Skoolie Repair in Rancho Santa Margarita for School Bus Builds
Written by Structural Repair Lead, Structural and Frame Lead, OCRV Center. Reviewed by RV Systems Lead
In shortA skoolie is ribbed steel skin riveted to hat channel ribs on a truck chassis. The roof raise splice band and the floor pan under the plywood are where almost every job starts.
What does skoolie repair involve?
Skoolie repair covers the school bus body itself: ribbed steel sides, hat channel ribs, roof raise splice bands, welded window delete plates and the original steel floor pan under the new plywood. Rancho Santa Margarita owners bring these builds to Yorba Linda for welding, sealing and structural work.
- The body is bolted to a truck frame, not welded as one shell
- A raised roof adds a horizontal splice all the way around
- Window deletes are welded plates that need proper edge treatment
- Floor rust hides under the plywood the builder laid
- Base vehicles
- Blue Bird, Thomas or IC bodiesOn International, Freightliner or Chevrolet chassis with DT466, ISB or 6.5L power
- Body construction
- Ribbed steel on hat channelRiveted skin panels over formed steel ribs, bolted to the chassis rails
- Roof raise
- Adds a continuous splice bandHorizontal joint around the entire body at the cut line
- Typical length
- 20 to 40 feetGVWR 14,500 to 33,000 lb depending on body and chassis
- Welding rate
- $210 per hourSame department as body and structural work, $5 body supplies per body hour
Last verified
A school bus body is one of the toughest passenger structures built in North America, because it was engineered to protect children in a rollover. Ribbed steel sides riveted to formed hat channel ribs, a heavy steel floor pan, and the whole body bolted to a medium duty truck chassis. Owners convert them because that structure is genuinely good and because the vehicles are cheap.
Then they cut it. Almost every skoolie has had windows deleted and plated, a roof raised, or both, and the quality of that cutting and welding is what determines whether the vehicle is sound. That is where our work on these usually begins.
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Note
A skoolie is a converted yellow school bus: a body on frame vehicle with ribbed steel sides riveted to hat channel ribs, sitting on a Blue Bird, Thomas or IC truck chassis. A Prevost or MCI intercity shell converted by a coachworks is a bus conversion, a monocoque structure with a different budget entirely, and it has its own page.
Ribs, skin and a chassis underneath
A school bus body is ribbed steel skin riveted to formed hat channel ribs at roughly twenty eight inch spacing, with a heavy steel floor pan tying it together and the whole body bolted to a medium duty truck frame through body mounts. It is a genuinely strong structure and it was validated for rollover with children inside it.
The important consequence for a builder or a repairer is that the ribs are the only real structure in the wall. Everything else is skin. A cabinet, a bed platform, a wood stove or a roof rack has to reach a rib to be properly attached, and the timber framing most builders add between the ribs is not a substitute for that.
- Hat channel ribs are the load path, roughly every twenty eight inches
- Skin panels are riveted and carry very little vertical load
- The steel floor pan is structural and it is under the new plywood
- Body mounts were sized for seats and passengers, not a build
The roof raise is the highest risk joint on the vehicle
Raising a roof means cutting every rib and every skin panel horizontally all the way around the body, adding an extension piece to each rib, and closing the outside with a splice band. Done well it is strong and dry. Done in a driveway with self tapping screws and a tube of sealant, it is a continuous leak path at eye level with dozens of interruptions.
We inspect these from inside wherever we can, because the outside tells you very little. The perimeter interior sheathing comes off, we look at how each rib extension was joined and whether the band is fastened into the rib or only into the skin, and we probe the framing behind it for water that has been running down inside the wall.
Before you proceed
If a roof raise splice band is fastened only into the skin and not into the rib extensions, the joint is carrying load it cannot carry. Sealing it does not address that.
What is under the plywood
Every school bus has a steel floor pan with drainage holes, hundreds of seat bolt holes, and years of being mopped out. Converters generally lay foam board and plywood straight on top of it and never see it again. The rust that was starting underneath continues in a sealed cavity with no airflow, and it accelerates rather than stopping.
