I have converted many over-the-road coaches over the years and a couple of school buses, as you can read about in the numerous articles I have published in BCM over the years.  Many were very high-end conversions.  In this article, I will point out some differences in bus conversions, including the advantages and disadvantages of school bus conversions compared to an over-the-road coach.  

School buses are less expensive to acquire and if they were recently in service, they should be roadworthy. In contrast, if you buy a used coach, even if it has been in service, they may not have changed the oil or properly maintained it recently, as they probably knew it would be sold soon.  School buses are less expensive to purchase than over-the-road coaches; generally. However, the cost to convert a school bus is the same, or even more, and more time-consuming than an over-the-road coach.  One thing I can tell you is that converting any bus will cost you about twice what you estimate it will after you add in all of the screws, nuts, bolts, nails, etc., required to finish the bus.

Once you decide what length bus you are interested in based on your needs, your next step is finding the right bus to convert and what to look for. Every basic bus conversion costs about $75,000, and it can go up from there. That is just for the interior buildout and does not include any work to the shell. If the bus has body damage or rust, it can easily double the basic conversion cost. I did so for me on the RTS and Spaceliner I converted. Both were cheap buses to start with and the Spaceliner was free. Rust is usually not as much of a problem with school buses. All the ones I went through were rust-free. 

Tires are costly if needed, but they are easy to inspect. Look for tread wear and check the dates on the tires.  Generally, any tire over seven years old should be replaced. Also, make sure the tires come with the bus. Some tires, like those on transit buses, are leased and are removed when the bus is sold. 

Next are the brakes. Most brakes have open spiders, and you can visually inspect the brake shoes by looking in from the back of the wheels. If the bus has disc brakes, you may have to pull a wheel to do the inspection.  

The next significant expense will be the engine. If it is a diesel engine, look for cold engine smoking. If the bus is running and warmed up when you get there, it may no longer smoke. Be aware of this deceptive sales practice. Always ask the seller to not start it the day you plan to arrive.  The same goes for gas engines, but high mileage is more of a problem with gas engines because their service life is much shorter than a diesel engine. 

You have to decide if you want an automatic or a standard transmission.  Most buses now come with automatic transmissions; however, some people prefer a manual transmission where they can have full control of the shift points.  Just be cognizant that as much as you like shifting on the hills, only one in ten buyers now will buy a bus with a standard transmission, limiting its resale value.  The automatic or manual transmission can only be evaluated in a road test. At that time, check the top speed of the bus. You will not have to go 80 MPH to check that. You can estimate it by the RPM at lower speed or in lower gears. 

If the bus has airbags, check for leaks and how long they stay inflated. There are specifications for that. Look it up. Good airbags should remain fully inflated for several days. If you shut the engine off and you hear air leaking, it may require you to replace an airbag. Usually, if one bag is leaking, you may as well replace all of them simultaneously, as the rest are ready to fail. 

However, it may be a line or a valve leaking. The only way to know is to crawl under a bus, so wear your old clothes when looking at buses. However, if the bus has airbags, never crawl under a bus without first blocking up the body or have someone experienced in mechanics check this out for you. If an airbag or airline fails when you are under the bus, it can drop and kill you.

If the bus has regular springs, check for broken or cracked springs or leaves. How much have they worn? Are they overloaded or deformed by age? Also, check all lights: headlights, stoplights, flashers, and turn signals.  Also, check the windshield wipers and windshield washers. 

On the inside, check how much work it will take to change the entrance door, or can you live with the bifold door that came with the bus? Most people enjoy driving down the road with the door open for fresh air, which you can do with a bifold door. 

How easy will it be to remove all of the seats if they are still in the bus? Removing seats can be a real pain if it is an older bus due to rusted bolts. The bolts may have to be but off using a grinder.  If you can have the seller remove the seats, it will save you the hassle of doing it yourself, and you won’t have to dispose of a pile of seats. Seats are hard to sell, and many end up in the landfill which can be expensive to dispose of, unless you repurpose them as Mary did in this article. Besides, they may be able to use them in another bus if they are in decent shape.

Is the floor soft and spongy?  If it is, it is probably water-damaged and either rotted or rusty. Can you see any signs of water leaks from the roof and windows? Does it have a flat floor, and if not, how far do the fender wells protrude to the inside?  The more they protrude, the harder it is to build cabinets and furniture around, which is not an issue with an over-the-road bus which have flat floors.  Are the walls straight, and is the roof flat and square to the walls? Curved walls and roofs caused by leaks and rust will add to the work required before you even start your conversion, delaying the date you may plan to take your first trip. 

