Home / Layout dimensions
Layout dimensions
Starting sizes for drawing small travel-trailer floor plans. Measure the exact part before cutting.
Mattresses
Sizes are width × length. An RV mattress maker lists these common sizes. Mattress labels vary, so buy the mattress before making a tight bed box.
| Mattress | Inches |
|---|---|
| Twin / twin XL | 38 × 75 / 38 × 80 |
| Full | 53 × 75 or 54 × 75 |
| Queen | 60 × 80 |
| RV short queen | 60 × 74 or 60 × 75 |
| RV bunk options | 28 × 75, 30 × 75, 30 × 80, 34 × 75 |
Source: RV Mattress size guide.
Bunks
Clearance is the open space above a mattress. There is no single RV bunk-spacing rule found; use the builder reference below as a planning target, then check the selected mattress thickness and the person who will sleep there.
| Item | Draw / safety number |
|---|---|
| Between lower and upper mattress | 30 in target used by a bunk builder |
| Above top mattress | 30 in target used by a bunk builder |
| Upper-bunk rail | At least 5 in above the top of the specified mattress |
| Upper rail count | Two rails, one on each side; wall-side rail continuous |
Builder clearance example · CPSC rail guidance. CPSC guidance is for manufactured bunk beds; treat it as a useful minimum safety check, not RV certification advice.
Dinette and seating
Use these as comfortable drawing targets, not a purchased-kit specification. A bench seat is the built-in seat; the table normally drops onto ledges to make the bed.
| Item | Size to draw |
|---|---|
| Bench depth / finished seat height | 20–22 in / 18 in |
| Table height / depth | 29–30 in / 24–26 in |
| Bench width per person | 20–24 in |
| Small two-person dinette bed | 38 × 72 in |
| Four-person dinette bed | 40 × 72 in |
A sold 38-in booth is 38 × 22 × 31½ in overall and converts to a bed; use its 22-in depth as a real RV example. Source: RecPro booth. The comfort targets have no single manufacturer standard found.
Galley
Keep a compact galley shallow so a person can still pass. A 12 V compressor refrigerator runs from the trailer battery; its amp draw changes as it cycles.
| Item | Size or draw |
|---|---|
| Counter height / depth | 34–36 in / 20–24 in planning target |
| Compact sink | 15 × 15 × 6 in; 11 × 9 in basin |
| Large RV sink example | 25 × 15 × 6 in |
| 3.3 ft³ 12 V fridge | 19 W × 18½ D × 32¾ H; cooling 2.5–3.3 A, 80 W test peak |
| 4.4 ft³ 12 V fridge | 19½ W × 23½ D × 43½ H |
| Two-burner cooktop | About 12–13 W × 18–20 D; confirm cutout from the chosen maker |
| Outdoor option | Slide-out or rear-hatch galley: draw a 24 D × 36–48 W work surface |
Sink source · 3.3 ft³ fridge source · 4.4 ft³ fridge source. Counter, cooktop and outdoor-work-surface numbers are planning targets; no single RV standard was found. Joe used a 12 V cooler cubby and left room for a future kitchen: his build note.
Aisle and standing room
| Item | Size to draw |
|---|---|
| Clear aisle beside galley or bed | 24 in minimum; 26–30 in preferred |
| Inside standing height | 76 in (6 ft 4 in), matching Joe's small trailer |
These are layout targets, not code minimums. The project brief describes Joe's interior height as 6 ft 4 in.
Entry door and windows
A rough opening is the framed hole before the door or window goes in. Lippert says its door “call size” is the rough opening, with ±⅛ in width tolerance.
| Opening or part | Size |
|---|---|
| RV entry-door rough openings | 24 × 68, 24 × 72, 26 × 72, 30 × 72 |
| Common RV window examples | 14 × 22, 18 × 18, 16 × 24, 24 × 36 |
| Roof vent fan opening | 14 × 14 in standard opening |
Lippert installation manual · RV window examples · Maxxair vent standard. Verify the actual maker's drawing before framing.
Wet bath and toilet
A wet bath is one waterproof room containing both shower and toilet. It saves space but requires sealed walls, floor, drain, ventilation and access to empty the toilet.
| Item | Size / weight |
|---|---|
| Small wet-bath drawing footprint | 24 × 36 in planning minimum; no universal sourced minimum found |
| Composting toilet, Nature's Head | 19 W × 19 D × 21 H in |
| Compact Weekender toilet | 18 W × 18 D × 16¾ H in |
| Fresh-water tank planning sizes | 10 / 15 / 20 gal = 83 / 125 / 167 lb of water |
Toilet dimensions · USGS: water weighs 8.34 lb per gallon. Add the tank and hardware weight separately.
Desk and computer station
Nathan's requirement (2026-10-11): a desk that holds two 27 in monitors and a computer. A 27 in monitor is measured across the diagonal. One current model is 24.07 in wide and 7.89 in deep on its stand, and up to 20.42 in tall. Dell S2725DS specifications
| Item | Size to draw |
|---|---|
| Two 27 in monitors side by side | About 48–50 in wide. Draw a 54–56 in desk so a lamp or a laptop fits beside them. |
| Desk depth | 28 in. The stand takes 8 in; OSHA says 20–40 in from the eye to the screen is the preferred viewing distance. OSHA computer workstation eTool |
| Desk height | 29–30 in, a standard writing-desk height. Planning target. |
| Clear floor behind the desk | 36 in so a chair can roll back and a person can stand up. Planning target; no single standard found. |
| Monitor weight | About 9.9 lb each with the stand (4.49 kg). displayspecifications.com |
Legal outside size
These are outside dimensions, not interior room. This short note is only a drawing guardrail; see legal-registration.html for the full Texas checklist.
| Rule | Limit or trigger | Source |
|---|---|---|
| Federal National Network width | 102 in maximum | 23 CFR 658.15 |
| Texas width | 8 ft 6 in (102 in) for vehicles other than passenger vehicles | TxDMV |
| Texas height | 14 ft from roadbed | TxDMV |
| Clearance lamps | At least 80 in wide: two front and two rear clearance lamps | Texas Transportation Code §547.322 |
Design numbers for my trailer
| Item | Size to draw | Source |
|---|---|---|
| Main bed, short queen option | 60 × 75 in | RV Mattress |
| Child bunk option | 30 × 75 in | RV Mattress |
| Bunk clearance / rail | 30 in clear; 5 in above mattress | builder / CPSC |
| Two-person dinette bed | 38 × 72 in | Planning target; 38-in booth |
| Dinette benches | 20–22 D × 18 H in | Planning target |
| Galley counter | 20–24 D × 34–36 H in | Planning target |
| Compact sink | 15 × 15 × 6 in | RecPro |
| 12 V fridge bay | 21 W × 19 D × 33¾ H in minimum | RecPro 3.3 ft³ |
| Clear aisle | 24 in minimum; 26–30 preferred | Planning target |
| Standing height | 76 in | Project brief (Joe's trailer) |
| Entry opening | 26 × 72 in | Lippert |
| Roof fan opening | 14 × 14 in | Maxxair |
| Desk for two 27 in monitors | 56 × 28 in, 29–30 in high; 36 in clear behind it | Dell / OSHA |
| Wet-bath option | 24 × 36 in | Planning target; no universal minimum found |
| Fresh water | 15 gal = 125 lb water | USGS |
| Outside body width | Keep below 80 in if avoiding clearance lamps; never exceed 102 in | Texas / TxDMV |
These are room-envelope numbers. Do not put them into trailer.js until Nathan chooses a layout and the actual door, windows, appliances, mattress and tank are selected.