Bunkhouse Fifth Wheel Repair, Second Door and Bunk Room Work
Written by Structural Repair Lead, Structural and Frame Lead, OCRV Center. Reviewed by RV Systems Lead
In shortA bunkhouse layout cuts a second entry door into the rear sidewall and puts a sleeping room over the rear overhang. That extra opening plus overhang loading is the whole difference.
What is specific to bunkhouse fifth wheel repair?
Bunkhouse fifth wheel repair deals with the second entry door cutout weakening the rear sidewall, bunk room floors over the rear overhang, and a half bath crammed into a rear corner. Rancho Santa Margarita families bring these to our Yorba Linda shop for that work.
- Two entry doors mean two large cutouts in one sidewall
- The bunk room usually sits over the rear overhang
- A half bath in a rear corner concentrates plumbing there
- Rear ladders and bike racks load the bunk room wall
- Layout
- Rear bunk room, second entry doorQuad or double bunks with an independent door, frequently plus a rear half bath
- Sidewall
- Two door cutoutsBoth openings in the same wall, one of them behind the axle group
- Overhang
- Bunk room behind the axlesSleeping load applied to the cantilevered rear section of the frame
- Typical length
- 33 to 42 feetGVWR 13,000 to 17,000 lb with two or three slide rooms
- Body rate
- $210 per hourPlumbing and systems work at $260 per hour
Last verified
A bunkhouse fifth wheel is a family layout, and families need a second door. So the builder cuts another entry opening into the rear third of the same sidewall that already has the main door, adds a sleeping room over the rear overhang, and very often squeezes a half bath into a rear corner so children are not walking through the master.
Each of those decisions is sensible for living and awkward for structure. Two large cutouts in one wall, sleeping load on a cantilever, and plumbing in the corner of the trailer furthest from everything else. That is what we end up repairing on these.
Two doors in one wall is the design compromise
A single entry door in a laminated sidewall is a well understood opening with a header, posts and enough continuous material around it. Add a second door in the rear third of the same wall and the runs of continuous laminate between openings get short, and the header over the rear door has less material either side to carry into.
On a bunkhouse that rear door is also frequently behind the axle group, in the part of the sidewall that flexes with the overhang. So the opening with the least structural margin is in the location with the most movement, which is why cracks on these trailers start at the upper corners of the rear door rather than anywhere else.
- Short continuous laminate runs between the two openings
- Rear door header has less material to carry load into
- The rear opening sits in the flexing overhang section
- A bunk room slide removes still more continuous wall
Sleeping weight on a cantilever
The bunk room is behind the axles, so everything in it is applied to a cantilevered floor. The engineering allowed for children in bunks, and the engineering was correct. What it did not allow for is a decade of children climbing into a top bunk by standing on the bottom one and jumping down again, which applies impact rather than static load.
The result is a floor that flexes noticeably at the rear of the bunk room. We probe it from below through the rear storage area, because from inside the carpet and the bunk structure hide everything. Reinforcement over the overhang is straightforward once the trailer is supported at ride height and the floor edge is accessible.
Note
Flex at the rear of a bunk room floor is normal to a small degree and worth measuring rather than guessing. We compare deflection loaded and unloaded before recommending reinforcement.
A half bath in the worst corner of the trailer
Families want a second bathroom and the only place left is a rear corner, so a toilet flange, a shower pan, a sink drain and a vent stack all end up within a few square feet at the point furthest from every other plumbing run. Supply lines reach it along the outer wall, which is the coldest part of the trailer and the part that flexes most.
That combination produces the leaks we find: a flange seal working loose on a flexing floor, a pan joint opening at a corner, a supply fitting that split during a cold night on a long run against an outer wall. Tracing them means opening the corner rather than resealing what is visible.
Ladders and bike racks on the least supported wall
The rear ladder anchors to the bunk room rear wall and a bike rack hangs off the rear bumper. Both apply load to the least supported part of the trailer, at the same time as the room inside carries sleeping weight on a cantilever. The ladder top bracket goes first, because it takes a live load every time anybody climbs it.
Rear bumpers on towables are not rated as load carriers, and a loaded bike rack on a bumper cantilevered off an overhang is one of the most reliable ways to damage a rear wall. When we re-anchor these we spread load into the frame rather than the bumper tube, and we say plainly when a rack should not be there at all.
The slide that only binds when you are packed
This is one of the most common calls we get on a bunkhouse. The bunk room slide works perfectly in the driveway and binds at the campsite. Owners reasonably conclude the mechanism is intermittent, and it is not: the trailer is loaded at the campsite and empty at home.
Loaded, the overhang deflects slightly and the slide opening in an already weakened sidewall racks. We test these loaded, or we load the trailer here, because a slide diagnosed empty on a bunkhouse tells you very little. Measuring opening diagonals in both states is what identifies the real problem.
Rates and who owns bunkhouses
Body, laminate, structural and interior work bills at $210 per hour with body supplies at $5 per body hour and paint supplies at $55 per paint hour. Plumbing, slides and appliances are $260 per hour. A written estimate is $150, credited in full against an authorized repair.
These are family trailers and they get used hard for six or eight years and then sold. Second owners inherit a bunk room that has taken a decade of impact load and a rear door opening that has been flexing since new, which is why a measured inspection before purchase is worth far more on a bunkhouse than on most towables.
