Building Your Own RV

Building your own RV is certainly not for everyone.  It takes a lot of planning, time, and money.   Why would anyone want to go to all the trouble to build their own RV?   Some people will opt to build their own in an attempt to save money.   Sometimes that works, but unexpected expenses can drive the price up rather quickly.  Most people have no idea what is involved and get some rather unpleasant surprises as they proceed.   Some people may want to build their own RV to implement specific features into the design to meet their needs.  Someone who is extra tall may need higher than standard ceilings, raised countertops, and a longer bed than is available in production models.  You may have a hobby that requires special work space or storage.  Do as much research and planning as you can before you begin.  Small motorhomes can be built into a conventional van.   Larger models will need a bigger truck or bus as a starting point.  No doubt you have seen converted school buses on the road.  Home-made conversions can be ugly or interesting, depending on how skilled the craftsman is and how much he is willing to invest in cosmetics.  I've seen some very "interesting" adaptations, like a VW van given an expanded roof by the addition of a VW beetle body welded to the top.  Sure looked strange!  Other variations include wooden shack like structures on a pickup or heavy duty truck that look like they belong on an Ozark mountaintop instead of the highway.  I've seen photos of a very sleek custom made aluminum "Starstreak" motorhome built on a 1976 Cadillac El Dorado chassis.  This vehicle now lives in the RV Hall of Fame in Elkhart, Indiana.  Be sure to watch the slide show for their Featured Units.  Many of you probably recall the multi-colored school bus used by The Partridge Family on the TV show of the same name.  It was colorful and functional but not what you would call beautiful.

If you have the budget for it, you can, of course, have an RV custom built to your specifications.  Newell and Foretravel both specialize in building customer coaches to spec and many other major manufacturers will work with you to adapt their high end products to meet your needs.  Unfortunately, these units often cost over $1,000,000!

Before attempting to build your own RV consider whether there is already something out there that will meet your needs. There are many different styles of RVs in existence and it may be a lot faster and even cheaper to buy one than to build your own.  Used RVs can often be had for very little money.  You may be able to adapt a factory model to your personal needs fairly easily.  But, if you are determined to build your own, read on!

I have never built my own RV but I did build (or more accurately adapt) my own motorcycle trailer, which has many RV like components.  I purchased a custom made motorcycle trailer from an engineer who had built it for his own use and no longer needed it.  One of the things I really liked was it was built on a 5500# single axle (most single axles trailers are only 3500#).   I also appreciated the sturdy steel frame construction that made it suitable for off road trips. It came with a rear ramp door, counter across the inside of the front over a nice Kennedy tool box.   I added peg board, additional lights and wiring, a water tank, pump, and sink, and eventually even a roof A/C.  I put in shelves and closet rods to store riding gear, a rack for tie downs, and racks to secure my gas cans.  When it was done it was almost a motorcycle shop on wheels!  Building it was almost as much fun as using it and I got a lot of nice compliments from my fellow riders.  Having appropriate tools, equipment, and spare parts on board allowed me to lend assistance to many of my riding companions over the years.

One way to minimize engineering (and cost) is to customize an existing RV to your individual specifications.   Many times it is easier and cheaper to modify an existing unit than to start from scratch.  You may be able to take advantage of fresh water, waste water, propane and electrical systems without having to design and engineer them yourself. 

Your first step is to determine what kind of RV you want to build:   motorhome, truck camper, or trailer. One of the most popular home-made units is the tear drop trailer.   They can be built from scratch and plans are available on the Internet.  In this case you buy an axle and build your own chassis from the ground up.   The next most common conversion is creating a motorhome from an old bus.  I've seen converted school buses, city buses, and Greyhound buses.  Greyhounds or other inter-city buses make the best platforms.   City buses are often geared for lots of stop and go driving which is not always the best configuration for a motorhome you want to go places in but I have seen successful conversions done on old city buses.   Don't know how long they lasted or what kind of gas mileage they got, but they were well built and very functional.  School buses are probably easier to come by, less expensive, and should be an acceptable platform if they've been well maintained.  As mentioned above, you might remember the multi-colored bus on the old TV show "The Partridge Family".   The presence of an existing bathroom on inter-city buses sometimes saves the builder some time and money -- if you're OK with the location of the existing restroom.   If not, it may be an added expense and construction problem to relocate it.   If you don't need lots of room, you might start with a standard cargo or passenger van.  One advantage of using a van, is they usually will fit in your garage.  The venerable Chevy Stepvan is another fairly popular choice with do it yourself motorhome builders.  Its open, boxy shape allows lots of interior design flexibility and stand up head room.   If you want to build a truck camper you're going to most likely have to build it from scratch and you'll need some good plans to ensure structural integrity.  My first motorized camping vehicle was a 1951 Chevy Suburban with minimal modifications.  I added curtains for privacy.  Sleeping bags rolled out on 1/2" foam pads in the back of the vehicle provided beds.  A folding TV tray, a plastic dishpan, and 3-gallon plastic water jug served as both kitchen sink and hand washing basin.  A large Coleman cooler substituted for a fridge.  Eventually we even added a porta-potty.  It wasn't fancy but it sure beat trying to set up a tent in the dark or the wind!  And it wasn't very expensive at all.  Even driving it was fairly cheap.   It had the original Chevy 6 cylinder engine and a manual transmission and, of course, ran on the lowest priced regular gasoline.  As rudimentary as it was, it was a lot warmer and more comfortable and convenient than camping in a tent.  And it didn't require any structural modifications.

