Build a shed ramp by planning the load and slope first, then designing stable supports, a secure connection and a slip-resistant surface. The right ramp depends on what will use it: a wheelbarrow, a riding mower and a person using a wheelchair have different requirements.
This guide covers layout and construction decisions, not a universal lumber schedule. Preserve safe access to the doors and drainage around the shed, and have the structural details checked for your equipment and site.
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Decide what the ramp must carry
List the heaviest equipment, attachments, cargo and people that may be on the ramp together. Include concentrated wheel loads rather than considering only total weight. Measure equipment width, wheel track, wheelbase and ground clearance.
For powered equipment, read the exact model’s manual for ramp use, maximum permitted slope and safe loading procedure. Limits for mowing hills are not necessarily loading-ramp limits. A published example for another machine cannot establish safety for yours. Toro’s loading guidance illustrates why ramp width, slope and clearance at the transition matter.
Confirm the shed floor can support the same equipment. A strong ramp cannot compensate for an inadequate floor or narrow doorway.
Measure the rise and calculate the horizontal run
Rise is the vertical height from the finished lower landing to the upper ramp surface. Run is horizontal distance—not the sloping board length. Measure after deciding the lower support elevation.
- Slope as a ratio: rise : horizontal run.
- Slope percentage: rise ÷ run × 100.
- Horizontal run at a 1:n ratio: rise × n.
- Sloping length: square root of (rise squared + run squared).
Geometry example: a 12-inch rise at 1:12 needs 144 inches (12 feet) of horizontal run. The sloping length is about 144.5 inches, before detailing bearings, connections and landings. The slope is approximately 8.3%, or 4.8 degrees. A percentage and an angle in degrees are not interchangeable.
This example explains the math; it does not approve that slope for your equipment or establish a complete accessible ramp. Allow extra space for approach, turning and door operation.
Equipment ramps and accessible ramps are not interchangeable
If someone needs the ramp for wheelchair or other mobility access, plan a complete accessible route. The U.S. Access Board’s ADA standards address running slope, cross slope, clear width, landings, handrails and edge protection. A 1:12 maximum running slope is a familiar requirement in applicable designs, but meeting that ratio alone does not make a ramp compliant.
Whether those standards or other residential requirements apply depends on the property and use. Confirm with the local authority or an accessibility professional. Do not treat a short, steep lawn-equipment ramp as suitable for people simply because it reaches the doorway.
Plan width, door clearance and transitions
Provide usable width for the equipment plus a suitable operating margin. Check handles, mower decks and attachments, not just tire spacing. A full-width surface may be required by the machine manufacturer; two narrow tracks are not a universal substitute.
At the top, verify that doors can swing without scraping and that the threshold does not catch small wheels or mower components. At the bottom, avoid an abrupt lip or soft patch that stops wheels. Check breakover clearance where the ramp meets the shed; a mower can ground out even if the overall incline seems gentle.
Review the opening alongside our shed door guide. Do not remove a structural threshold or compromise weather protection merely to make the ramp fit.
Give the ramp a stable, draining base
Ramp supports must transfer loads to suitable ground without sinking, sliding or tipping. Bare loose soil is not a reliable bearing surface. Depending on the design and local conditions, supports may use a prepared aggregate base, concrete bearing or footings.
Account for frost movement, settlement and runoff. A ramp tied to a stable shed can still move at its lower end if the foundation is inadequate. Keep water from being directed into the doorway and avoid trapping wet soil against timber.
Use our foundation guide for planning context, not as a ramp footing schedule. Before digging in the U.S., contact 811 and follow the local response and safe-digging process.
Choose framing and decking for the actual loads
Joist or stringer size, spacing, span, grade and connections work together. A generic 12–16-inch spacing recommendation does not establish capacity for a mower, loaded cart or wheelchair. Use a tested manufactured ramp or a design checked for the expected loads and outdoor exposure.
Select timber treatment for its service conditions. “Pressure treated” does not mean every board is suitable for ground contact. Consult the treatment label and the AWPA Use Category System. Protect cut ends as directed by the treatment supplier.
Choose decking thickness and support spacing together. Exterior plywood must be suitable for the intended exposure and protected as specified; an exterior adhesive rating alone does not make exposed wood immune to decay. Do not reduce a support to a fragile thin tip just to achieve the ramp angle.
Use connectors and fasteners approved for the structural role, treatment chemistry and environment. Ordinary drywall screws are not structural ramp connectors. Simpson Strong-Tie’s corrosion guidance explains why compatible materials matter.
Secure the ramp against movement
A ramp should not simply rest loosely at the doorway, even for walking. Design positive support and restraint against sliding, lifting or separating. If attached to the shed, connect to sound structural framing using the specified hardware—not siding, trim or a weak threshold.
A freestanding or removable ramp needs its own stable supports and secure retention during use. Follow the retention instructions for a manufactured ramp. Do not rely on friction, a few improvised screws or the ramp’s weight to keep it in place.
Coordinate the attachment with the shed’s anchoring and weatherproofing. Flash penetrations and avoid details that collect water against the floor rim.
This construction video is an example, not a verified capacity rating or a complete design for your ramp.
Build, inspect and use the ramp safely
- Confirm the layout, loads, supports, connections and material schedule before cutting.
