Floor plans for surveyors and valuers

Capturing height zones properly

In loft spaces and rooms with slopes, zoning decides the result. Capture the two-metre and one-metre lines in the room and calculate the zones individually rather than inferring them from the roof pitch.

Record where you measured and by what method. When a figure is later disputed, the question is never whether the formula is right but whether the inputs are evidenced.

• Measure height lines in the room, do not derive them
• Report raw area, factor and result separately per room
• Mark ancillary rooms as such
• Document measuring points and method

Derivation instead of a headline figure

The editor applies the German living-area factors room by room and shows raw area, factor applied and weighted area separately. That schedule can be attached as a PDF, so the calculation becomes part of the record.

Where you depart from the standard case — a balcony counted at more than a quarter, for instance — document the reasoning in the text. The regulation leaves discretion; unexplained discretion is attackable.

Preserving the state at a point in time

A report describes a condition at a date. Save the plan in the state your calculation rests on as a separate file — the JSON export contains the full geometry including the computed areas.

It is little effort and closes a familiar gap: if a floor area is argued about years later, you can evidence exactly which geometry the calculation was based on.