Module 3: Installation Techniques & Best Practices
3.1 Pre-Installation Checks
A successful curtain wall installation begins with thorough preparation to avoid costly rework.
Surveying & Setting Out
Laser Scanning & As-Built Verification: Ensures the building structure matches design dimensions.
Control Lines & Benchmarks: Establishes reference points for mullion alignment.
Tolerance Checks: Confirms floor flatness (±3mm) and slab edge straightness.
Anchor Placement Verification
Anchor Bolt Survey: Checks position, embedment depth, and thread condition.
Load Testing: Proof-testing anchors (e.g., Hilti HY 200) to verify pull-out strength.
Shimming Requirements: Identifies areas needing leveling adjustments before mullion installation.
3.2 Structural Frame Installation (Mullions & Transoms)
The frame provides the backbone for the curtain wall system.
Key Steps
Mullion Erection:
Sequencing: Typically installed top-down or bottom-up, depending on access.
Plumb & Alignment: Laser levels ensure ±1.5mm/m tolerance.
Interstory Joints: Slip connections accommodate building movement.
Transom Installation:
Thermal Breaks: Insulated shear blocks prevent thermal bridging.
Splice Connections: Bolted or welded per engineering specs.
Common Pitfalls
Over-Torquing Bolts: Can distort aluminum extrusions.
Improper Shim Usage: Must be stainless steel to prevent corrosion.
3.3 Glazing Methods
Wet Glazing vs. Dry Glazing
Pressure Plate Systems
Mechanical Retention: Aluminum or stainless steel plates clamp glass to the frame.
Cap Bead Sealant: Secondary weather seal applied after plate installation.
Tolerance Management: Shim adjustments ensure even pressure distribution.
3.4 Unitized Panel Installation
Pre-fabricated panels demand precision handling to maintain efficiency.
Critical Phases
Lifting & Handling:
Vacuum lifters or spreader beams prevent glass stress.
Temporary bracing until full stabilization.
Installation Sequencing:
Typically follows a "checkerboard" pattern to balance loads.
Firestop integration at floor divisions.
Tolerances:
Panel-to-panel joint width (±2mm).
Cumulative vertical tolerance ≤10mm over 10 stories.
Common Errors
Forced Fit: Never mechanically force misaligned panels.
Missing Isolation Pads: Causes galvanic corrosion (steel vs. aluminum).
3.5 Sealant Application & Weatherproofing
The final defense against water and air infiltration.
Best Practices
Joint Preparation:
Backer Rod Selection: Closed-cell foam rods (1.5x joint width).
Surface Cleaning: Solvent wiping (e.g., isopropyl alcohol) for adhesion.
Sealant Application:
Tooling: Concave profile (depth = 1/2 width) for optimal performance.
Curing Conditions: 4°C–40°C, RH <85% for silicones.
Weatherproofing Tests:
Field Water Testing: AAMA 501.2 spray rack evaluation.
Dye Testing: Detects hidden leaks in sealant joints.
Materials Comparison
Key Takeaways
Pre-Installation Checks prevent alignment and anchor failures.
Frame Accuracy is critical for subsequent glazing/panel fit.
Glazing Method Choice depends on project speed vs. complexity.
Unitized Panels require meticulous sequencing to avoid cumulative errors.
Sealant Workmanship directly impacts long-term weather resistance.
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