Shed planning · Guide 3 of 5 · 5 min readUpdated
Plan shed roof framing, soffits and fascia
Follow the roof direction into rafters, ties, overhang framing, fascia and soffit quantities, then check the roof schedule and 3D layers.
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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. Set eave overhangs at the level roof edges and rake overhangs at the sloping edges separately. Both are horizontal measurements to the outside roof edge; they rotate with the selected slope direction.
Roof covering and sheathing estimates use the true sloped surface including those overhangs. Highest wall point refers to the wall profile above the floor. The separate Top of roof deck figure adds the entered rafter and sheathing depth, plus any high-side overhang rise. Foundation height and roof-covering thickness remain additional.
Roof area = (run across slope + 2 × eave overhang) × (length along eave + 2 × rake overhang) × √(1 + (pitch ÷ 12)²)
Keep units consistent; divide square inches by 144 to get square feet. This geometry does not size rafters, trusses, ties, connections or foundations.
Lay out the roof framing and trim
Choose rafter size and spacing, sheathing thickness, subfascia depth, fascia finish and soffit layout. These begin as editable examples, not calculated structural sizes. The gable assembly has paired rafters, a ridge board and one low tie at each interior pair; the end rafters sit over the framed gable walls. The single-slope assembly runs full rafters between the low and high walls, following any of the four directions.
The rake overhang uses fly rafters and 2×4 ladder blocks on flat, with spacing measured horizontally along the rake. Eave blocking can be included between rafters. Enter the construction detail specified for the project; this schematic does not design an overhang cantilever, a structural ridge beam, trusses, storage loading or connections.
The wall profile is the underside reference for full-depth rafter blanks. Member depth is added above that profile. Birdsmouths, bearing seats, ridge pockets and other connection cuts are not shown or deducted; actual bearing details change the finished roof elevation. Gross rafter blanks include the extra stock needed for plumb ends. Member quantities exclude spare lumber and stock-length waste.
Fascia covers both eaves and sloping rakes. Choose boxed eaves with sloped rakes, soffits that follow the roof, or open eaves. Boxed coverage includes corner returns and, on a single-slope high eave, an outer closure below the fascia so the soffit stays below the uncut rafters. Wall receiver/backing, roof-edge flashing and ridge-cap coverage are listed separately. Panel backing, seams, trim profiles and ventilation openings need a product-specific detail.
Use Roof framing or All framing under 3D layers to expose the members. Roof plan shows their orientation; expand Rafter cross-section to see the height reference. Roof member schedule groups individual pieces by stock size and gross blank length. Soffit area is coverage, not a vent free-area calculation.
Read roof members before ordering stock
Use the Roof plan and Roof section to match member marks to the schedule. Rafters, ties, ridge board, blocking, ladder blocks and subfascia have different roles. The listed blank lengths include the model’s end-cut allowance; they do not choose a connection or approve a span.
The materials budget combines compatible wall and roof lumber by actual size and allocates those blanks to stock. A long rafter that exceeds every enabled stock length remains a separate item requiring a quote. Do not treat it as permission to splice that rafter.
Keep roof surfaces and edge trim distinct
Roof sheathing and covering follow the sloped surface including overhangs. Soffit quantities cover the selected underside areas. Fascia and edge flashing use their own edge lengths, with the surface allowance applied to the appropriate quantities.
On a single slope, high-side flashing is a separate row and that edge is removed from the other-edge flashing total. Roof insulation follows the roof inside the wall footprint, so it excludes overhangs. These quantities describe different surfaces and should not be copied interchangeably.
Review the same orientation in every view
Floor plan and Roof plan put Front at the bottom and Right at the right. The 3D side labels follow the model. Use Plan orientation for a top-down comparison, or Fit view to return to perspective. Change 3D layers to exposed roof framing or all framing to see beneath the finish.
After changing pitch, wall depth or slope direction, recheck all four wall elevations, rafter direction, low and high edges, overhangs, openings and unpriced material rows. Save the revised project and print its roof schedule with the drawings.
Price roof and wall stock together
Choose sizes, ties, bearing, bracing, ventilation and connections from the required construction detail. The model is a layout and quantity aid.