Building Types
20x40 RV Carport
- Width
- 20 ft
- Length
- 40 ft
- Floor area
- 800 sq ft
- Perimeter
- 120 ft
Configuration
How This Building Is Configured
Configuration summary
| Building type | RV Carport |
|---|---|
| Footprint | 20 ft × 40 ft |
| Floor area | 800 sq ft |
| Eave height | 10 ft |
Example
Example Configuration
Quick dimensions
At a Glance
Width
20 ft across the gable end.
Length
40 ft along the sidewall.
Floor area
800 sq ft of clear floor.
Eave height
10 ft at the sidewall on the stored profile.
Access
Doors & Access Considerations
Opening width
Across a 20 ft gable end, the practical opening width is limited by the frame and confirmed with the supplier.
Opening height
A 10 ft eave sets the ceiling on door height before any frame change.
Drive-through
Matching openings at both ends avoid reversing, at the cost of usable wall.
Use
How a 20×40 RV Carport May Be Used
Height clearance
Interior height and door height are the deciding dimensions for tall vehicles.
Drive-through
Doors at both ends avoid reversing a trailer or coach.
Service space
Extra length beyond the vehicle allows for work and walk-around clearance.
Enclosed vs open
Open covers and enclosed buildings suit different climates and contents.
Planning
Footprint & Space Planning
Footprint
Width and length are chosen together: width is usually fixed by what has to fit side by side, length by how many bays are needed.
Height
Eave height is commonly the governing dimension here, because clearance for the tallest item sets the door and the wall.
Access
Where vehicles and people enter changes the whole interior layout, so access is settled before anything else.
Doors and openings
Opening width, height and position are specified with the supplier; they affect the frame and the wall bracing.
Site
Slope, drainage, access for delivery and erection, and the foundation are confirmed for the actual property.
Expansion
Extending along the length is usually simpler than changing the width later, which is worth deciding up front.
Similar sizes
Other Sizes for a RV Carport
20′ × 20′
400 sq ft
20′ × 60′
1,200 sq ft
30′ × 40′
1,200 sq ft
Related
Related Building Types
Example configuration — for planning purposes only.
FAQ
Common Questions
20 ft × 40 ft is 800 square feet of floor area before any interior partitions.
Length is usually adjusted in bay increments, and width is a larger design change. Both are confirmed with the supplier for the final design.
Site preparation, foundation and erection are commonly quoted separately from the building package. Confirm the scope of any quote you receive.
Compare nearby sizes
Related footprints for this building type
Each page works through one footprint for one building type.
Overview
A 20x40 rv carport planned as a coach bay with a working area kept for maintenance on the vehicle
This page is ordered around the working side, because a bench that is only reachable when the vehicle is out is not a bench.
The 20-foot width takes 1 service bay across, but the 40-foot length does not complete a full row once 8 feet of circulation is deducted — the depth is the binding dimension here.
Read this footprint through its span. 20 feet across is the fixed constraint; 40 feet of length is the negotiable one, and at 2 to 1 the building is long for its width, so movement runs front to back. Access, not area, is what makes a plan feel small once it is in use.
A 20 by 40 footprint is a clearly directional plan: 800 sq ft enclosed by 120 ft of wall, at a 2:1 length-to-width proportion. Along its 40 ft dimension it takes 1 run of service bays at 45 ft, leaving -5 ft over — the -5 ft is where the argument about this size actually happens. Owners who maintain their own coach need the working area to survive the vehicle being in the building. That is a width and wall-access decision made before the frame is ordered, not a fit-out decision made afterwards. Slab thickness and any structural provision are engineered for the vehicle weights involved.
This footprint is planned as a coach bay with a working area kept for maintenance on the vehicle. Compared with a 20 by 30 of the same width, the extra depth here adds run rather than reach: it buys about 1 service bays in line, and every position past the second is retrieved by moving what stands in front of it. Spent as a square 28 by 28 instead, the same 800 sq ft would stand 1 service bays across rather than 1, and would trade this plan's length for parallel access. That is the width-against-depth decision this footprint has already made. At this scale the building is usually operated by one or two people who know where everything is, so the plan can be loose and the doors matter more than the divisions. The longest internal travel on a 20 by 40 plan is about 45 ft corner to corner, and the shortest useful one is the 20 ft cross-run. For a a coach bay with a working area kept for maintenance on the vehicle that matters where rv service bay sits, because shortening the 20 ft run to serve it lengthens every trip along the 40 ft dimension. Site drainage at the door threshold decides where water goes when a large door opens.
Areas, perimeter, roof area, ridge height, slab volume and the service bay counts on this page are computed from the stored 20x40 record and this platform's planning module for the rv carport category.
