Most commercial storefront installation problems are preventable. After 350+ Florida commercial projects and 1M+ SF installed, the same failure modes recur: misread NOA frame size envelopes, anchors into the wrong substrate, glass make-up substitutions, sealant compatibility oversights, blocked weeps, missing expansion joints, and failed field coats. This page documents the top seven errors — what they are, why they matter, and how qualified glazing contractors prevent them. It is written for general contractors and architects evaluating subcontractor practices.
Every Florida NOA certifies a storefront system up to a specific maximum frame width and height. These dimensions represent the largest opening size tested at the certified design pressure. A frame installed in an opening that exceeds the NOA's tested size — even marginally — is not covered by the NOA. On HVHZ projects, this is a code compliance failure that can result in the permit inspector requiring the non-compliant frame to be removed and replaced. The fix requires confirming every opening dimension against the NOA table during the shop drawing and material ordering phase, not at field installation. ACG verifies opening dimensions against the NOA table on every project as part of shop drawing preparation.
NOAs specify not just fastener type and spacing but the substrate the fastener must engage. An anchor specified for solid grouted CMU installed instead into a hollow ungrouted cell fails at a fraction of the required pull-out capacity. Anchors specified for 3,000 psi concrete installed into 2,000 psi block fill perform similarly. On light-gauge steel stud openings, anchors set through sheathing without engaging the framing member have negligible structural value. Substrate verification before anchor installation is a required step — not optional. On HVHZ projects, the anchorage configuration must match the NOA detail exactly; field substitutions are not acceptable without engineering review.
The glass make-up listed in a Florida NOA — thickness, heat treatment, interlayer type and thickness, coating, and any laminate configuration — is the make-up that was tested and certified. Substituting a different glass make-up, even if it appears equivalent, produces a different structural and thermal performance profile that was not part of the testing protocol. Common substitution errors include using annealed glass where heat-strengthened or tempered is required, changing interlayer thickness in laminated units, and substituting a different coating type. Any glass make-up change from the NOA-specified configuration requires engineering review and, in some cases, a new NOA.
Commercial storefront uses multiple sealant products that must be chemically compatible with each other and with every substrate they contact: the aluminum frame finish, the glass surface or coating, the concrete or CMU substrate, foam backer rod, and any tape sealants at frame joints. A common failure scenario is applying a perimeter weather sealant to a surface that already has residue of an incompatible primer or a different sealant chemistry — resulting in immediate adhesion failure of the new sealant. Always confirm compatibility through the sealant manufacturer's published compatibility data for every material contact in the system before ordering materials.
Weep slots are designed openings in the sill extrusion that drain water from the frame cavity to the exterior. They are frequently blocked during construction by caulk over-application, debris accumulation during rough opening work, or paint overspray. Some installers — incorrectly — intentionally seal weep slots to prevent bug or air infiltration, not understanding that the system depends on drainage as part of its water management design. Blocking weeps forces any water that enters the glazing pocket or frame cavity to accumulate until it overflows to the interior. Weep slots must be open and clear at installation closeout and verified at every annual inspection.
Aluminum has a coefficient of thermal expansion of approximately 0.0000128 in/in/°F. A 50-foot run of aluminum storefront framing will move approximately 3/8" across Florida's seasonal temperature range. Without expansion joints at intervals specified in the shop drawings — typically every 20–25 feet for stick-built storefront — this movement is transferred to glass lites (causing stress fractures), perimeter sealant (causing tearing), or frame-to-frame joints (causing buckling or separation). Expansion joint omissions are frequently driven by field crew decisions made without reference to the shop drawings. The glazing foreman must review expansion joint locations before installation begins.
When storefront frames require field-applied coatings — touch-up paint, anodize repair, or color-match coatings — improper application produces visible color variation, poor adhesion, and premature coating failure. Aluminum finish systems (anodize, PVDF, FEVE, acrylic) each require specific surface preparation, compatible primers, and application parameters. Applying a touch-up paint designed for interior use to an exterior aluminum frame finish causes rapid UV degradation and visible chalking. Field coating must match the original factory coating chemistry and must be applied to properly prepared surfaces per the coating manufacturer's data sheet.
The seven mistakes above share a common thread: each results from a disconnect between the information in the project documents — the shop drawings, the NOA, the sealant manufacturer's data sheet, the specification — and the decisions made by field crews during installation. This disconnect is organizational, not technical. It occurs when:
On ACG projects, the pre-installation package given to field crews includes the approved shop drawings, the NOA page with the frame size table and anchorage detail highlighted, the glass make-up schedule, the sealant schedule with compatibility confirmations, and the expansion joint location diagram. Pre-installation verification is a documented step, not an assumed one.
Preventing these errors requires specific process controls at each phase of the project:
| Phase | Control | Prevents |
|---|---|---|
| Shop drawing preparation | Verify every opening against NOA frame size table; flag any opening at or near NOA limit | Mistake #1 (NOA envelope) |
| Material ordering | Glass make-up schedule signed off against approved NOA; no field substitutions without written approval | Mistake #3 (glass substitution) |
| Material receiving | Verify sealant product matches specification; confirm manufacturer compatibility data for all substrate contacts | Mistake #4 (sealant compatibility) |
| Pre-installation | Substrate inspection confirms substrate type, strength, grout, and anchor zone adequacy before any work begins | Mistake #2 (wrong substrate) |
| Installation | Expansion joint locations verified against shop drawings before any extrusion is cut; foreman sign-off before sill is set | Mistake #6 (expansion joint omission) |
| Glazing / closeout | Weep slot inspection and clearance documented; water test performed and documented | Mistake #5 (weep blockage) |
| Touch-up / closeout | Field coating product confirmed against factory finish type; surface prep documented | Mistake #7 (field coat failure) |
Misreading the NOA frame size envelope is the most consequential on Florida projects. An NOA certifies a system only up to the maximum tested frame dimensions. Frames installed larger than the tested envelope fall outside NOA coverage and may require removal on HVHZ or WBDR projects.
Multiple sealant types are used at different locations in a storefront system. Incompatible products can cause adhesion failure, staining, or chemical degradation of adjacent materials. Compatibility must be confirmed through manufacturer data for every material contact in the system before any sealant is ordered or applied.
Blocked weep slots prevent sill cavity drainage. Water accumulates until it overflows to the interior, producing leaks that mimic perimeter sealant failure. In severe cases, aluminum corrosion and steel framing rust can result from prolonged standing water in a blocked sill extrusion.
A substitution occurs when installed glass differs from the NOA-specified make-up — different thickness, heat treatment, interlayer, or coating. The NOA only covers the tested configuration. A different make-up has different structural performance and may not meet the required DP rating, creating a code compliance issue.
Aluminum expands and contracts significantly with temperature change. A 50-foot run moves approximately 3/8" across Florida's seasonal range. Omitting expansion joints transfers this movement to glass, sealant, or anchors — causing stress fractures, sealant tearing, or frame distress.