Home Addition in Mountain View
Custom Home builds home additions in Mountain View at $450-$650 per square foot. Whether you need a second-story addition, ground-floor expansion, or bump-out, our two-phase process delivers 3D visualization and itemized pricing before construction starts.
How much does a home addition cost in Mountain View?
Home additions in Mountain View typically cost $450-$650 per square foot in 2026. A 500 sqft addition ranges from $225K to $325K. Custom Home's design phase locks in your exact cost before construction starts.
Why Expand Your Mountain View Home
For Mountain View homeowners who love their neighborhood but need more space, a home addition is often more practical than buying a larger home. You keep your location, your neighbors, and your established landscaping. Silicon Valley’s tech-driven economy supports strong demand for modern, energy-efficient residences.
Custom Home designs and builds home additions with the same two-phase process we use for custom homes. You see the complete addition in 3D and receive itemized pricing before construction begins.
Types of Home Additions We Build in Mountain View
Second-Story Additions
Double your living space by building up rather than out. Second-story additions are ideal when lot coverage limits prevent ground-floor expansion. Custom Home’s structural engineers evaluate your existing foundation to determine what reinforcement is needed.
Ground-Floor Room Additions
Extend your home’s footprint with new bedrooms, family rooms, or home offices. Ground-floor additions integrate with your existing layout and maintain single-level living, which is especially valued in Mountain View.
Bump-Outs and Extensions
Smaller expansions that make a significant difference: extend your kitchen, enlarge a bathroom, or add a sunroom. Bump-outs typically cost less and complete faster than full additions.
Structural Considerations for Mountain View Additions
Mountain View is located in a seismically active region, which means home additions must meet current seismic codes. Custom Home’s engineering team handles foundation evaluation, load-bearing wall modifications, and seismic design for every addition project. Whether you are adding a second story or expanding your footprint, structural engineering is included in our Phase 1 design process.
Mountain View Home Addition Permits
Mountain View’s Community Development Department processes residential building permits with typical plan review times of 4-6 weeks. New construction and major additions are subject to the city’s Residential Design Guidelines. The city offers electronic plan submission and online permit tracking through its development portal.
Custom Home manages the entire addition permitting process, including structural engineering review, plan submittal, and inspection coordination. Our experience with Mountain View’s requirements helps keep the approval process on track.
Pricing for Home Addition in Mountain View
Home addition costs in Mountain View typically run $450-$650 per square foot, similar to new construction pricing. Second-story additions may cost more due to structural reinforcement requirements. Custom Home's Phase 1 design process locks in exact pricing before construction begins.
Mountain View Permit Requirements
Mountain View's Community Development Department processes residential building permits with typical plan review times of 4-6 weeks. New construction and major additions are subject to the city's Residential Design Guidelines. The city offers electronic plan submission and online permit tracking through its development portal. Custom Home manages the full addition permitting process, including structural engineering review.
Home Addition in Mountain View: FAQ
How much does a home addition cost in Mountain View?
Home additions in Mountain View typically cost $450-$650 per square foot. A 400 sqft room addition generally ranges from $180K to $260K. Second-story additions may cost more due to structural reinforcement. Custom Home locks in exact pricing during Phase 1.
How long does a home addition take in Mountain View?
Home additions in Mountain View typically take 6-12 months from design to completion. Second-story additions require 8-14 months due to additional structural work. Custom Home's design phase ensures construction runs efficiently and on schedule.
What is the difference between a bump-out and a full addition?
A bump-out extends an existing room by a few feet, while a full addition creates entirely new enclosed space. Bump-outs are smaller in scope and cost, while full additions offer more design flexibility. Custom Home helps you determine the right approach during Phase 1.