Planning is one of the most critical steps. Y ou will want to list all the features you want to have and try out several floor plans. Keep in mind your floor plan may affect what kind of vehicle you choose for the platform and, in turn, what vehicle you get may affect your floor plan.  Allow some flexibility or be willing to make adjustments based on features and limitations of your platform. Some of the basic considerations should include:  how and where you intend to use the completed unit, how many people will be traveling in it, and the ages of the travelers (accommodations for kids may be different than those needed for adults).  If anyone in your family has any disabilities you may need to include accommodations in your design for their special needs.  Your design might also be influenced by any equipment or appliances you may already have.   A fairly good cost-saving way of getting much of what you need for a conversion is to buy a cheap used or salvage travel trailer and use it as a donor for cabinets, appliances, holding tanks, and furniture.

Weight is always a major concern for an RV.   RVs are usually framed with 2x2s, not 2x4s or 2x6s like houses.  Using 2x2s gives you about 4" additional interior space and about half the weight as 2x4s, both significant advantages for an RV.  I've seen an RV built like a house, using 2x4 framing and then using 1/2" sheetrock for interior walls.  Wow!  Was that thing heavy!   It will certainly be sturdy, but I wouldn't want to drive or tow something like very far or very often.  Might be OK for a "tiny house" used for a permanent residence that usually doesn't go anywhere.

Choosing the basic vehicle for your conversion is one of the most important steps.  Price is probably a major factor.  Otherwise you could just have million dollar custom Newell or Foretravel built to your specifications.  You will also want to consider the condition and the brand and model of major components, like the engine and transmission.  Seek vehicles with a drive train for which parts are still readily available.  You shouldn't have any trouble finding parts and service for those with Caterpillar or Cummins power plants and Allison transmissions or for GM, Ford, and Dodge trucks. Greyhound buses usually already have an existing bathroom so that may be an advantage -- IF you are willing to have the bathroom where it already is.   If you have designed your own floor plan with a bathroom somewhere else, already having one won't help and may even make things more difficult. While buses are most frequently chosen as the platforms for home-made motorhomes, other trucks are sometimes used too.  The venerable Chevy "Step Van" provides a sturdy option for smaller motorhomes and may be less expensive than a bus.  You can also be assured that mechanical parts will be available.

Major interior components include cabinets, appliances, plumbing fixtures and furniture.  You might be able to adapt cabinets from a donor vehicle or buy new ones at a home center.   Cabinets from home centers will probably be larger than would normally be used in an RV so you may have to adapt the cabinets or adjust your floor plan to accommodate them.  Residential sinks and toilets are usually too big and too heavy to use in RVs.   It is nice to have a donor vehicle to supply appliances, furniture, plumbing fixtures, and holding tanks.  Purchasing a donor vehicle before you finalize your design allows you to have exact specifications for the construction of cabinets and the installation of appliances and furniture.  The donor vehicle doesn't have to be the same style as the one you're building.  You can salvage lots of useful components from an old travel trailer to build your own motorhome.

