Serg Supply  /  Van Builders  /  DIY Guide

Plan smart.
Build it right.

Everything you need to know before your first cut; realistic timelines, the correct build sequence, and the mistakes that cost builders weeks of rework.

Sprinter · Transit · ProMaster
All Skill Levels
Before You Start — Set Honest Expectations
Time Commitment
Plan Ahead
Van conversions take time — often significantly more than expected. The scope of your build, your experience level, and parts availability all affect the timeline. Don't start without a realistic schedule in place.
Budget Reality
Budget Up
Material costs vary widely depending on what you're building. Factor in tools, shipping, and unexpected needs. Most builders underestimate total cost — build in a buffer before you start ordering.
Skill & Support
Know Your Limits
Serg Supply kits are designed to be installer-friendly, but a van conversion involves multiple trades. Know where you're comfortable and where you should bring in a professional — especially for electrical and plumbing.
Build Phases — Do These in Order
Phase 01 Plan & Order Layout, budget, and order all materials before touching the van.
Phase 02 Rough-In Insulation, electrical wiring, plumbing lines — all before any panels go up.
Phase 03 Structure Ceiling, walls, flooring — the shell that everything attaches to.
Phase 04 Furnishing Cabinetry, bed system, kitchen — secured to floor and wall studs.
Phase 05 Test & Finish Electrical finish, trim, leak checks, full systems test before your first trip.
The 10-Step Build Sequence
01
Start Here
Planning & Layout Design
Measure every wall section individually — vans are not square. Build cardboard templates. Finalize your layout and order all materials before starting. Changing your layout mid-build costs weeks.
02
Critical
Insulation & Vapor Barrier
Havelock wool or Thinsulate for walls and ceiling. Install vapor barrier on any metal. This is your only chance — you cannot retrofit insulation without tearing down panels.
03
Electrical
Electrical Rough-In
Run all wire before panels go up. Use marine-grade tinned copper wire throughout. Label every run. Plan your fuse panel location early — changing wire routes after paneling is extremely difficult.
04
Plumbing
Plumbing Rough-In
Install water lines, tanks, and drain systems. Run a full leak test before covering with any panels. Far simpler to fix a leak now than after your walls are installed.
05
Exterior
Windows
Cut precisely, use butyl tape, seal every seam. Professional window installs include a lifetime warranty — if you're not confident, this is worth subcontracting.
06
Structure
Ceiling, then Walls
Ceiling first, always. Serg Supply ceiling kits are CNC-fit — use construction adhesive plus self-tapping screws. Panels must be level and plumb before walls go up.
07
Structure
Flooring
Subfloor first (minimum ¾″ thickness, load-bearing). Then finish floor — Loncoin vinyl is standard in Serg kits. Stow Step and Flooring Threshold Kit install at this stage.
08
Furnishing
Cabinetry & Furniture
Every cabinet must be secured into wall ribs or floor — never adhesive alone. Unsecured furniture becomes a projectile in an accident. Use appropriate fasteners for your van's specific rib pattern.
09
Electrical
Electrical Finish
Install outlets, switches, lights. Test every circuit — verify polarity, ground continuity, and voltage drop. All AC circuits require GFCI protection. Never skip bench testing before final panels close.
10
Final
Trim, Testing & First Trip
Add GoCode trim kit, caulk all gaps, install hardware. Run a full systems test — water, electrical, ventilation — before your first overnight. Take a short trip close to home first.
Non-Negotiable Safety Requirements
Safety Awareness
Van conversion involves power tools, vehicle modifications, and systems that carry real risk if installed incorrectly. This page is not a safety manual — it's a general overview. Always consult qualified professionals for electrical, plumbing, and structural work, and follow all applicable codes and manufacturer guidance.
  • Work with qualified professionals for electrical and plumbing systems
  • Follow all applicable local codes and vehicle manufacturer guidelines
  • Use appropriate personal protective equipment for every task
  • Understand the tools and materials you're working with before starting
  • Never assume — verify clearances, capacities, and compatibility
  • Test all systems thoroughly before occupying the vehicle

Serg Supply provides product kits and general build information. We are not liable for outcomes related to installation decisions. If you have questions about a specific installation scenario, contact us directly or consult a licensed professional.

Learned the Hard Way — By Builders Who've Done It
What Works
Order materials before starting
Serg kits have a lead time. Place your order, then prep the van while you wait. Doing it the other way adds weeks of idle time.
Cardboard template everything
Especially ceiling and wheel arch areas. A failed $20 cardboard test beats a failed $300 panel cut.
Oversize your electrical
Calculate your real load, then add 25%. Upgrading wire gauge after walls are up is a full teardown. Get it right the first time.
Start simple, add complexity later
Get power, lighting, and a bed working first. Live in it for a weekend. Then add a kitchen, shower, or solar expansion with real context for what you need.
Label every wire, every time
Future-you diagnosing a fault at a campsite will be grateful. Use heat-shrink labels or a label maker on every run.
Common Mistakes
Skipping insulation to save time
Condensation will find you. Mold in a sealed van is a health hazard and a full teardown. Insulation is not optional.
Assuming the van is square
It isn't. Measure every single section individually. A 2mm assumption error becomes a 12mm gap across a 6-foot panel run.
Running electrical after panels are up
Routing wire through a finished van is miserable and produces compromised work. All rough-in happens before any panel goes up — no exceptions.
Skipping roof fan / ventilation
A Maxx Air fan is not a luxury item. Condensation control, cooking ventilation, and summer heat management all depend on it.
Adhesive-only furniture attachment
Construction adhesive is a supplement, not a primary fastener. Every cabinet needs mechanical fasteners into ribs or floor — a hard brake stop will test everything.
Helpful Resources
Technical Reference Van Wiring Standards Approved wire specs, fuse sizing, ABYC voltage drop calculator reference, Blue Sea and Victron product guidance. Read Guide Professional Option Foundation Kit — We Install It Rather have Serg Supply handle the foundation? Our full installation package covers ceiling, walls, flooring, electrical, and more. Learn More Building Professionally? PRO Dealer Program Wholesale pricing, priority production, and dedicated account management for professional van builders and upfitters. Apply Now
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