Plan a shed footprint, roof and openings

Set the footprint from the outside frame

Front width and depth describe the outside of the wall frame. They exclude cladding and roof overhangs. The floor area is the outside footprint, so usable interior space is smaller.

The front and back frames run the full width. The left and right frames fit between them. Their opening positions start at their own frame ends, measured from the left when you stand outside looking at that wall.

• Start with room for the largest item that must pass through the door.
• Set eave height for a gable or low-wall height for a single slope, from the floor datum to the top of the frame.
• Choose timber floor for an area-based floor-sheet estimate, or concrete slab for a bagged-mix and ready-mix supply estimate. Supporting structures and elevations above grade are separate.

Read the roof geometry

The gable ridge runs from front to back. For a single-slope roof, choose the slope direction: front to back, back to front, left to right or right to left. Each option names the low and high wall. The entered low-wall height stays the same when you switch direction; the high wall rises across the selected width or depth. The floor plan marks the low and high sides, and wall framing, 3D geometry and quantities follow the selection. Pitch is the rise for every 12 inches of horizontal run. The same horizontal overhang applies on all four sides.

Roof covering and sheathing estimates use the true sloped surface including those overhangs. Highest wall point refers to the wall profile above the floor. It excludes roof-member depth, finishes, foundation height and the extra rise beyond the high wall on a single-slope overhang.

Roof area = (width + 2 × overhang) × (depth + 2 × overhang) × √(1 + (pitch ÷ 12)²)

Place clear rough openings

Select Front, Right, Back or Left under Doors & windows, or select a wall in Floor plan. Add a door or window and enter the clear rough-opening width and height. Door openings start at floor level. Window bottom is the height from the floor to the clear opening.

The wall layout replaces common studs with the entered king studs, jack studs, header plies, sills and cripples. If support packs overlap or a header will not fit, the drawings and quantities stop until the dimensions are corrected.

Header depths and support counts begin with editable example values. They are not load calculations. Enter the specified framing detail for your project before treating the quantities as a takeoff.

Compare concrete by volume and cost per square foot

Choose the concrete slab floor option, then enter thickness and a concrete volume allowance. The estimate uses a uniform slab matching the outside shed footprint. It excludes thickened edges, footings and aprons. The concrete allowance is independent of the sheet-material allowance.

Bags are rounded up to whole bags using the finished yield. The general purpose, high strength and fast setting presets reference SAKRETE Canada 30 kg products, each with an approximate yield of 14 litres. Choose a custom yield for a different product. A different strength or setting time does not itself change the slab volume.

Ready-mix is rounded up to your entered order increment in cubic metres or cubic yards. A minimum billed volume changes the price calculation without adding concrete to the physical order. Delivery and short-load fees are entered as totals for the entire order. Confirm actual delivery minimums separately with the supplier.

Starting prices are illustrative CAD budget inputs: $9 per bag, $300 per cubic metre and $250 for ready-mix delivery, with other fees and minimums starting at zero. They are not local quotes. Replace all applicable values with supplier prices. A blank price is unknown; zero means no charge.

Slab volume (cu ft) = footprint (sq ft) × thickness (in) ÷ 12
Volume to allow for = slab volume × (1 + allowance ÷ 100)
Bags = round up (volume in litres ÷ finished litres per bag)
Ready-mix supply cost = max(rounded order, minimum billed volume) × unit price + fees
Supply cost per sq ft = total concrete supply cost ÷ footprint

Use the right quantity for the next step

The sheet counts are 4×8 area equivalents, not a numbered sheet cutting layout. Material coverage, seams, laps, defects, orientation and available lengths can change the purchase.

Reveal wall framing in 3D to inspect the wall layout; floor joists and roof members are not shown. Floor plan and all four wall elevations are included when you print. Save plan downloads an editable UC shed JSON file; Open plan restores it later.