Window sills and thresholds are small details that leak, blacken or trip you when done wrong. Hong Kong owners most often slip up on bathroom thresholds without damming and sills without drip edges. This guide covers choice, measuring and fixes.
Threshold Damming
Bathroom thresholds (door stones) separate wet and dry and dam water. The threshold should sit about 10–15mm above the bathroom floor to hold water in. Vital in small Hong Kong bathrooms. See the threshold & sill guide.
Window Sill Drip Edge
External window boards need a drip edge (groove or slope) so rain does not run back into the wall. Without it, rainy days blacken and mould the wall below.
Stone Choice
Use marble or granite. Interior thresholds and sills: marble is pretty and hard enough; wet or outdoor thresholds: granite for wear and damp resistance. Dark marble (Black Marquina) hides stains on thresholds.
Correct Measuring Steps
- Measure clear opening width and depth, allow for wall embedment;
- Threshold: include damming height and end joints;
- Sill: include outward overhang and drip-edge position;
- Confirm thickness (18–20mm) and laminated edge.
Common Leak Causes
Thresholds not embedded, hollow bedding, missing drip edge, aged caulk — all leak. Bed fully, embed ends, then water-test. Book a free measurement to plan it.