Installing an Impact Window Yourself: From Permit to Inspection
Updated · See the full hurricane impact windows cost comparison
Installing 10 impact windows yourself: $7,830–$8,330 in units, bucks, sealant and permit, 40–60 hours — and a voided warranty.
- This is a guide to one window, for someone who has set windows before and can pull an owner-builder permit. For a whole house, the cost page says hire it — the saving isn't worth the warranty, the credit and the leak risk.
- The product approval is the instruction sheet. Anchor type, spacing, embedment, sealant and buck details come from the approval and the manufacturer's installation document, not from a video.
- Measure the opening in three places each way and order to the manufacturer's sizing rule. A unit 1/2 in wrong is a 12-week reorder.
- Water is the failure: bucks sealed, flashing lapped like shingles, backer rod under the sealant, and a hose test before the stucco goes back.
Before you start
Read the cost comparison first. It says hire a licensed installer, and the reasons don’t change here: the warranty, the insurance credit and the permit history all favor a documented professional install, and a single window costs about the same either way once the permit and tools are counted. This guide is for the narrow case where a homeowner who has set windows before is replacing one unit in an accessible opening under an owner-builder permit — and for understanding what the installer is doing on the day the crew shows up.
Two conditions before you commit: the building department will issue the permit to you, and you can buy an approved unit with its approval document and installation instructions.
What you need
An impact window with its product approval for the required design pressure and the manufacturer’s installation instructions; pressure-treated buck lumber where the approval calls for it; the concrete anchors specified, with the bit size they need; shims; polyurethane sealant and backer rod; flashing tape if specified; low-expansion foam; stucco patch and paint. Tools: a hammer drill, a reciprocating saw rental, glass suction cups, a 4 ft level, a square, a caulk gun, a pry bar, and safety glasses and gloves. The priced list is on the cost page.
The two things that decide how it turns out
The approval document. Every anchor’s location, size and depth, every sealant joint and every buck detail is in it, and the inspector reads from it. There is no other correct way to install the window.
Water management. Wind is what the glass is for; water is what the install is for. Sealed bucks, a bedded frame, backer rod and tooled sealant, flashing lapped the right way, and a hose test before anything is covered. A leak behind stucco is found years later, by which time it’s a wall.
Step by step
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Check the rules and pull the permit
Call the building department: is an owner-builder permit available for this scope, what's the required design pressure for your opening (they'll tell you or refer you to the wind map), and what inspections are required. Apply with the product approval number and the manufacturer's installation instructions for the exact unit. Confirm your HOA allows it.
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Measure and order
Pull the interior trim, measure the opening in three places each way, check square and plumb, and order the unit to the manufacturer's sizing rule with the design pressure your opening needs. Get the approval document and installation instructions in writing with the order. Then wait 8–16 weeks.
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Remove the old window
Cut the old sealant, back out or cut the fasteners with a reciprocating saw, and pull the frame. Remove the old bucks if they're rotten or not to the approval; keep them if they're sound pressure-treated wood anchored to the block. Clean the opening to bare block or framing and check for water damage.
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Set the bucks
Where the approval calls for bucks, cut pressure-treated lumber to the opening, seal the back face to the block with polyurethane sealant, and anchor it to the block with concrete screws at the approval's spacing and embedment. Check the finished buck opening for square and size against the window.
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Dry-fit, then set the window
With a helper and suction cups, set the unit into the opening on shims at the sill, check it's centered, plumb and square (diagonals), and mark the anchor holes. Remove it, run the continuous sealant bead the instructions specify at the sill and jambs, and set it again. Shim at each anchor location so the frame can't bow when the screw draws it in.
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Anchor per the approval
Drill and drive the anchors at exactly the spacing, edge distance and embedment in the approval — every hole, including the ones that seem excessive. Check the sash operates smoothly after each side is fastened; binding means the frame is racked. Cap the screw heads per the instructions.
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Seal, flash and test
Backer rod in the exterior gap, a tooled polyurethane bead over it, flashing tape where specified lapped bottom to top, low-expansion foam or sealant at the interior gap. Run a hose over the exterior for ten minutes and check inside for any water. Fix it now.