Allocation
Dividing the floor for a coach bay with a working area kept for maintenance on the vehicle
The shelter pattern this footprint could equally be arranged for is shelter for one coach with nothing else expected to share the building: there is no walking strip, so the coach fills the building and any check on it happens outside. The vehicle line, a bench run with standing depth, and clear wall for storage that the vehicle does not block.
Because 32 feet clears the 12 feet this platform treats as usable, the end of the run is a room rather than a gap: 640 square feet for a bench and parts zone along one wall, positioned so it stays reachable with the coach inside. Set the openings before the interior, because the openings cannot move and the interior can.
Only 2 feet of width is spare, so there is no wall strip: anything set along a sidewall comes out of a service bay's clearance. Where the building sits on the site changes how much of this floor is genuinely reachable.
Compared with a 20 by 30 of the same width, the extra depth here adds run rather than reach: it buys about 1 service bays in line, and every position past the second is retrieved by moving what stands in front of it. Spent as a square 28 by 28 instead, the same 800 sq ft would stand 1 service bays across rather than 1, and would trade this plan's length for parallel access. That is the width-against-depth decision this footprint has already made. At this scale the building is usually operated by one or two people who know where everything is, so the plan can be loose and the doors matter more than the divisions. The longest internal travel on a 20 by 40 plan is about 45 ft corner to corner, and the shortest useful one is the 20 ft cross-run. For a a coach bay with a working area kept for maintenance on the vehicle that matters where rv service bay sits, because shortening the 20 ft run to serve it lengthens every trip along the 40 ft dimension. Site drainage at the door threshold decides where water goes when a large door opens. That movement pattern, not the 800-square-foot total, is what decides whether the leftover 32 feet is useful here.
Footprint arithmetic
The 20x40 footprint measured for a rv carport
Computed dimensional profile of a 20x40 rv carport
| Measure | Computed at this footprint |
|---|---|
| Floor area | 800 sq ft |
| Interior after a 2 ft wall strip | 16 × 36 ft (576 sq ft) |
| Proportion | 2 to 1 |
| Perimeter | 120 ft (150 ft per 1,000 sq ft of floor) |
| Wall carried against a square of the same area | +6% |
| Enclosed volume | 9,320 cu ft at a 10 ft eave and 13.3 ft ridge |
| Roof plane against floor | 843 sq ft (+5%) |
| Service bays planned | 1 across × 0 deep = 0 |
| Circulation and margin | 100% of the footprint |
| Widest clear opening planned | 12 ft on the 20 ft gable, 6 ft in a sidewall bay |
| Bay division | 4 bays at 10 ft (exact) |
Computed from the stored 20x40 record. The 2-foot wall strip, 4-foot corner margin and 4-foot pier allowance are this platform's planning conventions for reading a footprint; they are not code minimums or engineered clearances.
20 ft across takes 1 service bay and leaves 2 ft. Over 40 ft of run that slack becomes a continuous side aisle rather than 0 separate gaps.
The gable clears roughly 12 ft after corner framing: 0 openings at most. With one shallow rank the end wall is the whole access strategy.
40 ft is under one full 45-ft rank with circulation. 800 sq ft is small enough that the far end is still within reach of the main door.
40 ft divides exactly into 4 bays at 10 ft. Partitions, openings and lighting rows all land on the same 10-ft grid.
32 ft survives at the end of the run — 640 sq ft across the full width. That is a zone to name before the frame is ordered, not a leftover to discover after it.
How the 40-foot run can be divided
| Bays | Spacing | Division | What it means for the plan |
|---|---|---|---|
| 4 | 10 ft | Exact | 40 divides exactly by 10, so the frame line, the sidewall openings and any interior division can all land on the same grid. |
| 2 | 20 ft | Exact | 40 divides exactly by 20, so the frame line, the sidewall openings and any interior division can all land on the same grid. |
| 3 | 13.3 ft | Nearest even division | 3 bays works out at 13.3 ft, because 40 does not divide by 12; the odd bay usually goes at the end that carries the door. |
Bay divisions are arithmetic on the stored 40-foot length. Frame spacing for a specific building is set by the manufacturer's engineering, not by this table.
Usable area
How the 800 square feet divides at 20x40
Computed service bay fit for a 20x40 rv carport
| Measure | Computed at this footprint |
|---|---|
| Service bays across the 20-foot width | 1 at a 18-foot module |
| Leftover width | 2 ft (80 sq ft as a full-length strip) |
| Rows along the 40-foot length | 0 at a 45-foot module after 8 ft of circulation |
| Leftover depth | 32 ft (640 sq ft across the width) |
| Total service bays | 0 |
| Share of floor committed | 0% |
Module footprint used here is 18 by 45 feet, this platform's planning module for a rv carport. It is not a code minimum or an engineered clearance.
