Installing Impact Windows: Measure to Final Inspection

Installing impact windows begins with two distinct measurements: daylight opening (DLO) and tip-to-tip. Per PGT's measuring guide, WinGuard Vinyl windows are ordered by DLO with a 5/8-inch flange, while aluminum products are ordered tip-to-tip with a 1/2-inch flange. Both methods calculate opening size using 1/8-inch shim space, with a hard maximum of 1/4 inch. Getting this wrong means a unit that either won't fit the rough opening or creates a shim gap that violates the approval drawing, both outcomes require a costly re-order. Beyond dimensions, the measuring visit confirms wall thickness, substrate type (concrete/CMU, wood framing, or metal stud), and whether a buck strip is needed. Florida law under Fla. Stat. 489.126 requires a contractor who collects more than 10 percent of the contract price upfront to apply for permits within 30 days and start work within 90 days of permit issuance. That clock starts at deposit, so measuring and ordering must happen quickly. A notice of commencement (NOC) must be filed before the first inspection on any contract exceeding $5,000 under Fla. Stat. 713.135.

Delivery day is the first quality gate. PGT's Product Handling and Storage Recommendations require crews to inspect each unit at delivery for size, type, operation, impact rating, and visible damage. Critically, you must confirm the unit fits the prepared opening before removing the existing window, once the old window is out, the opening is exposed to weather. On a typical South Florida project, units should be stored upright, out of direct sunlight, leaning no more than 10 degrees from vertical. Protective film on laminated glass must be removed immediately after installation, per PGT's handling guidance. Crews staging units inside the home should keep them away from high-traffic paths to avoid edge chips. For a broader look at what our impact windows installation service covers, from product selection through permit closeout, that page details SafeGuard's full scope. Checking the job-site NOA packet at delivery is equally important: Miami-Dade NOA 25-0520.01 requires a copy of the entire NOA to be available on site at the Building Official's request.

Florida Building Code Section 1626.2 (HVHZ large missile test) requires that fasteners used in field installations be identical in size and spacing to those used in the tested specimens. The test involves a 9-pound 2x4 timber striking at 50 feet per second. That standard makes fastener substitution illegal, not just inadvisable. Miami-Dade NOA 25-0520.01 for PGT's SH-5500 shows 4 anchor configurations. These are: through the frame into concrete/CMU, through a 1x buck strip, into 2x wood framing, or into metal framing. Each configuration specifies embedment depth, anchor diameter, and spacing. The crew determines the site-specific design pressure from ASCE 7 tables. They then select the anchor group from the NOA that meets or exceeds that pressure. The 1/4-inch maximum shim applies to every anchor group. Understanding how Florida Product Approvals and Miami-Dade NOAs differ is covered on our Florida Product Approval vs Miami-Dade NOA explainer. Each document governs different things. Fla. Stat. 553.842(4) confirms that a statewide product approval bars local jurisdictions from requiring additional testing. This applies as long as the product is used within its approval conditions.

Miami-Dade's Fast Track window/door permit process requires a single '102-Buck and Fastener' inspection. It is requested only after all windows are installed. It must be requested before the interior frame perimeter is caulked, sealed, or finished. Inspectors must be able to see the shim space clearly. Fastener cover plates cannot be installed yet. This inspection is both structural and final: it closes the permit. It can be conducted virtually or on site. Our Miami-Dade impact window permit guide details the full Fast Track submission checklist. In Broward County, Pembroke Pines requires 2 separate inspections. These are a structural attachment inspection and a standalone final. At the attachment inspection, all openings must be installed with no trim, casings, or interior caulk. Exterior caulk is allowed to keep the opening watertight. The permit card, construction drawings, and product approvals must be physically present. Our Broward County impact window permit guide covers additional municipalities. It includes their specific portal requirements and typical review sequences.

Once the inspector approves the anchoring, interior trim and caulk can go on. Protective film must be peeled from laminated glass immediately after installation. Exterior caulk between the frame and the wall cladding is applied last, after structural sign-off. PGT's replacement product warranty is explicit: caulking or sealant between the product and exterior cladding is not part of the product, is not warranted, and is the homeowner's maintenance responsibility. Failure to re-caulk when the exterior sealant cracks or separates is treated as failure to properly incorporate the product into the building envelope, a warranty exclusion. Plan to inspect exterior sealant annually, especially after a severe storm season. Two code items apply to replacement windows specifically. First, a replacement window serving as a required emergency egress (escape) opening is exempt from R310.2 minimum-size rules under Florida Existing Building Code Section 702.5, provided it is the manufacturer's largest standard size that fits the existing frame and matches the original operating style or one with equal or greater opening area. Second, window sill heights over 72 inches above grade may require fall-protection glazing, confirm with your permit drawings.

Miami-Dade County has confirmed that the Florida Building Code Ninth (2026) Edition takes effect December 31, 2026. Permit applications submitted through the online portal after 4 PM on December 30, 2026 must comply with the 2026 edition. The current Eighth Edition will no longer apply after that cutoff. Products tested under the current code cycle may need updated approval documents under the new edition. The Florida Building Code publishes edition transition guidance as code cycles advance. Pulling your permit before that cutoff locks your project into the current approval cycle. It also avoids re-submittal delays caused by the edition transition. SafeGuard closes more than 1,200 impact-window, impact-door, and roofing projects per year. All work is executed by in-house crews with no subcontracted field work. That means permit tracking and inspection scheduling stay inside a single accountable team. All 20 crews operate across South Florida under that same structure. If you're weighing whether to tackle installing impact windows yourself, our DIY vs professional impact window installation guide explains why. Approval drawings and permit inspections make self-installation extremely difficult to do legally.