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PGT Home Additions & ADU: The Redwood City Owner’s Guide
PGT-compatible window and door systems for home additions and ADUs in Redwood City typically run $45,000-$130,000 installed, depending on whether you’re extending an existing footprint or building a detached unit. We stock PGT WinGuard and EnergyVue series hardware, tracks, and sash components for same-day replacement on most service calls. Most Redwood City owners first notice a problem when a PGT window in their new addition won’t stay open, seals fog between panes, or the locking mechanism grinds after a season of Peninsula temperature swings.
Which PGT Models This Applies To
We service and stock parts for PGT’s three residential lines found in Redwood City additions and ADUs: WinGuard (impact-rated vinyl and aluminum), EnergyVue (vinyl non-impact), and the older PGT 5400/5500 aluminum series still common in pre-2015 builds near Mount Carmel and Farm Hills. The critical compatibility point is the sash width and track profile, not just the rough opening. WinGuard and EnergyVue use different roller assemblies, and swapping them causes binding within weeks. Check the etched mark in the glass corner or the sticker on the frame header for the series code. OEM PGT parts ship from Florida in 5-10 business days; we stock quality aftermarket rollers, balances, and weatherstripping that match PGT tolerances and carry the same 365-Day Done Right Promise. For impact-rated units, we source PGT-certified laminated glass through our Bay Area distributor to maintain the HVHZ rating, which matters for permit sign-off in San Mateo County.
Signs Your PGT Home Additions & ADU Is Failing

- Window drops or won’t stay open. The coil balance system has lost tension, usually from corrosion in the metal housing. Redwood City’s marine air accelerates this; we see it most in south-facing additions where condensation collects in the jamb.
- Fog between double-pane glass. The insulated glass unit (IGU) seal has failed, releasing the argon fill. Once moisture enters, the Low-E coating degrades and the thermal performance drops measurably.
- Locking mechanism sticks or grinds. The multipoint lock hardware has worn or the keeper has shifted with seasonal framing movement. In older Redwood City homes with raised foundations, this shows up after the first winter.
- Air leaks around the frame. Compression weatherstripping has flattened or the sill track gasket has pulled free. You’ll feel it as a temperature drop near the window on windy days along the 101 corridor.
- Impact glass shows spider cracks but hasn’t shattered. The interlayer (PVB or SentryGlas) has delaminated from UV exposure. The window still blocks windborne debris structurally, but the optical clarity is gone and the rating is compromised.
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AfterReplacement Cost & What’s Included
For a full PGT window replacement in a Redwood City home addition or ADU, expect $800-$2,400 per opening depending on size, series, and whether the frame needs re-flashing. IGU-only replacement (glass swap, keep the frame) runs $350-$850 per sash. Hardware-only repairs, balance or lock replacement, typically fall between $180-$450. Every quote is a flat written price with line-item parts and labor, delivered before work starts, under Clause 1 of the Haven Standard. We pull permits when required by San Mateo County and include a documented photo record of the opening condition, the install, and the final weather-sealing test. Our 365-Day Done Right Promise covers the installation and the part.
DIY or Call Us?

An owner can safely check the series code, measure the visible glass dimensions, and confirm whether the issue is the lock, balance, or seal, but we don’t recommend removing a PGT sash or IGU yourself. Impact-rated units weigh 40-60 pounds and the frame clips require a specific release sequence; forcing them cracks the vinyl jamb or shatters the laminated glass. For non-impact vinyl windows, a determined homeowner can swap a balance or weatherstrip, but misaligned hardware voids the warranty and creates an egress failure. We’re not affiliated with PGT, but we install enough of their product in Redwood City that our trucks carry the common rollers, balances, and lock sets. Call (650) 560-7228 and we’ll confirm what you need before dispatching.
FAQs
Vinyl and aluminum PGT frames last 20-30 years with basic maintenance, but the IGU seals typically fail in 12-18 years here because of the thermal cycling between cool marine mornings and direct afternoon sun. The coastal salt air also corrodes balance hardware faster than inland Bay Area locations. Call (650) 560-7228 for an exact quote - estimates are free.
IGU fogging requires glass replacement, not repair; the seal cannot be re-established in the field. If the frame is square and the hardware functions, we replace just the IGU, which cuts the cost by roughly half versus full unit replacement. Call (650) 560-7228 for an exact quote - estimates are free.
A single IGU swap takes 90 minutes; a full unit replacement with exterior trim and flashing repair runs 3-5 hours per opening. Full ADU or addition window sets are scheduled as multi-day projects with sequencing to maintain weather protection. Call (650) 560-7228 for an exact quote - estimates are free.
We stock aftermarket rollers, balances, locks, and weatherstripping that match PGT specifications. OEM impact glass and specialized frame components are next-day or 5-10 day from our distributor, depending on the series. We verify fit before ordering so you’re not waiting for the wrong part. Call (650) 560-7228 for an exact quote - estimates are free.
We also stock and install parts for KraftMaid, Cambria, and Silestone products.
Measure twice, document once, build it so it doesn’t come back. That’s how Grant Rowan has run every crew since 2007.
Ready to get your PGT addition or ADU back to spec? Call (650) 560-7228 to schedule your free estimate. We’ll review the issue, confirm the series and part, and deliver a written flat price before any work starts.
Written by Grant Rowan, Owner, Rowan Construction Group Redwood City at Rowan Construction Group Redwood City, serving Redwood City and nearby areas.







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