Residential Specialty Glass
This domain tests decorative and specialty glass: leaded and copper-foil panels, bevelled glass, etched and sandblasted finishes, textured glass, glass block and residential glass features such as railings and partitions. The exam focuses on structural support, reinforcement and knowing when a decorative product is not safety glazing.
Decorative and leaded glass
- Leaded glass uses lead came, solder and cement. Lead came is not structural; panels need steel reinforcement bars or rebar at intervals of about 300–450 mm, anchored to the frame with copper ties.
- Copper foil is used for small, lighter panels and is less structural than lead came.
- Bevelled glass is heavy. Use zinc or lead came and provide adequate framing and support; do not rely on the came alone to carry the panel weight.
- Etched, sandblasted, frosted and textured glass provide privacy, not impact safety. In doors, sidelights or other safety-glazing locations, specify tempered or laminated glass.
Glass block and specialty applications
- Glass block is assembled with mortar or silicone, needs expansion joints and reinforcement, is not loadbearing and requires weep paths.
- Glass railings use laminated or tempered-laminated glass with an engineered base shoe; ordinary annealed glass is unacceptable.
- Partitions and backsplashes often use tempered glass with clamps; avoid point loads and allow movement.
Worked example
A leaded panel 900 mm × 1200 mm is to be installed in a fixed interior frame. Because lead came is not structural, provide vertical reinforcement at approximately 300–450 mm centres-at 400 mm and 800 mm-plus a horizontal bar at mid-height, and anchor the panel to the frame with copper ties. If the same panel were proposed for a door or sidelight, it would need to be safety glazing; decorative leaded glass alone does not comply.
Traps that cost marks
- Assuming textured or patterned glass is safety glazing.
- Treating lead came as a structural member.
- Overheating glass during soldering and causing thermal cracks.
- Installing a heavy bevelled panel without adequate support.
- Using annealed glass in a railing or guard.
Mirrors and Shower Doors
This domain tests mirror layout, substrate preparation, adhesive selection and edge sealing, plus shower door measurement, tempered-glass requirements, hinge anchorage and water management. Exam questions often describe a failing mirror or a leaking frameless shower door and ask for the cause and correction.
Mirror installation
- The substrate must be flat, dry and clean. Avoid direct contact with concrete or masonry, which can attack the mirror backing.
- Use neutral-cure mirror mastic in dabs with air gaps, plus wall clips at the bottom. Raise the mirror off the counter and seal the edges to keep moisture out.
- Safety backing or laminated mirror is required in gyms and dance studios where impact is possible.
- Cut mirror by scoring and snapping; grind edges and drill with a diamond bit from both sides to reduce chipping.
Shower doors
- Shower doors require tempered safety glass. Framed units commonly use 6 mm glass; frameless units commonly use 8–10 mm glass.
- Measure the opening at the top, middle and bottom, and check plumb and square. Use the smallest width and verify diagonals before ordering.
- Hinges must anchor into studs or added blocking, not drywall anchors. Provide seals, a bottom sweep and weep holes so water drains.
Worked example
A frameless shower opening measures 900 mm at the top, 896 mm at the bottom and 894 mm at mid-height. Use 894 mm as the controlling width. Check the diagonals; if they differ by more than about 3 mm, correct the wall or use adjustable hardware. For a frameless door with 6 mm clearance at each hinge side, the panel width is approximately 894 − 12 = 882 mm. Confirm hinge blocking is present before drilling.
Traps that cost marks
- Measuring only at the bottom of a shower opening.
- Using annealed glass in a shower door.
- Sealing weep holes in the bottom rail and causing water to stand.
- Applying mirror mastic directly to fresh concrete or masonry.
- Omitting edge sealant on a mirror installed in a humid bathroom.