How a bunkhouse is built
| System | What it is |
|---|---|
| Wall system | Laminated sidewalls over aluminum tube framing with two entry door cutouts in the same wall, additional header and post framing around each opening, and frequently a slide room opening in the bunk room as well, leaving limited continuous wall between them |
| Roof system | One piece TPO or EPDM over composite decking, with a second roof vent and often a second air conditioner over the bunk room, plus a rear ladder anchored to the bunk room rear wall |
| Chassis | Lippert steel frame with a raised upper deck at the pin, tandem 5,200 to 7,000 lb axles, and a rear overhang behind the axle group carrying the bunk room floor and the rear bumper accessories |
| Typical length | 33 to 42 feet |
| Typical GVWR | 13,000 to 17,000 lb |
What typically goes wrong on this vehicle
Cracking at the corner of the second entry door cutout
Two door openings in one sidewall leave short runs of continuous laminate between and beside them, and on a bunkhouse the rear door is frequently behind the axle group where the wall is also being flexed by the overhang. Cracks start at the upper corners of that rear opening because the header there has the least material to carry it.
How we repair itBunk room floor flexing over the rear overhang
The bunk room sits behind the axle group, so the weight of two to four sleeping children plus a bunk structure is applied to a cantilevered floor section. That floor was designed for the load, but it was not designed for children using the top bunk as a diving platform, which is what actually happens.
How we repair itLeaks and staining in the rear corner half bath
Putting a second bathroom in a rear corner means a toilet flange, a shower pan, a sink drain and a vent stack all inside a few square feet at the furthest point from the main plumbing runs. Long runs to a rear corner freeze the fittings against the outer wall and every joint is in the coldest, most flexed part of the trailer.
How we repair itRear ladder and bumper rack pulling on the bunk room wall
The rear ladder anchors to the bunk room rear wall, and owners hang a bike rack off the rear bumper on the same overhang. Both apply load to the least supported part of the structure while the room inside is carrying sleeping weight. Ladder top brackets pull first because they take a live load every time somebody climbs.
How we repair itBunk room slide binding when the trailer is loaded
A slide opening in the bunk room removes still more continuous wall from a sidewall that already has two doors in it. When the trailer is loaded and the overhang deflects slightly, that opening racks, and the slide binds only when the trailer is packed for a trip. Unloaded in the driveway it works perfectly, which makes owners think it is intermittent.
How we repair itWhat common jobs run on this vehicle
Rear door cutout corner repair and header reinforcement
$1,500 to $20,000+
10 to 100 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.
- The interior panel comes off to reach the header. Repairing the laminate outside without reinforcing the opening returns the crack.
Bunk room floor reinforcement over the overhang
$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.
Rear half bath leak trace and fixture repair
$200 to $5,500
1 to 25 labor hours at $260 per hour, mechanical and electrical.
- 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.
Rear ladder and bumper rack re-anchoring
$1,500 to $10,000+
8 to 45 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.
Bunk room slide opening re-square
$1,500 to $7,500
10 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 42 foot bunkhouse fits our bay doors and the sixty foot booth without stripping the roof. What these jobs need is interior access from two directions at once: the rear door opening work is done from inside with the panel off while the exterior laminate is worked from a platform outside, so we allocate a bay with clear space on the door side rather than parking it against a wall. Overhang and floor work is done with the trailer supported at ride height on the frame.
Insurance considerations for this vehicle
- Door cutout cracking is structural fatigue and reads as wear. If a crack coincides with a collision or a jackknife, the file has to show the impact path reaching that opening, which means photographs of both door gaps before disassembly.
- Water damage traced to a rear half bath fitting is usually treated as a plumbing failure rather than a covered peril, and any resulting floor damage as a consequence of it. Sudden supply line ruptures are sometimes payable and slow drain leaks essentially never are.
- Rear bumper mounted bike racks are a documented exclusion on several carriers, because the rear bumper on a towable is not rated as a load carrier. Damage that starts at a bumper rack often takes the whole rear wall claim with it.
Appendix: questions and answers
- Why do cracks start at the corner of my rear entry door?
- Because that opening has the least structural margin in the most active part of the wall. Two doors in one sidewall leave short runs of continuous laminate, the rear header has less material either side to carry into, and on a bunkhouse that opening usually sits in the flexing overhang section behind the axles.
- How much flex is acceptable in a bunk room floor?
- A small amount is normal, because the room is cantilevered behind the axles. What matters is the change. We measure deflection loaded and unloaded and compare, because a decade of children climbing into a top bunk applies impact rather than static load, and that is what eventually softens the floor.
- Why is my rear half bath the part that always leaks?
- It is in the worst corner of the trailer. A toilet flange, shower pan, sink drain and vent stack sit in a few square feet at the point furthest from every other run, and the supply lines reach it along the coldest, most flexed outer wall. Every one of those joints is in a bad location.
- My bunk room slide only binds when the trailer is packed. Intermittent fault?
- No, it is loading. Packed, the rear overhang deflects slightly and the slide opening in an already weakened sidewall racks. Empty in the driveway it works perfectly. We test loaded, or load the trailer here, and measure the opening diagonals in both states to identify what is actually moving.
- Can I mount a bike rack on the rear bumper of a bunkhouse?
- We advise against it and several carriers exclude the resulting damage. A towable rear bumper is not rated as a load carrier, and hanging bikes off a bumper that is itself cantilevered behind the axles is a reliable way to damage a rear wall. A frame mounted carrier is the alternative worth doing.
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