A loft conversion lives or dies on two things a plan has to get right: how much of the floor has real standing headroom, and where the new stairs land. Draw those to scale early and you avoid the classic loft mistakes - a bed shoved under a slope, or a staircase that eats the room below. This guide shows how to draw a loft conversion floor plan on your iPhone or iPad, mark the reduced-headroom line honestly, and export clean drawings for quotes and building control.
What a loft plan has to show
A loft is not a plain rectangle of usable space - the roof slopes in at the eaves, so a chunk of the footprint is too low to stand in. A good loft plan makes that explicit and marks the pieces a builder and a building-control officer look for:
- The reduced-headroom line - where the ceiling drops below usable standing height under the slope.
- The stairs - position, direction and the headroom over them.
- The dormer - the flat-ceiling patch that gains you standing room and often houses the stairwell or ensuite.
- Rooflights, the escape window and any ensuite, with the usable area calculated.
As a rough guide, a loft is generally considered habitable where the ceiling is at least about 2.4 m at the ridge, with a common target of keeping at least half the floor area above roughly 1.9 m of headroom. Check the current building regulations for your project - but either way, the plan needs to show where that line falls.
Capture the loft (and the floor below)
Start with an accurate shell. On a Pro device with LiDAR, scan the loft and RoomPlot detects the walls and openings automatically; on any iPhone or iPad you can Draw Manually from a room-shape template and type your measured lengths, with snapping and the grid keeping it square. Because a loft sits above the storey below, add it as a new floor in the same project and capture the floor beneath too - RoomPlot keeps every level in one project so you can line the new stairs up with the room they rise from. For the full multi-storey workflow, see our guide to the multi-floor floor plan.
Mark the headroom line
This is the detail that makes a loft plan trustworthy. Use the Reduced Headroom symbol from the Real Estate set to draw the line where the slope crosses your headroom threshold, so the full-height zone reads clearly against the low eaves. Add a Ceiling Height tag at the ridge and a couple of dimensions, and the plan tells anyone reading it exactly how much real standing space the conversion delivers - not just its footprint.
Tip. Put the bed, wardrobes and the desk where the ceiling is lowest, and keep the full-height zone for standing and circulation. A wardrobe under a 1.2 m slope is dead space made useful - the plan is where you prove it works before a joiner builds it.
Fit the stairs, the dormer and the ensuite
With the headroom mapped, place the fixed elements. Drop the stairs from the Stairs set - Straight, Quarter Landing, Double Winder or Spiral, each drawn with real geometry - and position them under the ridge or the dormer where headroom allows, then check they land sensibly on the floor below. Add the dormer or rooflights as openings, partition off an ensuite if there is room, and use multi-select to nudge a group of elements together if the layout shifts. Because the whole plan is editable, trying a second stair position is a two-minute job, not a redraw.
Export for building regs and quotes
When the layout is set, export it. A single-page PDF or PNG is enough for an early quote; the multi-page branded Report PDF adds a cover, per-floor plans, a room-area summary and an automatic symbol legend - a tidy package for a client or a builder. Need it as editable CAD for an architect or structural engineer working up the building-regs drawings? Export DXF and it opens in any CAD package or viewer. RoomPlot draws the plan; your architect adds the sections and structural details on top of a base that is already accurate and to scale.
Planning the conversion end to end? Read how to create a floor plan for planning permission, or browse the full set of RoomPlot guides, then scan your loft and map the headroom today.