It surfaces as a soft spot at the stepwell or over a rear wheel arch, which are the two places water pooled when the bus was in service. By then the plywood has to come up. We tell buyers to establish this before purchase, because a floor pan repair on a finished build means dismantling the interior above it.
Welding plates into ribbed steel
Deleting a window sounds simple and is not, because school bus side panels are ribbed with a formed profile. Welding a flat plate into a ribbed opening leaves gaps that get filled with sealant, and the weld heat destroys the coating on both sides of the joint in a panel that will never be seen from inside again.
The right approach is a plate formed to match the rib profile, welded with the heat affected zone treated on both faces, and an exterior finish that does not rely on sealant to close a geometric gap. When we rework somebody else's delete, most of the hours go into removing filler and sealant to see what is actually under it.
Rates and where skoolie budgets go wrong
Welding, fabrication, structural and body work all bill at $210 per hour with body supplies at $5 per body hour and paint supplies at $55 per paint hour. Electrical and systems work is $260 per hour. A written estimate is $150, credited in full against an authorized repair, and deposits are fifty percent over $2,000.
The recurring budget mistake on these builds is treating steel work as the cheap part. It is not, because access dominates. Reaching a splice band or a floor pan on a finished interior means removing finished work, and that removal and reinstatement is frequently larger than the weld itself.
Who brings skoolies in
Mostly builders partway through, who have reached the point where the remaining work needs welding, a lift, extraction or a measured assessment. That is a good stage to arrive at, because the interior is not finished yet and access is still cheap. We are happy to do the steel and hand the interior back to the owner.
The other group is second owners of finished builds who have discovered a leak or a soft floor. Those are harder conversations because the finished interior is in the way. Either way, all of this happens in shop at Yorba Linda: there is no mobile service and no roadside option, and a skoolie needs a welding bay rather than a driveway.
How a skoolie is built
| System | What it is |
|---|---|
| Wall system | Ribbed steel skin panels riveted to formed steel hat channel ribs on roughly twenty eight inch centers, with the body bolted to the chassis rails through body mounts, minimal factory insulation and a builder installed interior of framing and sheathing inside the ribs |
| Roof system | Ribbed steel roof panels riveted to the same ribs, very commonly cut and raised by the converter with a fabricated vertical extension in each rib and a horizontal splice band running the full perimeter of the body |
| Chassis | International, Freightliner or Chevrolet medium duty conventional or flat nose chassis, DT466, Cummins ISB or gasoline power, leaf spring suspension, hydraulic or air brakes depending on GVWR |
| Typical length | 20 to 40 feet |
| Typical GVWR | 14,500 to 33,000 lb |
What typically goes wrong on this vehicle
Water entering along the roof raise splice band
Raising a roof means cutting every rib and every skin panel horizontally around the entire body, then adding an extension and closing the joint with a band. That creates a continuous seam at roughly eye level with dozens of fastener or weld interruptions, and unlike a factory seam it was closed once by hand with no validation. It leaks at the corners and above the windows first.
How we repair itRust in the steel floor pan hidden under new plywood
Every school bus floor has a steel pan under the original rubber matting, and that pan has drainage holes, seat bolt holes and years of mopping behind it. Converters lay insulation and plywood on top without addressing what is underneath, so rust continues in a sealed cavity. It usually surfaces first as a soft spot at the stepwell or over the rear wheel arch.
How we repair itWindow delete plates weeping or corroding at the weld line
Deleting a window means cutting the opening out and welding a plate into ribbed steel that has a formed profile, not a flat one. Fitting a flat plate to a ribbed panel leaves gaps, and the heat affected zone loses its coating. Sealed and painted over, it looks fine and corrodes from the inside of the weld outward.
How we repair itBody mount bolts loose or elongated at the frame rails
The body is bolted to the chassis through a set of mounts sized for a bus carrying seats and children. A conversion adds several thousand pounds of framing, tanks, batteries and appliances, much of it high or at the ends. Those mounts see loads they were not sized for, and elongated holes are common on builds with a few thousand miles on them.
How we repair itCabinetry and appliances fastened between ribs rather than to them
The only real structure in a bus wall is the hat channel rib every twenty eight inches or so. Builders frame between them with timber and then hang a galley or a wood stove off that framing. Over a few thousand road miles the fasteners work, and because the framing is not tied back to the ribs the whole assembly moves as one.