I once got a bus free, and I converted it into a mobile office for job sites when I worked at a specific location for several weeks at a time. It worked well for that, and the higher ground clearance than a coach-type bus made it easier to move around the construction site.  When that job was finished, I sold the bus for $18,000, so it cost me nothing for my mobile office as all I had into the bus was a paint job to paint it white as privately owning a school bus yellow bus is not allowed in most states.

I obtained several gas-powered school buses for free back then, as there was no market for them. I could fix them up a little bit and sell them a small profit for construction buses and a few to converters, even though converting school buses was not very popular in the 1970s. Most of these were Bluebird buses, which were the most popular back then. 

The main problem with converting a school bus over a coach-type bus is where to put the tanks. Most school buses do not have luggage bays underneath where liquids nicely drains into.  If you sling them underneath a bus without protection, rocks, sticks, and other road debris can bounce up and puncture them.  If you frame them in for protection, you cannot easily access the tanks for service, but it will protect them better from freezing, which can be an issue depending on where you travel.  Whereas with a coach bus, all tanks can go in bays, protected from the elements, easily accessible, and can be heated.

Fresh water tanks are not as problematic as they can be located under the bed or sofa. You can easily fit a 110-gallon tank under a double bed between the wheel wells. They can be drained with a ½” diameter hose, unlike a gray or black tank that requires much larger plumbing. Of course, if you have a rear-engine bus, you may have to remove not only your bed but also your fresh water tank to access the top of the engine, making engine access more challenging and time-consuming.  However, if the tank or plumbing starts leaking above the floor, it can create a lot of water damage. Whereas tanks in a bay in an over-the-road bus will not damage as much if they start leaking.

Gray and black water tanks can be more problematic.  The black water tank must be positioned more or less under the toilet.  A straight drop is recommended, but you can add an elbow and a short pipe under the toilet if the tank has to be shifted off to one side a little bit. But anything that impedes the flow of “solids” will require more water to flush them into the tank.  When boondocking, this can be a concern. This being said, the toilet is one of the first things you position in a bus conversion. 

The gray water tank can go almost anywhere, but the preference is to locate it as close to the shower and sink drains as possible.  If the drain lines get plugged up as they sometimes do, the less piping you have to deal with, the better.  However, the bottom line is that water only flows downhill, so both the black and grey water tanks need to be placed below the floor unless you want to deal with a pumping system to pump the liquids and solids to a tank above the floor.  Which, if they are above the floor, they also take up floor space.

The other concern with placing any tanks below floor level in a Skoolie exposed to the elements is that, as noted before, rocks, sticks, and other debris can bounce up from the road and break or crack the tank or a pipe. Then, you have a mess on your hands, and damages like this need to be fixed ASAP. No RV Park will allow you to stay in their park, on BLM land, or in a parking lot, as that creates a biohazard with leaking black or grey water pipes or tanks. This is not a problem in a coach build as everything is protected inside a luggage compartment, including all plumbing.  

Some people will frame out an area under the toilet to position the tank above the floor. Some toilets even come with a built-in tank holding tank.  This is fine, but it becomes awkward for some people to use the toilet due to its height. This can also be done with a shower, but only if you do a roof raise, which costs more money and reduces the likelihood you will be able to insure your bus.  Insurance companies frown on body modifications to your factory-built bus, as several people have found out the hard way.

However, with shower water, you can use a pump to pump the wastewater back up above the floor into a tank above the floor. It works in theory; however, very few pumps will not clog up when you pass shower water, soap, hair, and other stuff through them. Filters help, but you may be changing filters way too frequently. You can do the same with black water; however, that requires a macerator pump. You can also buy a macerator toilet, which pumps everything into a tank above or not directly below the toilet. With these, you can drain your tank through a 5/8” diameter garden hose.

The other problem with putting tanks above the floor is that many people use simple rectangular tanks that do not drain very well.  When converting a coach, there is more room to work with, and sloped tanks can be built in, which naturally drain much more completely so solids do not build up inside as easily.  Also, tanks located inside the bus tend to be relatively shallow, and for black tanks, it is better to use taller tanks that can build up more “head pressure” to help them drain more thoroughly. 

One advantage of having tanks inside a bus is to prevent them from freezing.  Tanks seldom freeze because of their volume, and by pouring salt down the drain, it will only be like a sludge but will still drain.  However, you cannot do that with the freshwater tank. The problem lies in the smaller surface areas, such as the piping in and out of the tank. The smaller lines tend to freeze first, and having a frozen line in your bus is not only a hassle, but when it thaws, it can split the pipes and fittings, creating a flooding hazard as they thaw out and causing a lot of damage to your bus and your appliances.  That is another advantage of a coach: all tanks are located in the bays below, and if they leak, you only damage what is in each bay, and you can efficiently heat a bay to prevent pipes from freezing.

