Cut list

Load a PDF or image of the roof plan, set its scale from a known dimension, then trace the planes over it. Drawings stay in this browser; the traced planes are saved with the job.

Trace a plane

Click round the plane's corners, starting with the eave, over a drawing or on the blank grid. Snapping uses the options under the plan. While tracing, the box under the plan takes a length and angle (from the grid, the previous line or an edge you pick) to place each point exactly. Type a length and press Enter to place the next corner exactly that far along. Backspace removes the last corner; Enter or clicking the first corner finishes; Esc cancels.

Add to roof

Enter plan dimensions to the roof outline (fascia line), not the walls. All planes share one grid: X to the right, Y up the page, in mm.

No planes yet. Add a roof shape above, or a blank plane and type its corners.

Walls are worked out from the whole roof outline, set in by each edge’s own overhang, so they meet at every corner, inside corners at valleys included. Refit all walls after changing the roof, or to close up walls added before this.

Corners (along the wall, height)

Doors and windows

Positions are measured along the wall from its left end, and up from the bottom of the wall; for a diamond, from the corner of the box around it. Flashings go round each opening wherever cladding runs alongside it: a head, two jambs (corner flashings), and a sill only if there is cladding below; a diamond gets a trim on each raked side. A sheet fully blocked by a door or window is split above and below; a sheet partly blocked is notched.

Overhangs are in plan, from the wall out to the fascia and barge. They draw a faint wall line inside the plane so you can see what sits over the wall and what hangs past it. If the dimensions you typed are to the wall, switch "Dimensions are to" and the roof outline grows by the overhangs, so the sheet lengths follow.

Sheet set-out

Sheets are laid out in full widths both ways from the set-out point, so any part-width sheets fall at the ends. Set out from the corner where a hip or valley meets the eave or ridge to start that cut with a full sheet. Midway between two corners with a sheet centred on the point gives a symmetrical plane, so the cuts on the left and right match — use the two eave corners of a pyramid or hip end. Centring a sheet on a hip end's apex makes the two sides mirror each other. You can also use the Set-out tool under the plan and click a corner. Left and right are as seen standing at the sheet direction edge looking up the roof.

Corners and edges

Openings (skylights, chimneys, vents)

Rectangles in plan, same grid. A sheet fully blocked is split into two sheets, above and below the opening; a sheet only partly blocked stays full length and is notched. Tick "stops water" for anything water cannot run past, like a chimney or a skylight, and the cut list lists the flashing dimensions around it.

What it is	X	Y	Width	Depth	Stops water

Size Blank 800 × 800 Whirlybird (400 × 400) Vent pipe (200 × 200) Skylight 600 × 600 Skylight 900 × 900 Skylight 1200 × 600 Chimney 600 × 600 Chimney 900 × 600 Chimney 1200 × 900 Add opening

Parapet walls

For a roof that stops against walls standing up past it. Tick the edges that run into a parapet: an edge running up the slope becomes a side wall (sidewall flashing), the top edge a headwall, and a low edge a box gutter. Where the eave hangs past the wall, the bottom of each side wall becomes a short barge. The parapet walls are added to the walls list (not clad) and show in 3D, with their capping in the flashings.

Wall thickness Parapet above roof Barge past wall Ticked edges are drawn toThe inside of the wallThe outside of the wall

Set parapet edges Not parapet walls

Step out (kick eave)

Carries the roof on past the eave at a flatter pitch, like a lapa kick or bellcast eave. Its sides follow the hips, valleys and barges straight on out, so step outs on neighbouring planes meet. With a drop, it becomes a separate lower skirt set below the eave instead.

Distance out Pitch ° Drop at the step

Add toEvery eave of this roofThis plane's eaves only Add step out

Add a split level (change of pitch)

Cuts this plane into a lower and an upper part along a line parallel to its sheet direction edge, with a split level line between them. The lower part keeps this plane's pitch.

Distance up Upper pitch ° Apply toThis planeEvery plane with an eave Split

Distance up is in plan (off the drawing), measured square from the sheet direction edge to the split level line. For a hipped roof that changes pitch all round, use "Every plane with an eave" so the hips line up.

Curved sheets

Crimp-curved sheets for this plane. The straight length B is worked out from the plane; the rest comes from the curve you set here.

Curve None – straight sheets Bullnose at the eave (standard crank) Concave at the eave (reverse crank) Cranked over the ridge (standard crank) Arched – whole plane curved Radius

Angle ° Tail A

Crown at Curves the other way (reverse crank)

Add a dormer

Sits the dormer on this plane, cuts the hole for it, and adds its roof planes with the valleys worked out. Sizes are in plan except the wall height.

TypeGable (doghouse)HippedShed Width Along the eave

Up from the eave Wall height Dormer pitch ° Name Add dormer

Width is across the slope to the dormer's outsides, "along the eave" is from the start of the sheets, and "up from the eave" is to the dormer's front wall. Wall height is the vertical height of the front wall above the roof surface. A shed dormer needs a flatter pitch than this plane.

Add a wing (joins this plane with valleys)

For a section that meets this plane at the same height. The valleys are cut into this plane and the wing planes are added for you. Measure the offset along the edge from its first corner.

On edge Offset from corner

Wing width Sticks out by Pitch °

Outer endGable (barge)Hipped Name Add wing

Width is measured along this plane's eave, to the wing's fascia lines. "Sticks out by" is from this eave line to the wing's end fascia.