction.

You need: tools list for multimeter, crimpers, scale or lever materials, and torque wrench; materials list for 7-pin cable, breakaway kit, brake controller, DOT lamps, clearance lamps, and reflectors.

Check before the next phase: All seven-pin functions work; brakes respond to controller and breakaway test; 96 in width has clearance lamps; tongue is 10–15% loaded; short tow has no sway, heat, rub, or leak.

Joe’s videos: Part 7; Part 8; First trip.

13. Weigh, title, and plates 1–2 days

Goal: Finish the Texas paperwork with the trailer as built.

What you do

1. Take the completed trailer for a certified weight certificate.
2. Keep receipts and photos for steel, axle, coupler, lights, and major parts.
3. Get the VIN and TxDMV Regional Service Center eligibility process started.
4. Take the eligibility letter, certificate, photos, receipts, Form VTR-141, and Form 130-U to the county tax assessor-collector.

You need: tools list for a document folder and camera; materials list receipts; Texas registration guide for the forms and process.

Check before the next phase: Certified weight certificate is in the file; VIN paperwork is complete; Form VTR-141 and Form 130-U are complete; title and plate are issued before normal road use.

Joe’s videos: First trip; Simple camping.

Time and cost-group map