Example allocation of the 40-foot length — planning model, not survey data
| Zone | Length along the building | Computed area |
|---|---|---|
| Parking bays | 28.8 ft | 576 sq ft |
| Walk-around and door swing | 7.2 ft | 144 sq ft |
| Tools and seasonal storage | 4 ft | 80 sq ft |
Shares applied to the stored 40-foot length; areas computed against the 20-foot width.
Module footprints and allocation shares come from this platform's use typology and are published as example planning models. They are not recommendations and do not describe a majority of projects.
Configurations
Configuring 1 service bays at 20x40
At 20-foot nominal bays the structure works with the layout instead of against it: one service bay per bay line, walls free of awkward half-positions. Snow, wind and site exposure change what this shape costs to build long before the interior plan does.
One row deep keeps the layout honest — no aisle to protect, no rear zone to serve, and the full 40-foot length available along the wall. Fire separation, egress and occupancy are determined for the specific building and can reshape this plan entirely.
Extension is cheapest along the 40 ft dimension, where each added bay repeats work already framed; widening past 20 ft is a different frame rather than a longer one. Growing to 20 by 85 adds a 2th run of service bays — useful if the constraint is service bays rather than the -5 ft already spare at the far end.
Configured as a coach bay with a working area kept for maintenance on the vehicle, 20x40 is judged on whether the 0 service bays it holds match the operation, and on whether the 2 feet of spare width leaves the route this mode depends on.
- Does the work need one vehicle lane with roughly a bench depth left over beside it, or does it need a second lane that this 20-foot span cannot give?
- Is the 40-foot length being bought for depth, or for the repeated bays — three or four repeated frame bays, which sets a clear grain for partitions and rack lines?
- What is the vehicle's height with everything on the roof, plus a margin?
- Is there a straight approach long enough to park without shunting?
Bay division shown here is a planning module computed from the stored length. Actual bay spacing is set by the manufacturer's frame design for the building.
Height
Interior height for a 20x40 rv carport
The stored configuration carries a 10-foot eave and computes to 13.3 feet at the ridge on a 4:12 pitch — a 3.3-foot rise across 20 feet. Height is therefore not uniform, and the sidewall is the constraint. The mezzanine that is added afterwards is the change order that reprices the frame.
Height covers the coach and, where roof work is intended, safe access above it. Access provisions are engineered for the specific arrangement.
Clear height below purlins, bracing and lighting is lower than the eave height. The usable figure comes from the manufacturer's framing for the selected building.
Openings
Openings for 1 service bay across
Openings are the pinch point here. With 2 feet of spare width the gable cannot host 1 separate doors, so access is either shared or moved to the 40-foot sidewall. Storage expands until it meets a wall, so give it a wall on purpose.
The 20 ft ends and the 40 ft sides offer very different opening budgets: 20 ft of end wall has room for one wide opening or two modest ones, while 40 ft of side wall can carry several without the openings competing. On this plan the deciding factor is whether rv service bay or bench side width should be the first thing reached from the door.
Framed-opening sizes, headers and the structure around them are engineered for the specific building. Confirm every opening with the door supplier and the building manufacturer before ordering.
Cost drivers
Quantities that move the estimate at 20x40
No price appears on this page. The quantities that scale an estimate at 20x40 are 800 square feet of slab, 9.9 cubic yards of nominal concrete, 1,200 square feet of wall cladding and 843 square feet of roof cladding. Judge the plan by what has to happen on the worst day of the year, not on an average one.
Power, lighting and bench-side width are the additions over plain storage, and they are what turn the building into a working one.
- the height needed to clear a tall vehicle with a margin
- column spacing along the lane
- anchoring for a tall open structure
- the approach and pad the vehicle drives on
Comparison
What changes at adjacent footprints
Computed comparison of nearby footprints for a rv carport
| Footprint | Floor area | Service bays |
|---|---|---|
| 10x10 | 100 sq ft | 0 (0 x 0) |
| 10x12 | 120 sq ft | 0 (0 x 0) |
| 12x16 | 192 sq ft | 0 (0 x 0) |
| 10x20 | 200 sq ft | 0 (0 x 0) |
| 12x20 | 240 sq ft | 0 (0 x 0) |
Areas computed from each stored size record; service bay counts computed with the same 18 by 45 foot planning module.
- 10x10 holds the same 0 service bays but changes the leftover depth by -28 feet, which is where the difference is actually felt.
- 10x12 holds the same 0 service bays but changes the leftover depth by -24 feet, which is where the difference is actually felt.
- 12x16 holds the same 0 service bays but changes the leftover depth by -20 feet, which is where the difference is actually felt.