Finishing the interior.   Some buses already have finished interior shell walls.   Retired Greyhounds usually do.  School buses are more likely to have naked walls.  If your platform doesn't have finished exterior walls, frame the interior with 2x2 lumber, add insulation (bats or foam panels) and cover with 3/16" or 1/4" paneling.  You might want to use FRP (Fiber Reinforced Plastic) board in the bathroom and kitchen areas.  It is attractive, easy to install, waterproof, and easy to clean.   Insulating interior partitions between living spaces is optional.  While it may help you to maintain comfortable temperatures in your living space if you are only occupying a single area (like the bedroom at night), the main benefit is probably soundproofing.  Given the low cost and the ease of installing insulation during construction, I would opt to put it everywhere I could.   Use 1/4" luan plywood for interior sheeting.   If you like the wood pattern of your interior panels you need no further interior finish. However, for variety or to satisfy personal decor preferences, you could paint or wallpaper the paneling to suit your needs.   If you plan to paint or wallpaper you'll probably want to use smooth paneling, not the kind that is grooved to look like planks.   Even if the lines aren't stamped or grooved, they may still show through paint.  If they are smooth and only painted on they shouldn't affect wallpaper but they might bleed through paint and then you would have to prime the walls with something like Kilz to cover them up before painting.

Floors in an old Greyhound or school bus can probably just be carpeted over.   If the floor is metal and is all there is between you and the road, you might want to build it up a bit to reduce road noise, heat from the exhaust system and the pavement, and improve overall insulation qualities. Accommodating plumbing within the floor can make your rig more usable in winter weather.  This would be especially true if you also run your heat ducts in the same compartments as your plumbing. How you build up the floor depends on whether you will be using the space for plumbing and duct work.   If you are not running plumbing inside the floor, put a vapor barrier directly on the existing floor.  If you want to insulate the floor, add a framework deep enough to accommodate the amount of insulation you want to use.   Then install marine grade plywood. Typical residential sub-floors use particle board.   Because of the stress and the potential for water getting in the particle board, I don't recommend it for RV use.   If it gets wet, from a plumbing leak or rain intrusion, it will crumble. Once your plywood is installed you can install your chosen flooring (carpet, tile, vinyl, laminate). Flooring in factory built RVs is often installed before any cabinets or furniture but it is up to you whether you want to do it that way or not.  It may be easier to replace or upgrade the flooring later if it is not installed under cabinets and you may save a few square feet of flooring material.  Carpet with thick padding will provide extra insulation for heat, cold, and sound.

Finishing the exterior.   If you're building a Class B motorhome (van conversion) you may not have to make any changes in the exterior, if the existing paint is acceptable.  Some inter-city buses are have aluminum exterior "skin" that looks good without painting.  You may have to remove existing bus line decals or paint and give the rest a really good buffing.  The areas under paint or decals may be shinier than the original exposed surfaces and it may be difficult or impossible to restore full shine to aged surfaces, forcing you to paint the rig to get a satisfactory cosmetic appearance.  You might be able to get creative and cover the areas where the old logos were with new graphics or murals.  School buses can be repainted and in some jurisdictions, MUST be changed from their original yellow/orange color, but even with a snazzy paint job, it will still look like a school bus!   The addition of chrome wheel simulators adds a nice touch to just about any RV.   If you have the budget for it, you might remove the old painted bumpers and grill and have them chromed to help tone down the school bus image.  Upgrading to heavy-duty off-road style bumpers will give your rig a powerful, brutish or military look and personality while adding useful off road protection, but can be quite expensive.

