Window wall is the dominant glazing system for Florida's multifamily residential market. If you're building towers, you're dealing with window wall — and the coordination challenges it creates are substantial. Here's what GCs need to know.
What Is Window Wall?
Window wall is a slab-edge-bearing glazing system — it spans from slab to slab on each floor but bears its load on the concrete slab rather than transferring loads back to the building structure through anchors the way curtainwall does.
This distinction matters for coordination: window wall installation requires the slab edges to be properly formed and dimensionally accurate before the system can be installed. If your slab pours have significant dimensional variation, the window wall system needs to accommodate it — which typically means adjustable anchoring systems with built-in tolerance.
System Selection
Window wall systems come in two primary configurations:
Slab-Edge Systems
The most common configuration for Florida concrete-frame multifamily. The system bears on the slab edge at each floor, with the unit spanning the full floor-to-floor height. Installation is floor-by-floor, sequencing with the structural frame.
Infill Systems
Some projects specify window wall that spans between structural spandrel beams or intermediate structural members. These systems have different bearing conditions and require specific coordination with the structural engineer.
For most Florida multifamily projects, slab-edge systems are the appropriate choice. ACG can evaluate the structural conditions on your specific project and recommend the right system configuration.
Coordination Requirements
Window wall creates more coordination requirements than any other glazing system type. The major interfaces:
Structural Frame
Slab edge dimensions and locations must be consistent across all floors. Significant variation — more than 3/4" in most window wall systems — requires shimming or remediation. ACG reviews structural drawings during design and flags tolerance issues before they become field problems.
Waterproofing
The interface between the window wall system and the building's air/water barrier is critical. ACG coordinates with your waterproofing contractor to establish the sequence and interface detail before installation begins. This detail determines whether the building envelope is watertight — and discovering it wrong at closeout is expensive.
Framing and Drywall
Interior framing and drywall must accommodate the window wall system's interior perimeter condition. ACG provides the finished interior dimension requirements to your framing contractor during the coordination phase.
MEP
Mechanical equipment, electrical conduit, and plumbing that runs at the perimeter must be coordinated with window wall anchor locations. ACG flags conflicts during shop drawing preparation.
HVHZ Requirements for Multifamily
South Florida multifamily towers are in the HVHZ. Every window, balcony door, and glazed panel in the system must be impact-rated with a valid Miami-Dade NOA or Florida Product Approval.
The practical implications:
- All glazing must be laminated (or impact-resistant) with tested configurations
- Framing systems must have specific anchor spacing and installation methods per the NOA
- Hardware — including balcony door hardware — must be hurricane-rated
- Shop drawings must reference the applicable NOA for each component
ACG uses ESWindows and Slimpact systems for HVHZ multifamily projects. Both product lines have current Miami-Dade NOA listings for their window wall configurations.
Installation Sequence
Typical window wall installation sequence on a multifamily tower:
- Structural frame complete to the floor being glazed (typically 2-3 floors below the leading edge of construction)
- Slab edge survey to document actual dimensions vs. design
- Track and anchor installation at slab edges
- Window wall unit installation and temporary bracing
- Perimeter sealant application after all units in a bay are installed
- Interior perimeter trim and finish installation
ACG sequences our window wall installation to stay appropriately behind the structural frame and ahead of the interior finishing trades. We don't create the schedule conflicts that result from poor coordination.
Common Problems — and How ACG Avoids Them
Out-of-tolerance slab edges: ACG surveys slab edges before ordering materials and flags conditions that exceed system tolerances. We address these before units arrive on site, not after.
Sealant failures: Perimeter sealant failures are the most common cause of water infiltration in window wall systems. ACG uses the sealants specified in the NOA, applied by trained installers following the manufacturer's application requirements.
Hardware alignment: Balcony doors with misaligned hardware are a persistent punchlist issue on multifamily projects. ACG installs door hardware using alignment jigs and performs operational testing before turning over each floor.
If you're building multifamily in Florida, send us your plans. We'll give you a clear scope of the window wall work, system recommendations for your specific conditions, and a schedule that integrates with your project's construction sequence.