Nearby footprints read for a rv carport: exact change in area and in planning service bays
| Footprint | Area Δ | % Δ | Service bays at that footprint | What changes for this use |
|---|---|---|---|---|
| 25x30 | −50 sq ft | −6.2% | 0 (1 x 0) | Same service bay count on this planning module; the difference is circulation and stored depth, not capacity. |
| 24x36 | +64 sq ft | +8% | 0 (1 x 0) | Same service bay count on this planning module; the difference is circulation and stored depth, not capacity. |
| 18x40 | −80 sq ft | −10% | 0 (0 x 0) | Same service bay count on this planning module; the difference is circulation and stored depth, not capacity. |
| 20x45 | +100 sq ft | +12.5% | 0 (0 x 0) | Same service bay count on this planning module; the difference is circulation and stored depth, not capacity. |
Areas are arithmetic on two stored size records; service bay counts use this platform's 18 by 45 foot planning module and are not a capacity statement.
Because this footprint is planned as a coach bay with a working area kept for maintenance on the vehicle, the useful next reads are different from the ones a differently shaped rv carport suggests: rv service bay, bench side width, personnel door access.
Visualization
Reading the 20x40 footprint as a rv carport
FAQ
Questions about 20x40 rv carport projects
Take 2 ft off each wall as a working strip and the plan area drops from 800 to about 576 sq ft across 16 by 36 ft. Against that, 1 by 0 service bays occupy 0 sq ft and roughly 100% of the footprint stays as movement and margin. That circulation share is the number worth arguing about; the headline area is not.
The 20-ft gable takes an opening of about 12 ft clear after corner framing — 0 module-width openings. The 40-ft sidewall takes up to 1 spaced with piers, and those piers sit naturally on the 4-bay grid at 10 ft. Openings are planning geometry here; the sizes a specific building can actually carry come from the manufacturer's engineering for that frame.
One more bay at 10 ft adds 200 sq ft, 25% more floor, and keeps the clean division. It buys depth, not span: if the constraint is fitting things side by side, extra length does not solve it.
The width leaves 2 feet spare after 1 service bay. That margin absorbs wall storage and passing room. Width is the dimension that cannot be extended later.
Reserving 8 ft across the 20 ft dimension for movement leaves 12 ft of working width, which takes 1 service bays at 18 ft. Along 40 ft it takes 1 runs at 45 ft. That is 1 positions out of 800 sq ft, and the remainder is circulation, walls and the margin every plan needs. Whether that count is enough depends on is the workbench usable while the coach is parked, or only when it is gone. These are planning figures computed from the footprint, not a quoted layout.
Length here buys 0 rows and 2 nominal bays; width buys 1 position side by side. At this aspect ratio the building is already long for its span, so extra length adds depth rather than capacity.
In a building used for work, yes. It means short visits do not require operating the large door and its full opening cycle.
Enclosure one side at a time is the usual progression, ending at an RV garage Practically, the 40-foot dimension is the one that extends; the 20-foot span is fixed once the frames are set.
Methodology
How this page was produced
Sources and methodology
Find Steel Buildings dimensional records
Find Steel Buildings · Primary platform dataset · Tier 1 — code authority, standards body, primary dataset or manufacturer engineering
Supports: Stored nominal width, length, eave height, roof pitch and slab thickness for this subject.
International Building Code and International Residential Code
International Code Council · Model code · Tier 1 — code authority, standards body, primary dataset or manufacturer engineering
Supports: The framework of adopted codes and local amendments that decides permitting, separation and opening requirements. Cited as the governing framework, never as a local requirement.
- Dimensional figures: Width, length, eave height, roof pitch and nominal slab thickness come from this platform's stored record for the subject. Floor area, perimeter, wall area, roof area, ridge height and slab volume are computed from those inputs rather than transcribed.
- Service bay fit: Counts, leftover strips and per-module areas are computed from the stored 20x40 record against this platform's 18 by 45 foot planning module for the rv carport category, with 8 feet allowed for circulation. The module is editorial planning typology, not a code minimum or an engineered clearance.
- Allocation model: Zone shares come from this platform's use typology for vehicle shelter and parking and are applied arithmetically to the stored 40-foot length.
- Allocation and layout models: Layout splits are arithmetic on the stored footprint, published as example allocation models. They are not survey findings and do not describe what buyers most often choose.
- Clearance and opening guidance: Clearance and opening statements are planning guidance. Final dimensions depend on the selected door system, header detail and the manufacturer's engineering for the building.
Methodology notes
- Prices: No price figure appears on this page. Cost data is published on this platform only with a documented inclusion basis, a collection date and a named source.
Drawn to scale
Plans and dimensions
Every drawing below is generated from the exact dimensions for this building, so proportions and areas are accurate.
Continue your research
Related planning topics
Background reading on the questions this page raises. None of these pages sells anything.
Compare 20x40 rv carport configurations
Review the allocation models for this footprint side by side, then estimate the configuration you intend to build.