Wiring your home-made RV shouldn't be a big problem for anyone with familiarity with wiring techniques and requirements.  If you aren't comfortable with electrical wiring, enlist the aid of a qualified electrician.  I did all my own wiring on my enclosed motorcycle trailer.  I recommend being generous in your installation of both 120-volt and 12-volt outlets and lights.  It is a lot easier to run wiring during construction than after! Y ou will probably have two wiring systems: 12-volt and 120-volt.  The 12-volt system will power your interior lights and provide places to install 12-volt accessories.  You may also want to run speaker wires for radios and entertainment systems.  Minimum components would include one or more batteries, a converter, and a fuse panel.   I suggest you plan for using 2 6-volt batteries wired in series for your 12-volt system.  6-volt golf cart batteries are stronger, have more power, and last longer than 12-volt RV batteries.  Your converter should include a high power (at least 40 amp) multi-stage battery charger.   You may find cheaper converters without strong battery chargers.  In that case, you might simply add an automatic automotive battery charger.  When doing your own wiring you have the option to run switches to convenient locations. Something that is very handy but few RVs have, is a 3-way switch for the water pump, with one switch on the main control panel and a second switch in the bathroom.   If you have trouble finding 3-way switches you can wire DPDT switches to serve the purpose.  You have to wire them so that in one position the hot wire is connected to the fixture and in the other position the hot wire is connected to the other switch.  When I wired my enclosed motorcycle trailer, I used ordinary 120-volt residential light switches in convenient locations (like just inside the door) instead of puny little 12-volt toggle switches that often have a tendency to get broken off.  I even used standard 3-way 120-volt switches for my outside work lights so I could turn them on and off from a waterproof outside switch.  Your second wiring system is the 120-volt wiring.  You need a shore power cord, or at least a way to plug into shore power.   I copied something I'd seen on older truck campers for the power connection for my motorcycle trailer.  It is called a "motor base" and is essentially a male plug built into a receptacle so you can plug the female end of any heavy duty extension cord into it.  This works OK for low power requirements.   If you plan to have a roof A/C you will need at least a 30-amp circuit to power it, and that takes a stronger connection and a heavier power cord. Your 120-volt shore power should run directly to a set of circuit breakers that protect all the on board circuits.   Roof A/C should have its own circuit.  So should any other high power appliances. Your 12-volt converter should also have its own 120-volt breaker.  The converter converts 120-volt AC power to 12-volt DC power.   If you plan to have a microwave oven, install an outlet inside the cabinet where it will go and put it on its own circuit breaker.  You will want to run outlets to convenient locations throughout your RV. Check with an electrician to decide how many outlets you should put on each circuit.   I like to separate the circuits "geographically" so if something trips a breaker, it will be easy to know where the problem is.   If ALL the outlets are on one circuit, anything could be the culprit.  I would put the street side of each "room" on one circuit and the curb side on the other.  Plus a separate circuit for the kitchen and the bathroom.   That means in a typical RV with a living area and a bedroom, I'd have at least 6 outlet circuits, but that might not be possible on a 30 amp service since each circuit would be at least 15 amps.   Bathroom and kitchen outlets should be GFCI protected.  GFCI protection can be provided via special breakers or outlets.  Regardless of how many outlets or breakers you install, keep track of the total amperage of your appliance to be sure you don't exceed the input capacity for your RV (typically 30 amps, sometimes 50 amps on larger units with multiple air conditioners).  The input power cord should be connected to a main breaker that is rated properly for the power cord.  Take care running all your wiring and avoid anyplace it could be pinched or frayed.  Use grommets to protect wiring passing through metal or through any panels with sharp edges.  You might want to install a few 120-volt lights at various locations inside and outside your RV.   If you do the wiring yourself, I strongly suggest you familiarize yourself with residential wiring codes and make sure you meet all the minimum standards for wire gauge, circuit breakers, etc.   Make sure all connections are tight.  If you are going to have an on board generator, you will need to either install an automatic transfer switch to switch between shore power and generator power or install a receptacle tied to the generator into which you can plug your shore power cord when you want to use the generator. RVs are typically wired with either 30-amp or 50-amp service, with 30-amp being the most common and what you will find at more campgrounds.  Large luxury motorhomes and trailers may have 50-amp service.  What you need is determined by the total electrical load you expect to operate simultaneously.  If you have a 30-amp supply and enough high power appliances to exceed 30 amps, you will need to alternate use of some appliances.   Otherwise you'll blow circuit breakers to perhaps even overheat some wiring and cause a fire.  I've seen people use adapters to connect their 30 or 50 amp motorhomes to an ordinary 15-amp household outlet and run a standard duty extension cord to accommodate long distances -- and I've seen the extension cords melt before tripping a circuit breaker.  You may have to do some math to determine what your load is -- or can be at any one time. Most appliances are rated in watts.   Watts = volts * amps, so to get amps, divide the watts by 120. Thus, a 1200 watt, 120 volt appliance, like an iron or a hair dryer, will draw 10 amps.

Plumbing is a major part of your design and construction process.   Sinks and shower pans designed for residential use probably won't fit in comfortably in an RV so you'll need fixtures designed for RV use.  You need to understand the right slope for proper drainage.  If your RV is going to be used for winter camping, you will want to protect the plumbing from freezing by enclosing holding tanks and heating the compartment containing dump valves.  Drains can be built using ordinary black ABS pipe you would use in a residential application.   Fresh water lines are usually plastic or PEX and may require special crimping tools for making watertight connections.  Most RVs are designed so the toilet empties directly into the top of the black water tank.   If, for any reason, your toilet cannot be placed over the black water tank, you will need to buy a special power flushing toilet.  Grey water from sinks and showers need only have the right slope for proper drainage plus "P" traps and vacuum breakers to control odors.  Sewer lines must also be vented up through the roof. You will need to locate fresh water and waste water holding tanks in appropriate locations.  If you plan to use the RV in freezing weather, all water tanks, both fresh and waste, should be in an enclosed and heated space or equipped with heating pads.  Black water holding tanks normally need to be located directly below the toilet.  Put your dump valves as close to the tanks as you can where you can conveniently reach them and where they will drain the waste tanks completely.

