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Red Stag Windows & Doors logoRed StagWindows · Doors · LA
Retrofit Window Installation

Retrofit Window Installation Los Angeles

Block-frame swap with no stucco cut. The fast, clean option for LA stucco homes when the existing frame is sound. Milgard, Anlin, Marvin, Andersen. Lifetime install warranty. Quote in 48 hours.

$3,000+
Project range starts
1 day
Typical install
Lifetime
Install warranty
LA homes
Post-1985 stucco specialty
Retrofit reality check

When retrofit is right (and when it isn't).

Block-frame retrofit is the most common window install in Los Angeles — and the most often misapplied.

The reason retrofit dominates SoCal is structural: most LA tract homes built between 1985 and 2005 are stucco over wood frame with aluminum window fins set behind the lath. Cutting stucco to do a full-frame replacement means demolishing two to three inches of finish around every opening, then patching, color-matching, and waiting two weeks for the new stucco to cure before paint. On a 12-window Granada Hills ranch, that adds $6,000–$9,000 and three weeks to the job. Block-frame retrofit skips all of that — we leave the existing aluminum or vinyl frame in place and set the new window inside it, sealing to the original fin from the outside. One day on site for most homes, no stucco patch, no paint touch-up.

The trade-off is glass area. A retrofit window sits inside the old frame, so you lose roughly 1" of visible glass on each side — about 8% of the daylight opening on a typical 36×48 window. We show you a tape-measure mockup at the consult so it's not a surprise on install day. The other trade-off is what we can't see: with the old frame staying in place, we can't inspect the rough opening for hidden water damage, dry rot, or termite work. On a 1995 Porter Ranch home that's usually fine. On a 1962 Burbank home that had a roof leak in 2008, it's a problem we'll never find until the wall comes apart.

The cutoff we use is roughly 25 years and visible condition. Anything post-1985 with intact stucco, no interior staining, and a sound frame is a retrofit candidate. Anything older, anything with paint bubbling near the sill, or anything where the existing frame is bent, corroded, or out of square is a full-frame job. We tell you which bucket you're in at the measure — and we walk away from retrofits that should be full-frame, even if you push us.

Pricing breakdown

Three retrofit tiers, real numbers.

All-in per-window pricing for block-frame retrofit (labor, sealant tape, Title 24 docs, disposal). Whole-project bands: $3,000–$10,000 for typical 4–10 window jobs.

Vinyl retrofit
$900–$1,100
Valley tract homes, ADUs, rentals — the volume tier
  • Milgard Tuscany or Anlin Catalina retrofit
  • Double-pane Low-E with argon
  • U-factor 0.30, SHGC 0.23 (Title 24 LA)
  • Block-frame fin, butyl tape seal
  • Lifetime install warranty
Fiberglass retrofit
$1,100–$1,300
Hot west elevations — won't warp or chalk in LA sun
  • Marvin Elevate or Pella Impervia retrofit
  • Double-pane Low-E² with argon
  • U-factor 0.27, SHGC 0.22
  • Color-matched fin, factory-finished
  • Lifetime install warranty
Wood-clad retrofit
$1,250–$1,400
Higher-end Studio City / Sherman Oaks remodels
  • Andersen 400 or Marvin Ultimate retrofit
  • Double-pane Low-E² with argon
  • U-factor 0.26, SHGC 0.22
  • Aluminum-clad exterior, real wood interior
  • Lifetime install warranty
What's included

What retrofit includes.

The decision framework

Retrofit vs full-frame: how we decide.

Three questions answer it. First: how old is the home? Pre-1985 means original aluminum framing that's almost always corroded or out of square at the sill. We see this constantly on Burbank, Glendale, and Eagle Rock homes from the 1950s–70s — the aluminum looks fine until you push on it and the corner separates. Those are full-frame jobs every time. Post-1985 vinyl or aluminum framing in intact stucco is the retrofit sweet spot.

Second: what does the sill area look like from the inside? Paint bubbling, drywall stains, soft trim, or a musty smell within four feet of any window means moisture has found a path. Retrofit traps that path inside the wall — we have to open it up to find the source. If you've had a roof issue, a stucco crack repaired in the last decade, or sprinklers hitting the wall, we recommend full-frame on at least the affected elevations.

Third: do you care about the glass area? On a Porter Ranch or Northridge tract home with standard 36×48 windows, losing an inch on each side reads as a thicker frame — most homeowners don't notice after a week. On a mid-century Sherman Oaks home with a wall of windows facing the canyon, that same inch is the view. We do mockups with masking tape on the existing glass at the measure so you decide before you sign, not after install.

What other contractors miss

Six retrofit failure modes other contractors miss.

Retrofit looks easy, which is why it gets done wrong constantly. Every one of these is a callback we've fixed on someone else's install.

Five steps · zero surprises

From walkthrough to weatherproof. In writing.

