Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
CWS Construction in Los Altos, CA | Rowan Construction Group Mountain View
Rowan Construction Group Mountain View provides independent CWS window, door, and siding service across Los Altos for teardown-rebuilds, whole-home renovations, and ADU additions. We’re not a CWS-authorized dealer - we’re the crew that other contractors call when a CWS installation on adobe clay soil starts showing cracks after the first winter. For CWS service in Los Altos, call (669) 215-4852 to schedule your free estimate with a written scope and flat price before any work begins.
Why Los Altos Residents Choose Us for CWS Service
We’ve installed and serviced CWS windows and doors on Los Altos teardown-rebuilds since the first wave of $3-million-lot sales accelerated around 2015. That work has taught us what CWS’s own documentation won’t tell you: the 5000 Series fiberglass nailing fin that performs fine in Mountain View’s more stable soils will crack in Los Altos’s expansive adobe clay unless you spec a reinforced stainless fin and flexible membrane flashing from the start.
Grant Rowan grew up in Beverly Hills and learned the trade at Los Angeles Trade-Technical College, spending two years on framing, concrete, and finish work before he ever collected a paycheck on a real site. He’s been in construction over two decades now. In Los Altos, he and our crews have worked from the downtown blocks near University Avenue out to the larger lots off Foothill Expressway. We show up on time, keep a clean site, and write scopes that don’t leave room for invoice surprises. Our CWS sales & service covers the full product line with honest comparisons - because we’re independent, we don’t push factory warranty terms that won’t fit your custom build.
Every visit includes a documented photo record as standard. Calls are answered by a live person 24/7. Our technicians are background-checked and uniformed. Under Clause 1 of the Haven Standard, the price is written before anyone picks up a tool.
Common CWS Construction Problems We Solve in Los Altos

- Vinyl frame warping and seal failure on south- and west-facing elevations. Los Altos’s intense summer sun hits hard on newly cleared teardown lots where mature shade trees have been removed. The CWS 3000 Series vinyl windows we see on 1960s ranches weren’t engineered for that exposure. We replace failed units with heat-stabilized glass packages or spec the 5000 Series fiberglass on new builds.
- Sliding glass door rollers corroding and tracks binding with adobe clay dust. The CWS 9000 Series sliding doors perform well once the house is finished, but during phased construction on Los Altos rebuilds, unpaved site access tracks fine clay dust directly into the roller mechanism. We clean and repack tracks during construction-phase service calls, then install sealed stainless rollers for the final walkthrough.
- Fiberglass nailing fin cracking from differential foundation movement. This is the one that costs homeowners the most if missed. Los Altos’s post-tension slab foundations engineered for expansive clay still experience micro-movement between wet and dry seasons. Standard CWS 5000 Series nailing fins crack at the corners; water gets in; stucco separates. We’ve developed a reinforced fin detail with flexible membrane flashing that eliminates the callback.
- Composite siding delamination at butt joints on north-facing walls. CWS Custom Composite Siding needs proper gaping and rain-screen detailing to survive Los Altos’s winter rain cycles. North walls with limited drying time are the failure point. We inspect existing installations for moisture wicking and rebuild joints with correct drainage plane geometry.
- Window schedule conflicts with Heritage Tree Ordinance root-zone exclusions. A standard CWS window layout that passed in Sunnyvale gets rejected in Los Altos when a protected valley oak’s root zone pushes the building envelope inward. We redraw the schedule with smaller ganged units or relocated openings - before the planning department sends it back.
Before
AfterCWS Service in Los Altos: What Local Conditions Mean for Your Equipment
Los Altos sits on some of the most expensive bare dirt in California. That economics drives a construction profile you won’t find in neighboring cities: systematic teardown of 1950s-1970s ranch homes and replacement with 4,000-5,000 square foot custom residences for tech-industry buyers who expect smart-home integration and premium finishes. Many of these projects include our Kitchen Remodeling in Los Altos as part of the full custom build. For CWS installations, this market reality creates two constraints that generic Bay Area CWS pages ignore entirely.
First, the adobe clay soils. The Santa Clara Valley’s expansive clays swell with winter rain and shrink through the dry summer, cycling foundation stress that standard CWS installation details don’t address. Second, and more specific to Los Altos, the Heritage Tree Ordinance. Protected valley oaks and other heritage specimens require city-approved arborist oversight and root-zone exclusion zones. We’ve seen foundation footprints forced inward by fifteen feet or more to preserve a single mature oak. That redesign changes every window placement and sizing decision. A CWS window schedule that worked in Mountain View or Sunnyvale will not pass Los Altos planning once root zones are plotted. We know this because we’ve redrawn those schedules, resubmitted to planning, and kept projects on schedule. Our Los Altos service area coverage includes permit coordination with the city’s planning department - not as an upsell, but as standard project management.
CWS Models & Products We Service in Los Altos