Propane systems are needed for the stove, furnace, hot water heater, and most refrigerators.   The propane tank must be located outside the living space in a well ventilated area.   Motorhomes should have permanent propane tanks.  Trailers usually have removable tanks.  You will need to consider the location of your tank and the location of your appliances and plan proper routing of gas lines to supply fuel to each appliance.  Trailer tanks are usually mounted on the trailer tongue.   If you are building an RV that will ONLY be used in full-hook up campgrounds you might be able to get by with all electric appliances.   They could even be used for short periods with power from an on board generator, but you wouldn't want to count on using a generator to provide electricity for heating your RV at night.  Running your generator at night is prohibited in most campgrounds, is inconsiderate to fellow campers in primitive camp sites, and it can be dangerous.   Should an exhaust leak develop or you just get the wrong breeze, you could be killed by carbon monoxide as you sleep.  Carbon monoxide is tasteless and odorless and is known as "the silent killer".

That brings up the subject of warning systems.   You must install smoke detectors in your RV to meet RV codes and for the safety of you and your traveling companions.  Carbon monoxide detectors are highly recommended.   LP Gas detectors are also required on commercially built units and you should plan on including one if you are building your own RV.  While RV propane systems are usually pretty robust and reliable, normal road vibration can cause connections to loosen and leak and you definitely want to know long before the concentration reaches a critical level, which is something around 22,000 parts per million.  Detectors are usually set to go off at about 1/10 that concentration, providing a good margin of safety.  Be sure to buy RV rated detectors.  Residential models won't stand up to the vibration and stress of travel.

Hybrid conversions.  I don't know what else to call them.  I use this term to describe travel trailers mounted on truck chassis.   The very first "motorhome" I ever encountered was built and owned by a neighbor back in Idaho.   He had removed the bed of an old pickup truck and mounted a small Shasta travel trailer.  This kind of work takes some heavy lifting and carefully engineered mounting but avoids all the tedious work of building cabinets, doing plumbing and wiring, and installing appliances and furniture.  You have ready-made living quarters.  For this kind of work you'll need some heavy duty hoists or cranes to lift the trailer and position it on the truck chassis.  You will have to design and build appropriate mounts and braces to attach the trailer to the truck frame. 

Building your own RV can be a very satisfying and rewarding, if time consuming, experience. Chances are, no matter how well you plan, you will encounter unexpected obstacles, costs, and delays or things that won't fit quite the way you thought they would.  Keep that in mind and be prepared for it.  I recommend setting aside at least an extra 20% (time and money) for surprises that come up along the way.

With all this in mind, creating a basic camping vehicle need not be an overwhelming job.  You may want to start small and get some practice before undertaking a major conversion.   It will also give you time to assess you needs and wants. My first "camper" was an old Chevy suburban that was a retired maintenance vehicle from a local school district. I didn't do any real "conversion" per se.   I just added curtains on the windows for privacy and stocked it with my tent camping equipment (stove, ice chest, sleeping bags).  A 3-gallon plastic water jug and and plastic dishpan provide for basic hygiene and washing dishes.  Essentially, it was my "tent on wheels".  It certainly wasn't fancy, but it sure was nice to roll into camp, roll out our sleeping bags in the back, and be ready for a good night's sleep while our fellow campers were out wrestling with their tents in the dark and the wind. And it was really pleasant to listen to the staccato sounds of the rain on the metal roof instead of worrying about our tent leaking in a downpour or listening to it flap in the wind.  Just imagine how much more secure (though a bit noisy) it is in hail!   Our trusty Coleman lantern was usually all the heat we needed in the limited space on cool evenings.  Technically, it couldn't be described as a motorhome, but it did provide a lot of camping convenience at very low cost.  An old van or StepVan would work well too, especially if they have stand-up head room, which my Suburban didn't.  It isn't much fun trying to get your pants on when you can't stand up.  That's where an SUV tent might have been a good addition but since that was before Suburban's were classified as SUVs, it wasn't an option at the time.   Of course you could always set up a cabin tent adjacent to your vehicle to serve as a dressing room and extended living area.  Today you can do wonders with an SUV and available accessories.

Do it yourself!