Garage & Shed Design Software - Floor Plans to Framed Walls
Design your own garage, shed, workshop, or cabin from the floor plan up: draw the layout to exact dimensions and the software builds the framed walls from it, with floor joist layouts, automatic spans, and a blueprint for every wall. Add roofs on top, see the siding and trim on the finished structure, and export the wall blueprints, cut list, and material list for the build. One tool from floor plan layout to framed structure.
How to Use This Tool
Draw the floor plan layout
Lay out the perimeter of the garage, shed, cabin, or addition to exact dimensions. Rectangles, L-shapes, and custom footprints all work - this floor plan drives everything that follows.
Choose joists and spacing
Select 2x6, 2x8, or 2x10 joists at 12, 16, or 24 inches on center. The tool fills in the joist layout, checks each joist against its allowable span, and flags anything that needs a beam or a bigger member.
Add beams where spans demand
For floors wider than one joist span, drop in a center beam and the joist layout re-frames around it automatically.
Raise the walls and add the roof
The walls frame up from the floor plan layout, and you can add roofs over the structure and see the siding and trim on the finished building - the whole garage or shed takes shape from the one plan.
Export the wall blueprints and cut list
Generate the framing plan as a blueprint PDF - including a blueprint for every wall - plus a complete cut list with every joist, rim board, and beam length, ready for the lumberyard or a permit packet.
Floor framing math
A floor frame is counted the same way as a deck frame: joist count from width over spacing, rim joists along the joist ends, and sheathing off the area. The one extra check is span - residential floors carry 40 psf live load, and each joist size has a hard limit on how far it can reach at a given spacing before you need a beam.
floor area = length x width
wall length total = perimeter = 2 x (length + width)
joist count = (floor width / spacing) + 1
sheathing sheets = round up(floor area / 32 sq ft per 4x8 sheet)
Worked example: a 12 by 16 foot shed floor
- Footprint: 12 feet by 16 feet, so 192 square feet of floor and 56 feet of perimeter wall above it. Joists run across the 12-foot dimension.
- Span check: at 40 psf live load, a #2 SPF 2x8 at 16 inches on center is good to roughly 11 feet 6 inches - short of the 12-foot span - so the tool flags it. Step up to 2x10 at 16 on center, or keep 2x8 and add a center beam.
- Joists with 2x10 at 16 on center: 16 feet is 192 inches, 192 / 16 = 12 spaces, plus 1 = 13 joists, plus two 16-foot rim joists along the ends.
- Sheathing: 192 / 32 = 6 sheets of 3/4 inch tongue-and-groove plywood, laid perpendicular to the joists with end joints staggered.
- Export the blueprint PDF and cut list: 13 joists at 12 feet, 2 rims at 16 feet, 6 sheets - a complete lumberyard order from one drawing.
Frequently Asked Questions
How far can a 2x8 floor joist span?
At the standard 40 psf residential live load, a #2 spruce-pine-fir 2x8 spans roughly 11 feet 6 inches at 16 inches on center and about 12 feet 6 inches at 12 on center; southern pine goes farther. Sleeping rooms rated at 30 psf gain a foot or so. These come from IRC Table R502.3.1 - verify against your adopted code, since species and grade shift the numbers.
Should floor joists be 16 or 24 inches on center?
16 inches on center is the residential default: it suits 3/4 inch subfloor, matches 4x8 sheathing layout, and gives a stiffer floor. 24 on center saves a few joists but shortens the allowable span, requires thicker subfloor to avoid bounce, and rules out some finish floors like ceramic tile. For sheds and workshops 24 is often fine; for living space, stay at 16 or tighter.
How many floor joists do I need for a 16-foot long floor?
Divide the length the joists are spread along by the spacing and add one. A floor 16 feet long framed at 16 inches on center takes 192 / 16 + 1 = 13 joists, plus rim joists capping both ends. At 12 inches on center it is 17; at 24, 9. Double joists under parallel partition walls and around floor openings like stair wells.
Can I use this to design a shed or garage floor?
Yes - sheds, garages, workshops, cabins, and house additions are exactly what it is built for. Draw the footprint, pick 2x6, 2x8, or 2x10 joists, and the tool frames the floor, checks every span, and exports a blueprint PDF with a full cut list. For garages with a slab-on-grade floor you skip the joist system, but the tool still lays out the plan and wall lines.
Can I design a whole garage or shed with this - walls and roof included?
Yes. The floor plan layout is the starting point: the walls frame up from it automatically, you add roofs over the structure, and the finished building shows its siding and trim. Every wall gets its own framing blueprint, so a complete garage or shed design comes out as a buildable drawing set rather than just a floor sketch. For a single wall in isolation, the wall builder covers that.
Does it generate wall blueprints from the floor plan?
Every wall in the plan gets a blueprint with its framing laid out, alongside the floor framing plan, the cut list, and the material list. That is the practical difference from typical floor plan software: the output is not a room-layout picture, it is the drawing set a framer works from - which is why it suits garages, sheds, and workshops where you are the one building it.
What size beam do I need under floor joists?
It depends on the tributary width the beam carries - half the joist span on each side - and the distance between support posts. A built-up triple 2x10 typically carries a residential floor with posts around 7 to 8 feet apart at moderate tributary widths; longer spans call for a 2x12 build-up, LVL, or steel. Size it from IRC girder tables or an engineer, and land splices over posts.
Do I need blocking between floor joists?
The IRC requires lateral restraint at joist ends - usually the rim joist does that job - and full-depth blocking or bridging at intervals for deep joists (2x12 and larger, and any joist deeper than 6 times its thickness). Many framers block mid-span on 2x10 floors anyway to stiffen the floor and cut bounce. Blocking rows show up on the framing plan and in the exported cut list.