Creating a floor plan for an attic apartment

Record heights, not just footprints

In every room with a slope, measure two lines: where the clear height reaches two metres, and where it drops to one metre. Those two lines divide the room into three zones — counted in full, counted at half, not counted.

Note the knee wall as well, that is the height of the external wall up to the roof line. A knee wall of 1.20 m changes the usable area of a room more than any furniture arrangement, and it tells viewers immediately why a sloped room still takes a wardrobe.

• Mark the two-metre and one-metre lines inside the room
• Note the knee wall height for each external wall
• Draw dormers and roof windows differently
• Show countable area next to the raw footprint

What the plan additionally has to show

Dormers create standing height exactly where there would otherwise be none, so they add value. Draw each dormer with its width. Roof windows, by contrast, bring light but no height — a difference that belongs on the plan because it decides usability.

Equally important: the staircase and the clear height above it. A stair you have to duck under is a viewing topic. A plan that notes the height there prevents an unpleasant surprise.

Make the calculation transparent

State both numbers in the listing: the raw footprint and the area weighted under the German rules. The editor applies the factors per room and shows raw area, factor and result separately, so every line stays checkable.

That transparency does not hurt the sale. Buyers distrust a round number with no derivation far more than a smaller number with a clean calculation — and so do valuers.