20x40 Steel Building, a Deep Single Bay for RV, Boat, or Long Storage
800 sq ft clear-span shell built long, not wide — starting at $13,500, delivered.
50-Year Paint Warranty, 50-Year Rust Perforation Warranty, 60-Year Structural Warranty, and Lifetime Warranty on Hardware — all transferable to the next property owner.
Get Your Customized Quote
- No obligation — we’ll send the price, not a salesperson to your door.
- Engineered drawings stamped for your state.
- 60-Year Limited Structural, 50-Year Limited Paint, 50-Year Limited Rust Perforation, and Lifetime Limited Hardware warranties.
- Delivered nationwide, all 50 states.
C-Channel Clear Span • 20’ Wide, 40’ Deep • 60yr Limited Structural Warranty • Nationwide Delivery
20x40 Steel Building Price
$13,500 and up
C-channel framing, 10’ eave height basis, standard snow and wind loads.
Included
- • Stamped, engineered building drawings for your state
- • All primary building components
- • Freight to your site
Not included
- • Doors and windows
- • Insulation
- • Concrete or foundation work
- • Erection
Building specs
- • Framing type: C-channel solid frame, 10-16 gauge steel
- • Roof / wall panels: 26-gauge and heavier available
- • Roof pitch: Up to 8/12
- • Coating: Galvalume AZ55 on all primary and secondary framing
- • Hardware: Stainless steel hardware with a neoprene washer
- • Trim package: Full trim package included
What moves the price
- • Eave height above the 10’ basis
- • Ground snow load above 35 psf
- • Wind load above 110 mph
- • Areas with high seismic activity
This is a starting price, not a binding quote — your exact number depends on your state’s code requirements, site conditions, and what the building has to carry. We confirm the real number with stamped engineering before you sign anything.
What a 20x40 Footprint Actually Looks Like
Drawn to scale from the same specification the price above comes from. Door, window and interior layout aren’t shown because every Northcraft building is engineered to your plan — what’s fixed at this size is the footprint, the clear span and the eave height.
What Fits in a 20x40 Footprint
800 square feet, clear span, no interior columns — the same 20-foot width as Northcraft’s other narrow-lot sizes, just twice as deep.
RV or Boat Storage Bay
40 feet of depth clears most Class A motorhomes and boats with a trailer, with room to walk the length of the load. The narrow 20-foot width keeps the footprint tight on a residential lot.
Long Workshop or Woodshop
800 square feet laid out end-to-end suits a shop that needs a long, uninterrupted work line — cabinet building, boat repair, or anything with long stock.
Vehicle Plus Trailer Storage
A daily-driver vehicle up front and a utility or equipment trailer behind it, both under one roof instead of parked outside.
Narrow-Lot Solution
20 feet of width fits lots and side yards a wider building can't — a common fix when a property's frontage or setbacks rule out a 30- or 40-foot-wide option.
Using a 20x40 as a Garage
800 square feet in a long, narrow footprint. Two vehicles fit in tandem down the 40-foot length, or one vehicle with a genuinely large shop area behind it rather than a corner of one.
The trade-off to understand: tandem parking means moving the front vehicle to get the back one out. If both need independent access, the width has to grow, not the length.
Two things worth settling before engineering rather than after, because both are far cheaper to change on paper:
- How you will get the back vehicle out. Tandem parking means moving the front one first. If both need independent access, plan a second door now rather than cutting one in later.
- Lighting down the length. A 40-foot narrow building is dark in the middle. Decide on windows or translucent panels before the panel layout is engineered.
What a 20x40 Costs Beyond the Building
$13,500 covers stamped engineering drawings, the building components and freight - not the concrete. 800 square feet in a 20-foot-wide strip is an easy pour to screed, because the crew can work across the narrow dimension from both sides without wading into wet concrete.
That convenience does not translate into a price we can publish. What actually decides it is your site: how level the pad already is, how far the trucks drive, and whether the approach lets a mixer get close to the far end of a 40-foot run.
Get local quotes for 800 square feet with thickened edges, and mention the building is 40 feet long so access to the far end is priced rather than assumed. Your stamped drawings include the anchor-bolt pattern and we send it straight to the contractor.
The other items priced separately: doors and windows, insulation, and erection.
What Extra Depth Costs on a 20x40
At 800 square feet, $13,500 works out to $16.88 per square foot — cheaper than both 20x24 ($21.88/sq ft) and 20x30 ($19.00/sq ft), because the fixed cost of engineering and endwall framing spreads across more floor as the 20-foot family gets longer. That pattern holds all the way up Northcraft’s list — longer almost always means cheaper per square foot, not more expensive.