How we repair itWhat common jobs run on this vehicle
Roof raise splice band rework and sealing
$3,500 to $18,000+
20 to 80 labor hours at $210 per hour, body and paint.
- Body supplies at $5 per body hour.
- Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
- Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
- A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.
- Interior sheathing has to come off the perimeter to reach the joint properly. Sealing from outside alone does not survive a season.
Floor pan rust repair under builder plywood
$750 to $9,500+
6 to 40 labor hours at $210 per hour, body and paint.
- Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
- Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
- A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.
Window delete plate rework and refinish
$750 to $20,000+
5 to 80 labor hours at $210 per hour, body and paint.
- Paint supplies at $55 per paint hour.
- Body supplies at $5 per body hour.
- Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
- Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
- A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.
Body mount inspection and replacement
$2,000 to $12,000+
10 to 55 labor hours at $210 per hour, body and paint.
- Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
- Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
- A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.
Interior re-anchoring to the rib structure
$500 to $7,500
4 to 35 labor hours at $210 per hour, body and paint.
- Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
- Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
- A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.
Will it fit in the shop?
A raised roof skoolie is one of the taller things we take in, frequently twelve feet six to thirteen feet six after a raise plus roof deck and solar, and it clears our sixteen foot doors with margin. Length up to forty feet is not an issue for bays or booth. What these builds need is welding bay time with proper extraction and fire watch, because we are cutting and welding steel inside a vehicle that contains timber framing, insulation and often a wood stove, and that work does not share a bay with refinish.
Insurance considerations for this vehicle
- Registration and classification vary by state and they matter here. A bus still titled as a bus, insured as a bus, is a different claim from a vehicle retitled as a motorhome, and the difference decides whether the interior build is covered at all.
- Work done by a previous builder is excluded as faulty workmanship almost universally. A leaking roof raise splice performed by someone else is an owner expense, and it is better to hear that before a claim is filed than after it is denied.
- Photograph and inventory the build with receipts. On a skoolie there is no MSRP, no build sheet and no comparable, so the owner's documentation is the only thing establishing what was in the vehicle.
Appendix: questions and answers
- My raised roof leaks above the windows. What is failing?
- The splice band. Raising a roof cuts every rib and skin panel horizontally around the body, and the band closing that joint is a hand made seam with dozens of interruptions. Corners and the run above the windows go first. We take the perimeter interior sheathing off to see whether the band reaches the rib extensions.
- Is there rust under the plywood floor in my converted bus?
- Very likely. Every school bus has a steel pan with drainage holes and hundreds of seat bolt holes, and builders lay foam and plywood straight over it. The rust that was starting continues in a sealed cavity with no airflow. It shows up first at the stepwell or over a rear wheel arch.
- What do I actually screw a galley into in a bus wall?
- A hat channel rib, which sits roughly every twenty eight inches. The skin between ribs carries almost no load, and the timber framing most builders add between them is not a substitute. Anything heavy, including a bed platform or a wood stove, needs a fastener path that reaches a rib.
- Why is my welded window plate rusting through the paint?
- Because a flat plate was welded into a ribbed panel and the gaps were filled with sealant, and because the weld destroyed the coating on both faces. It corrodes from inside the joint outward. A correct delete uses a plate formed to the rib profile with the heat affected zone treated on both sides.
- Do the body mounts need attention after a conversion?
- They should be checked. Those mounts were sized for a bus carrying seats and children, and a build adds several thousand pounds of framing, tanks, batteries and appliances, often high or at the ends. Elongated mount holes are common on builds with a few thousand miles on them.
- Should I bring my bus in before I finish the interior?
- Yes, if any steel work is needed. Access is the expensive part of every skoolie job, and once the interior is finished, reaching a splice band or a floor pan means dismantling completed work. We are glad to do the welding and structural repairs and hand the interior back to you.
Open a file on this repair
Tell us the vehicle, what happened and whether a claim is open. We will tell you what the scope looks like and what it takes to get you back on the road.
Or call (949) 799-3387