Replacement work is rarely a clean sheet. The old basin may hide an uneven wall, a cabinet may have been altered on site, and the drain can sit somewhere the original drawing never showed. A useful survey records the room as it is, not as the team assumes it should be.
Start with the opening, not the old product
Measure the available width, depth, and height at several points. Walls and cabinet sides are not always parallel. Record the smallest usable dimension and note tile trims, mirror edges, doors, and drawers that restrict the new basin.
Photograph the tape or laser reading in the same frame as the measured location. A page of numbers without location photos is easy to misread once the survey team has left the site.
Map the plumbing separately
Record the drain center from two fixed reference edges, then note pipe diameter, trap direction, water outlets, and shutoff access. Do not assume a centered bowl means centered plumbing.
If pipes can move, state who owns that work and when it will happen. If they cannot move, the basin drawing and cabinet layout must respect the existing points.
Check the cabinet from the inside
Open every drawer and door. Measure internal rails, drawer boxes, braces, hinges, and the clear route for the trap. An outside cabinet dimension does not reveal these conflicts.
For a basin that sits on or integrates with a vanity, compare the survey with the technical support drawing before approving the size.
Record wall and floor conditions
Use a straightedge where the basin or backsplash meets the wall. Gaps, bowed tiles, and thick grout lines can affect fit and sealant joints. Note whether finishes will stay or be replaced.
Also check access from delivery point to bathroom. A long integrated top may fit the room but not the lift, corridor turn, or doorway.
Turn the survey into one marked drawing
Combine dimensions, photos, plumbing points, and site notes in one dated record. Mark which dimensions are verified, which are estimates, and which require contractor confirmation.
When a non-standard size is needed, send this record with the inquiry for custom sizes. It gives the supplier a better starting point than a reference photo alone.
Measure once more before production
Renovation sites change. Recheck critical dimensions after demolition or cabinet installation if the first survey happened early. The final production release should cite the latest drawing and survey date.
A short second visit costs less than discovering that a finished basin follows an obsolete opening. Treat the survey as a controlled project document, not a casual note.
Planning a replacement basin? Send QINGDA the marked site drawing, photos, plumbing positions, required quantity, and target installation date for review.