Every step has a deliverable, a name, and a fixed date. If we miss a date, we credit you $250 — written into your contract.

01
Day 1
Consult
Free 30-min walkthrough. Moisture meter on every sill. We tell you retrofit-vs-full-frame before we leave.
02
Day 2–3
Measure
Laser-precise on-site by Theo or Marc. Glass-area mockup with masking tape so you see the loss.
03
Week 1
Order
Specs locked. Manufacturer order placed. Permit pulled (yes, retrofit needs one in LA).
04
Week 4–6
Install
Our W-2 crew. 1 day for most homes. Same-day weatherproof, butyl-taped, weep-cleared.
05
Week 7
Inspect
City final, manufacturer registration, lifetime warranty issued in your name.
Real installs

What customers wrote afterward.

★★★★★

"Got three retrofit quotes in Granada Hills. Two contractors said one day and didn't mention the glass loss. Theo brought painter's tape, mocked up the new frame on our existing window, and said 'this is what you'll see.' We went with him. Six Anlins, done by 4pm, no stucco touched."

P
Priya S. — Granada Hills
Yelp · 6-window retrofit
★★★★★

"1992 Burbank stucco home. Another contractor was ready to retrofit eight windows. Red Stag's moisture meter found the kitchen sill at 24% — there was a slow leak from the roof valley above. They stopped, recommended full-frame on that one, retrofit on the other seven. Found rot we never would have caught."

K
Kevin T. — Burbank
Google · Mixed retrofit/full-frame
★★★★★

"Glendale tract home, 2001 build, all original Milgard aluminum. We just wanted vinyl retrofits — fast and cheap. Crew showed up at 8, eight windows in by 5, butyl tape all visible before the trim went on. Final inspection passed first try. $9,200 all-in."

R
Rosa M. — Glendale
Houzz · 8-window retrofit
Honest answers

What every homeowner asks first.

01How much glass do I lose with a retrofit?
Roughly 1" on each side — about 8% of the daylight opening on a typical 36×48 window. We mock it up with masking tape on your existing glass at the measure so you can see the new sightline before you sign anything. On standard tract-home windows it reads as a slightly thicker frame; on big picture windows or sliders it's more noticeable.
02Can I retrofit a wood frame?
Almost never. Block-frame retrofit is designed for aluminum or vinyl frames with a flat fin to seal against. Wood frames don't have that geometry, and you can't reliably seal a vinyl retrofit fin to a wood jamb. If you have wood frames, the right answer is full-frame replacement — same wood interior, new sash and frame, proper flashing.
03What's the lifespan of a retrofit install?
The window itself runs 25–35 years (vinyl) or 35–50 years (fiberglass / clad wood). The retrofit seal is the limiting factor — done with butyl tape and polyurethane sealant, it's a 20–25 year detail. Done with silicone caulk only (the cheap way), it's 6–8 years before you start seeing leaks.
04Do I need a permit for retrofit windows?
Yes. LADBS treats any window replacement — retrofit or full-frame — as a permitted alteration. Title 24 compliance is required, CF1R/CF2R must be filed, and most LA cities want a final inspection. We pull the permit and meet the inspector; it's included in the quote, not an add-on.
05Can you tell if I have hidden water damage without removing the frame?
Partially. A pinless moisture meter through the drywall and stucco gives us a reading, and we look for paint bubbling, interior stains, soft trim, and exterior cracks near the sill. If anything's borderline, we recommend full-frame on that opening — once we seal a retrofit over wet framing, the damage accelerates and we won't see it until the wall has to come apart anyway.
06How long does a retrofit job take?
Most 6–10 window homes finish in one day. Larger projects (12+ windows) or homes with mixed retrofit and full-frame openings run 1.5–2 days. Every opening is fully sealed before the crew leaves — we don't leave anything tarped overnight.
07Will retrofit hurt my home's resale value?
Not if it's the right call for the home. Buyers and inspectors in the Valley expect retrofit on post-1985 stucco tract homes — it's the standard. Where it hurts resale is when retrofit was used on a pre-1985 home with hidden damage, or when the install is visibly bad (caulk-only seals, gaps at the corners). A clean, butyl-taped, code-compliant retrofit shows as a positive on inspection.
08Do you do retrofit and full-frame on the same project?
Often. About a third of our jobs are mixed — retrofit on the bedroom side where everything's intact, full-frame on the kitchen wall where there's a moisture issue. Same crew, same week, single contract. We price each opening on its merits, not the project as a single tier.
Service area

Retrofit window installation across Los Angeles.

Strongest in the Valley and east-side stucco belt — same crew, same trucks, same 45-minute drive if a sealant joint pops in 2031.

Ready to scope your retrofit?

No deposit to quote. Moisture meter on every sill at the consult. Quote within 48 hours of measure. We'll tell you if retrofit is wrong for your home — even if you wanted to hear yes.

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