The other drawback with converting a school bus, as noted before, is the wheel wells.  Almost all school buses have wheel wells, whereas coaches are built with the floor higher off the ground, so there are no wheel wells to build around.  Wheel wells are also often an area you need to check for rust as they tend to rust out before anything else on the bus because of the tires slinging dirt, salt, rocks, and other debris against them when traveling.  Many Skoolie people have to rebuild their wheel wells before they can start their conversion.

When building cabinets etc., round wheel wells have to be built around. Storage space that would be available under a sofa is not available if you have a wheel well in the way. Also, if you buy furniture, you are limited in where it can go in your bus.  Anything fitting around the wheel wells must be custom-made.  Building around it is not a problem, but it is one more obstacle to deal with, and you have to be concerned about leaks that may occur while driving on rainy days.  

You also need to ensure that the wheel wells are completely sealed before you cover them; otherwise, you may see little puddles around the cabinets or whatever you built around your wheel wells. Again, this is another issue you do not encounter when converting a coach-type bus.

There are some advantages to converting a school bus. They have a higher ground clearance, so you can go more places in them. One disadvantage is that they are very rough riding. Most have the same suspension as a heavy-duty truck. They are designed to travel short distances twice a day but are not designed to travel cross-country for several hours per day as RVers frequently tend to do.

Some people keep their school bus conversions very simple. Some shorter Skoolies do not have a shower, which takes up a lot of space and requires more storage for fresh water and a larger grey water tank. If you buy your fuel at truck stops, you can use nice, large showers for free in many places.  

There are also Planet Fitness centers all over the U.S., and many people go there to shower. The only disadvantage is that you may have to drive way off the main road to find them, which can be inconvenient if traveling cross-country on a tight schedule. That is when it is nice to have your own shower onboard, so you can jump in and out in a hurry and hit the road again, and you can leave all of your supplies in your shower when traveling.

Most school buses do not have a washer/dryer onboard.  They are a luxury, especially for full-timers, and especially if you have a dirty job where you must change your clothes frequently.  However, there are laundromats in almost all truck stops. Again, it takes time to find them, and then you have to wait around until all of your clothes are dry, but the good thing is, you can do all of your clothes at the same time, and you don’t need to carry extra water and don’t require a larger grey water tank just for the washing machine. If you have a large bus and no toad, parking near a laundromat other than in a truck stop can be tricky.

I prefer having my own laundry machine for several reasons as you can read HERE.

Most school buses do not have large, high-quality RV-type generators built into their luggage bays. They use portable generators instead. Some entertainer coaches have five roof air conditioners to keep the interior cool in the hot summer months.  People who convert school buses usually install one mini-split air conditioning unit that is sufficient for their needs, as they tend to follow moderate climates more.  Staying in southern Arizona in the summer with one mini-split just doesn’t cut it.

They will venture north in the summer and south in the winter, where the temperature is more conducive to camping. Generators can be built into the side of the bus by cutting a hole and framing it in, but most carry them inside or on their rear bumper.  A large generator is generally unnecessary unless you run two or more roof air conditioners.  Of course, the amount of insulation and number of windows you have in your bus makes a significant difference in how comfortable you will be, as you can read in this article.

The standard inside height of a bus is 75”. If you use strapping and plywood to add insulation, it lowers the ceiling to even less than that.  If you use roof air conditioners, you lose 2”, usually in the center aisle of your bus.  You can use a bus with the standard height if you are not too tall. The problem is usually in the shower because it is always on the side of the bus, where there is a curved ceiling lowering the height.  Some people add a sunken floor in their shower or a roof window to gain more headroom. But those tend to be too hot in the summer and too cold in the winter. Short of raising the roof, there are limitations.

Shuttle buses are also an option for some people. They are generally smaller and lower to the ground, which is helpful if you have mobility issues. They also have large windows and excellent heat and air conditioning, designed for people to go in and out of them all day with luggage. The main drawback of a shuttle bus is that they are built low to the ground so people can get in and out of them quickly at airports, so there is minimal room for storage tanks underneath, and ground clearance can be an issue for boondocking. Click HERE for an article on converting a shuttle bus.

I have converted many buses, both over-the-road buses and school buses, and I have experienced the advantages and disadvantages of traveling and living in both. Over-the-road buses are easier to convert and, when finished, ride much better. School buses have the advantage of lower cost to buy and operate and are also more suitable for boondocking due to their higher ground clearance. Bottom line: It depends on how many miles you plan to travel each day and how comfortable you want to be, or if you are into frequently boondocking way off the beaten path. In the end, both bus types cost about the same to convert.