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Finish and get inspected
Patch the stucco with a matching mix, replace the interior trim and paint. Call for the final inspection with the approval and instructions on hand; the inspector will check the anchors and the product label. Keep the permit, the approval and the inspection in the house file — the wind-mitigation inspector and the next buyer will want them.
What would this cost you? The hurricane impact windows calculator prices the DIY version with the tools you already own and a value on your time, next to a pro quote.
Frequently asked questions
Can a homeowner pull a permit for impact windows?
In Florida, yes — an owner-builder permit for an owner-occupied home you won't sell within a year, with an affidavit accepting the contractor's responsibilities. Several other states have similar exemptions; some coastal jurisdictions don't allow it for structural openings. The building department will want the product approval number for the exact unit, and the final inspection checks the anchors against it. Ask before ordering anything.
Where can I buy impact windows as a homeowner?
It's the hard part. The major impact brands sell through certified dealers and installers, and many dealers won't sell units without installation because the warranty and the liability travel with the install. Some regional manufacturers, building-supply houses and the big-box stores' special-order desks will sell approved units to a homeowner; expect a 8–16 week lead and no returns. Get the product approval number for the unit before you pay.
How do I measure for a replacement impact window?
Remove the interior trim to see the rough or buck opening. Measure width at top, middle and bottom and height at left, center and right; use the smallest of each. Then apply the manufacturer's sizing rule for that frame type — typically the window is ordered 1/4 to 1/2 in smaller than the opening in each direction for shims and sealant. Check the opening for square (diagonals within 1/4 in) and plumb; an out-of-square block opening is shimmed, not forced.
What anchors do impact windows need in concrete block?
Whatever the product approval says — and only that. Typical is 1/4 in concrete screws (Tapcons or equivalent) through the frame or the buck into the block, at a spacing of 6–12 in with a set distance from each corner and a minimum embedment of 1 1/4 to 1 3/4 in, with the anchor schedule changing by design pressure and window size. Through wood bucks, the buck itself is anchored to the block first. The inspector counts them.
How do you flash and seal an impact window in a stucco wall?
Per the manufacturer's instructions, which the approval references. Generally: the buck is sealed to the block with polyurethane sealant; the frame is bedded in a continuous bead at the buck; the frame flange or the joint between frame and buck is sealed; and the exterior gap between the frame and the stucco return gets backer rod and a tooled polyurethane bead, not a caulk gun smear. Where flashing tape is specified, it laps like shingles — bottom, sides, then top. A garden hose on the finished install before patching finds the leak now instead of in two years.
How heavy is an impact window?
A 36×48 aluminum single-hung with laminated glass is 80–120 lb; larger units 150 lb; a sliding glass door panel 150 lb and its frame 300. Two people, glass suction cups, and a plan for how it goes into the opening before you lift it. Laminated glass cracks if the frame is twisted while it's being set — keep it square and supported on shims, never on a corner.
Will a DIY impact window count for my insurance discount?
Only with the permit, the final inspection and the product approval on file. The wind-mitigation inspector who fills out the discount form needs to see that every opening is protected by an approved product and, for the credit, documentation of it — a permit record is what they look for. An unpermitted install gets no credit, and a house with one unprotected opening drops to the lower credit tier regardless.
Sources
- Glaziers (SOC 47-2121), Occupational Employment and Wage Statistics , U.S. Bureau of Labor Statistics, 2026-04
- How Much Do Hurricane Windows Cost? , HomeGuide, 2026-09
- How Much Do Impact Windows Cost? , Angi, 2026-09
- How Much Do Hurricane Windows Cost? , Forbes Home, 2026-09
- Florida Product Approval System , Florida Department of Business and Professional Regulation, 2026-09
- Product Control: Notices of Acceptance , Miami-Dade County, 2026-09
- Uniform Mitigation Verification Inspection Form (OIR-B1-1802) , Florida Office of Insurance Regulation, 2026-09
- Protect Your Windows and Doors , Federal Alliance for Safe Homes, 2026-09
Figures last reviewed . See how we estimate.