Double Your Space. Not Your Footprint.
Preserve your land while expanding your life. Our structural designers transform single-story homes into architectural estates with precision and luxury.
What Is a
Second Story Addition?
A second story addition is the process of constructing an entirely new floor on top of your existing home — expanding your square footage vertically rather than outward into your yard. For Westlake Village homeowners, this is often the most strategic path to gaining space without sacrificing outdoor living, pool areas, or setback compliance.
Unlike a simple room addition, a second story requires a comprehensive structural engineering assessment of your existing foundation, walls, and load-bearing elements. Many homes built in the 1980s and 1990s can support a full second story with targeted reinforcements.
At 4 Seasons Remodeling, our structural engineers and designers work as one in-house team. That means no third-party delays, no misaligned plans, and a final result where the new floor feels architecturally inseparable from the original home.
Their engineering team was incredibly thorough and professional. We never felt unsure about the structural integrity — they explained every step.
— Michelle K., High Country
Why Go Up
Instead of Out?
In Westlake Village, land is limited and yard space is sacred. A vertical expansion adds significant square footage without sacrificing your outdoor space.
Strong equity returns compared to lateral builds.
Your outdoor space remains untouched.
Avoid relocation costs and stay in your home.
Preserve Your Yard
No impact to outdoor living space.
No Setback Issues
Avoid zoning limitations.
Resale Value
Adds high-value square footage.
Stay Rooted
Upgrade without relocating.
What We Build Upstairs
Every second story is a blank canvas. These are the most popular configurations we design and build across the Conejo Valley.
The Engineering Process
The most common fear among Westlake Village homeowners: "Can my house actually hold a second story?" Our licensed structural engineers answer that question first — before a single nail is driven.
Foundation Assessment
Our structural engineer evaluates the existing foundation type and soil bearing capacity to identify what can carry the new weight.
Week 1–2Structural Engineering
Our in-house team produces stamped structural drawings—beam schedules and shear wall layouts—integrated with architectural plans.
Week 2–5Permit Filing
We manage all back-and-forth with the City of Westlake Village building departments. You never need to set foot in a permit office.
Week 4–8Framing & Construction
Approved plans in hand, our crew reinforces the structure and frames the new second story under strict inspection standards.
Week 8–18Finish Work
Luxury finishes are installed floor by floor. Final inspections close the permits—leaving you with a complete, clean-title home.
Week 14–22Why In-House Engineering Matters
Most contractors outsource structural work, creating delays and miscommunication. At 4 Seasons, our structural engineers and designers work in the same office for faster approvals and zero discrepancies.
Before & After
Hover each photo to reveal the transformation. Our completed second story additions across Westlake Village, Lake Sherwood, and North Ranch.
Local Permitting & Compliance
Navigating dual-jurisdiction permitting is one of the biggest project risks homeowners face. We handle every layer, in-house, from first submission to final sign-off.
Westlake Village operates its own Building & Safety department. Second story additions require a full plan check, including architectural, structural, and energy drawings stamped by a California-licensed engineer.
- Architectural & structural plan sets prepared in-house
- Grading and drainage documentation where required
- Energy compliance (CalGreen / Title 24) calculations
- Online submission + department liaison throughout review
Some properties sit in unincorporated territory where the county holds permitting authority. Our team routes the application correctly from the start to avoid refiling delays.
- Jurisdiction verification before design begins
- County DRP application prep for unincorporated parcels
- Coordination with Ventura County Fire Department
Most of Conejo Valley falls within High Fire Hazard Severity Zones. Additions trigger mandatory WUI hardening requirements under CBC Chapter 7A.
- Class A fire-rated roofing materials
- Ember-resistant vents (Vulcan or equivalent)
- Dual-paned tempered glass on new windows
- Non-combustible eave soffits and fascia
- ✓ In-house structural engineers
- ✓ Full permit application prep
- ✓ WUI compliance built-in
- ✓ HOA submittal packages
- ✓ CSLB License #982386
What Homeowners Say
About Going Up
"Their engineering team was incredibly thorough. We never felt unsure about the structural integrity — they walked us through every calculation."
"We went from a cramped 3-bedroom to a 5-bedroom home without losing a single inch of our backyard. The team handled everything seamlessly."
"Best investment we've ever made. My mother-in-law now has her own beautiful floor above us. Finished two weeks ahead of schedule."
"Navigating the permits in Thousand Oaks seemed impossible until we met this team. They know the building codes inside and out."
"The new second story looks like it was always part of the original house. The design integration is flawless—exceeded our expectations."
"Professional, clean, and respectful. We added 1,400 sq ft and our property value has skyrocketed. The best in the Conejo Valley."
"From the first architectural drawing to the final inspection, they were on point. They made a massive project feel easy."
"Adding a second floor was the best way to keep our garden while giving our kids their own space. Truly a life-changing renovation."
Your Investment Range
Second story addition costs in Westlake Village vary based on square footage, structural complexity, finish level, and permit requirements. Here's what most homeowners invest:
400–600 sq ft. Two bedrooms + shared bath. Standard finishes. Ideal for growing families needing functional space.
600–900 sq ft. Primary suite, additional bedrooms, en-suite bathrooms. Semi-custom finishes, engineered hardwood.
900+ sq ft. Full primary retreat, spa bathroom, built-ins, balcony, and architectural custom finishes.
All estimates include structural engineering and permitting. Schedule a site assessment today →
Answers to Your Top Questions
Spring Structural
Remodeling Credit
Navigating dual-jurisdiction permitting is complex, and the initial assessment is critical. We handle every layer, starting with an exclusive promotion applicable toward your structural engineering and feasibility study.
"Mention this exclusive promotional credit when scheduling your structural assessment for second-story additions."
Let's Build Your
Dream Second Story
Our structural engineer and design team are ready to evaluate your home and guide you through the process upward.
Discovery Phase
Tell us about your project
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