The freight side of a 20x40 is the heaviest package in the 20-foot family, simply because there’s more steel in a 40-foot run than a 24- or 30-foot one. Foundation is priced separately from Northcraft’s price either way (see “What’s included” above), but it’s worth flagging to your contractor early that a slab this long and narrow behaves differently than a square one — see the FAQ below on control joints.
Width vs. Depth: 20x40 Against 30x40
Here’s a genuinely useful comparison: 20x40 and 30x40 share the same 40-foot length, differing only in width. 30x40 costs more in total ($17,300 versus $13,500) but runs cheaper per square foot ($14.42 versus $16.88), because the two endwalls — the fixed cost that doesn’t change with width — now cover 400 more square feet of floor. If your lot genuinely can’t take anything wider than 20 feet, that’s the real reason to stay here. If width isn’t the constraint, 30x40 is the more efficient building for the same length.
Backed By Real Warranties
YEAR LIMITED PAINT WARRANTY
YEAR LIMITED RUST PERFORATION WARRANTY
YEAR LIMITED STRUCTURAL WARRANTY
LIMITED HARDWARE WARRANTY
All four warranties are transferable to the next property owner. Every building ships with code-compliant stamped engineering for the delivery state.
* Warranty coverage is subject to applicable warranty terms, conditions, limitations, and exclusions. Complete warranty details are provided during the purchase process and included within the applicable purchase documentation.
Frequently Asked Questions
What does a 20x40 steel building cost?
Northcraft's published floor for a 20x40 is $13,500, delivered, at a 10-foot eave height with standard loads (ground snow to 35 lb, wind to 110 mph). That covers stamped engineering drawings, the building components, and freight — not doors, windows, insulation, concrete, or erection.
How much does a concrete slab cost for a 20x40 metal building?
Northcraft prices foundation work separately (that service is available — ask for it in your quote request) and won't publish a figure. 800 square feet in a 20-foot-wide strip is straightforward to screed, but what it costs depends on your site: how level the pad is, how far the trucks drive, and whether a mixer can reach the far end of a 40-foot run. Get local quotes for 800 square feet with thickened edges and mention the length so access is priced rather than assumed.
Is a 20x40 metal building the same as a 20x40 steel building?
In everyday use, yes — most buyers say "metal building" and "steel building" interchangeably, and we answer to both. The distinction worth caring about is the frame, not the word. A solid frame like the C-channel in a 20x40 is a different structure from a hollow tube frame, which is what most of the cheapest advertised carport-style buildings use. Two buildings can both be sold as a "20x40 metal building" and not be comparable products.
Will a 20x40 fit an RV or a boat?
Most Class A motorhomes and boats on a trailer fit within 40 feet of depth, with a few feet of clearance at the door end for maneuvering. If you're storing something longer than about 38 feet, tell us the exact length before ordering doors — clearance is a door-sizing question, not a building-length one.
Do I need a permit for a 20x40 steel building?
Most jurisdictions require a permit for a structure this size. We provide the stamped engineering drawings your local building department will ask for.
Can I customize the building, or is 20x40 a fixed size?
Every Northcraft building is fully customized to your exact specifications — this isn't a catalog of fixed sizes. Bring your own dimensions, door and window placement, and requirements, and we'll engineer to those specs instead of a preset.
What's included in the price, and what isn't?
Included: stamped engineered drawings for your state, every structural and panel component, and freight to your site. Not included: doors and windows, concrete or foundation work, and erection — priced separately; those services are available. For RV or boat storage, door height and width are the detail to get right early.
What loads does the $13,500 floor assume, and what raises it?
The floor is based on ground snow load up to 35 lb per square foot and wind speed up to 110 mph. Eave height above the 10-foot basis, higher snow or wind ratings, and high seismic activity all move the price. Tell us your zip code and we'll confirm your real number.
Can I erect a 20x40 myself?
It's a longer building than a 20x24 or 20x30, but still narrow and bolt-together, so it stays a realistic DIY project for an experienced crew with basic tools. Our buyers' guide covers what that actually involves.
How long does a 20x40 building take from order to delivery?
Typically 45-60 days from order to delivery, depending on engineering review and current production volume. Your estimator confirms a real date range once your drawings are finalized.
Does a long, narrow slab like 20x40 need anything different from a square one?
Foundation work is priced separately from Northcraft's building price — that service is available; ask for it in your quote request. It's worth knowing before you talk to a contractor that a long, narrow pour is generally more prone to cracking along its length than a square one of the same area, which is why many contractors add control joints at intervals down a slab this shape. Ask your foundation contractor how they plan to handle it for a 20-foot-wide, 40-foot-long pour specifically.
Get Your 20x40’ Customized Quote Today
Starting at $13,500, delivered and engineered for your state. No obligation.
Call: (888) 460-9294 | Email: Estimating@Northcraftsteel.com
Get Your Customized Quote