- Prepare stable bearing and check the finished elevations and drainage.
- Assemble the designed supports and framing, keeping the ramp square and avoiding unwanted side slope.
- Install decking and connectors with the required fasteners, edge distances and spacing.
- Add a suitable slip-resistant surface and any designed edge protection, guards or handrails.
- Inspect the entire assembly and resolve movement, sharp edges, gaps or drainage problems before use.
Do not test an uncertain ramp by driving heavy equipment onto it. Have its capacity confirmed first. Follow the machine manual for direction of travel and operating procedure; keep bystanders clear and do not turn on the ramp.
Traction and maintenance matter
Rain, algae, mud, leaves and ice can make a ramp slippery. Use an outdoor slip-resistant treatment compatible with the deck and wheel type. A coating or grip strip cannot make an excessively steep or unstable ramp safe.
Inspect for loose fasteners, decay, damaged decking, worn traction, erosion and changing alignment. Recheck the top attachment and lower bearing after severe weather. Keep debris clear and avoid use when the surface is unsafe.
For recurring movement or rotting wood, investigate the cause before replacing a few screws. Our shed repair checklist can help organize the work.
Shed ramp questions
How long should my ramp be?
Start with the measured rise and a slope appropriate for the intended user or equipment. Calculate the horizontal run, then allow for landings and transitions. If the available space is insufficient, change the layout rather than automatically making the ramp steeper.
Can I use a portable ramp?
Yes, if it has documented capacity, suitable dimensions, compatible bearing and secure retention for the application. Check storage, weather exposure and the equipment manufacturer’s requirements.
How much will it cost?
Price the full design: foundation preparation, treated framing, decking, connectors, traction, protection and labor. A short ramp with difficult access or heavy loads can require more work than its surface area suggests.
Include access in the shed plan
Plan the ramp before finalizing the shed’s floor height, doorway and site layout. Start with our shed construction guide. You can also explore Ryan’s Shed Plans as a paid planning resource. Check the package contents; purchased plans do not replace structural design, equipment instructions or applicable accessibility requirements.
Shed ramp length calculator: worked examples
Use the measured vertical rise and horizontal run to compare ramp layouts. The horizontal run is measured level along the ground; it is not the same as the sloping ramp length.
- Slope percentage = rise ÷ horizontal run × 100
- Ramp angle = arctangent(rise ÷ run)
- Horizontal run for a 1:n ratio = rise × n
- Sloping ramp length = √(rise² + run²)
These calculations describe geometry only. Add any required bearings, landings and transition details, and verify the final ramp structure and slope for the intended equipment or user.
Ramp length and angle examples
| Rise | Horizontal run | Slope | Approx. angle | Sloping length |
|---|---|---|---|---|
| 6 in. | 72 in. (6 ft.) | 8.3% / 1:12 | 4.8° | 72.2 in. |
| 8 in. | 96 in. (8 ft.) | 8.3% / 1:12 | 4.8° | 96.3 in. |
| 10 in. | 80 in. (6 ft. 8 in.) | 12.5% / 1:8 | 7.1° | 80.6 in. |
| 12 in. | 144 in. (12 ft.) | 8.3% / 1:12 | 4.8° | 144.5 in. |
A 1:12 example makes the math easy to see, but it does not automatically make a ramp suitable for a riding mower, wheelchair or other use. For mobility access, review the complete U.S. Access Board standards, including clear width, landings, cross slope, handrails and edge protection.
How to choose a shed ramp angle
The best shed ramp angle is the shallowest practical angle that works with the site and intended user. A steeper ramp saves space but increases traction demands, transition problems and the force required to move equipment. A longer ramp requires more material and stable support over a greater distance.
If the available run is too short, consider changing the doorway location, lowering the shed floor during the design stage, adjusting the approach grade where permitted, or using a properly rated manufactured solution. Do not simply make the ramp steeper without confirming that it remains suitable.
Shed ramp planning for a riding lawn mower
Measure the mower at its widest fixed point, including the deck and attachments, and compare it with the clear door opening. Record wheel track, wheelbase, operating weight, attachment weight and ground clearance. The ramp must resist concentrated wheel loads, not merely the mower’s total weight spread evenly across the deck.
Prevent the mower from bottoming out
A mower can scrape where the ramp meets the shed even when the main slope seems reasonable. Use a straightedge or side-view sketch to compare the mower wheelbase and lowest point with both transitions. Never remove a structural threshold or weaken the floor rim for clearance. Coordinate the opening with the shed-door guide and confirm the shed floor can carry the equipment.
What is a good ramp slope for a riding mower?
There is no single safe slope for every mower. Follow the exact manufacturer’s loading instructions and check width, traction, wheelbase, ground clearance, total load and transition geometry. Hill-mowing limits are not necessarily loading-ramp limits.
Is ramp length the same as horizontal run?
No. Horizontal run is measured level along the ground. Ramp length follows the sloping surface and is slightly longer. Mixing the two measurements produces an incorrect slope.
Can a shed ramp rest directly on soil?
Loose or wet soil can settle, erode and allow the ramp to move. Use a designed bearing condition appropriate for the soil, climate and loads, while directing water away from the doorway. See the shed-foundation guide and anchoring guide for related planning considerations.