We work across the full CWS residential line: the CWS 3000 Series Vinyl Windows common on original Los Altos ranch stock; the CWS 5000 Series Fiberglass Windows we specify for most new builds and whole-home replacements; the CWS 9000 Series Sliding Glass Doors used for indoor-outdoor transitions on modern teardowns; and CWS Custom Composite Siding for exterior envelope finishes.
Our parts approach is straightforward. We stock OEM CWS glass units, rollers, and weatherstripping for warranty-eligible replacements. When lead times stretch or a profile discontinues - which happens more than CWS advertises - we source equivalent-gauge aftermarket vinyl and fiberglass sashes that match the original thermal and structural specs. For windows still structurally sound, we replace hardware and glazing. When frames have warped or seals failed repeatedly, we recommend full-unit replacement before the next rainy season. No work proceeds without a signed change order and a written price.
CWS Service Pricing in Los Altos
These are the ranges we see on Los Altos CWS projects, based on 2024-2025 market pricing. Every quote is flat, written, and includes a documented scope - no call-for-pricing, no open-ended allowances.
| Service | Typical Range in Los Altos |
|---|---|
| Window Replacement (per unit average) | $4,500 - $15,000 |
| Impact Window Installation (whole-house average) | $8,000 - $25,000 |
| Home Addition (structural shell + CWS windows) | $45,000 - $130,000 |
What drives cost: unit size, glass package (dual-pane standard, triple-pane or laminated impact glass upgrade), whether the opening needs structural reframing for a different size, and exterior finish repair - stucco, siding, or trim - after window replacement. Foundation work adds cost only if we’re also correcting settlement damage.
Our free estimate includes a full inspection, photo documentation of existing conditions, and a written scope with line-item pricing. Call (669) 215-4852 to schedule - estimates are free, and we offer a free second opinion on any competitor’s written quote.
Serving Los Altos, CA - Our Local Coverage Area

We’re based in the Los Altos area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - CWS Construction in Los Altos
Yes. The expansive adobe clay beneath most of Los Altos swells and shrinks seasonally, stressing window-to-wall connections. We specify reinforced stainless nailing fins and flexible membrane flashing on CWS 5000 Series fiberglass units - details that standard installation guides don’t require but that prevent the corner cracking we’ve documented on standard installations. Call (669) 215-4852 for an exact specification on your foundation type; estimates are free.
Yes, with attention to threshold drainage and construction-phase protection. The CWS 9000 Series sliding doors meet California Title 24 energy requirements when specified with the right glass package. On Los Altos ADUs, we detail the threshold for the clay subgrade’s moisture behavior and protect rollers during construction to prevent the dust contamination that causes early binding. For ADU projects that also need wet-area updates, we coordinate with our Los Altos Bathroom Remodeling team to keep schedules aligned. Call (669) 215-4852 to review your ADU plans.
Replace the insulated glass unit if the frame is square and the hardware operates smoothly; replace the entire window if the frame has warped, the sash doesn’t seal, or you’ve already had glass replaced once and it fogged again. Los Altos’s sun exposure on unshaded south elevations accelerates repeat seal failure. We inspect, photograph, and give you both options with written prices. Call (669) 215-4852 to schedule.
It can. Protected valley oaks and other heritage trees trigger root-zone exclusion zones that may push your building envelope inward, forcing smaller or relocated window openings than your original design specified. We coordinate with Los Altos planning and arborist requirements during the design phase to avoid redesigning your CWS window schedule after permit submission. Call (669) 215-4852 before you finalize plans.
Yes, when specified with the correct glass package and installation details. CWS 3000 and 5000 Series windows with low-E coatings and argon fill meet or exceed Title 24 prescriptive requirements. For Los Altos projects pursuing green building certification, we document U-factor and SHGC values in the written scope so your rater has the paperwork. Call (669) 215-4852 for specification details matched to your permit path.
Service Areas Near Los Altos

We run CWS service calls from our Mountain View base across the central Peninsula. Regular CWS service in Mountain View covers downtown and the San Antonio corridor. CWS service in Sunnyvale handles the Lawrence Station and Ponderosa areas. We also work in Palo Alto, Los Altos Hills, and the Stanford vicinity - same written-price standard, same documented photo record on every visit.
Book Your CWS Service in Los Altos Today
Call (669) 215-4852 to schedule your free CWS estimate in Los Altos. We’ll inspect your existing installation or review your new-build plans, document conditions with photos, and deliver a written flat price with scope before any work starts. Measure twice, write it down, then build it that way.
Written by Grant Rowan, Owner at Rowan Construction Group Mountain View, serving Los Altos since 2007.







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