Lake Oswego Home Addition Contractor

Running out of space in your home doesn’t mean you need to move. A thoughtfully designed home addition allows you to expand your living space while preserving the location, neighborhood, and character you already love.

At Lamont Bros., we help Lake Oswego homeowners design and build high-quality home additions that seamlessly integrate with the existing structure, both aesthetically and structurally.

Whether you're adding square footage for a growing family or creating specialized living space, our design-build process ensures a cohesive and efficient project from start to finish.

Free Download: Home Addition Buyer's Guide Schedule a Consultation

What Does a Home Addition Contractor Do?

A home addition contractor manages the design, planning, and construction of new living space added to your existing home. Unlike piecemeal remodeling, a professional design-build contractor ensures your addition blends seamlessly with your home’s layout, systems, and architectural style.

Common home additions in Lake Oswego include:

Primary suite additions
Kitchen expansions
Second-story additions
ADUs and guest suites
Home offices and flex spaces
Garage conversions and expansions

Why Build a Home Addition in Lake Oswego?

Lake Oswego homeowners often choose additions as a strategic alternative to moving in a competitive, high-value housing market.

Top reasons include:

Increasing livable square footage without relocating
Adapting the home for changing lifestyle needs
Creating multigenerational living solutions
Enhancing property value in a premium market
Customizing the home to fit long-term plans

Types of Home Additions We Do in Lake Oswego

The Lamont Bros. Design & Construction team designs and builds a range of additions in Lake Oswego, such as bathroom and kitchen additions, primary suite additions, ADUs and guest spaces, garage and basement conversions and more.

Main-Level Additions

Expand your footprint to create larger kitchens, living rooms, or new functional spaces that improve flow and usability.

Second-Story Additions

Add significant square footage without expanding your home’s footprint—ideal for maximizing smaller lots in Lake Oswego.

Primary Suite Additions

Create a private retreat with a spacious bedroom, en suite bathroom, and walk-in closet.

ADUs & Guest Suites

Add independent living spaces for guests, rental income, or multigenerational living.

Garage Conversions & Expansions

Transform underutilized garage space or expand it into livable square footage.

How Much Do Home Additions Cost in Lake Oswego?

The cost of a Lake Oswego home addition will range from around $100,000 to $400,000+, depending on the size of the addition, structural requirements, and the level of interior finishes.

Projects that involve major structural changes, such as second-story additions or large kitchen expansions, usually fall on the higher end due to engineering, roofing adjustments, and system upgrades.

What Factors Influence the Cost of a Lake Oswego Home Addition?

The factors that influence the cost of a home addition include structural engineering requirements, foundation work, roof modifications, plumbing and electrical upgrades, finish quality, and custom design features.

The most accurate pricing comes from a feasibility consultation and on-site evaluation where we review your home’s structure, layout, and project goals.

Typical Lake Oswego Home Addition Cost Ranges

Small bump-out addition: $100,000 – $175,000
Kitchen or living room expansion: $175,000 – $275,000
Primary suite addition: $200,000 – $350,000
Second-story addition: $250,000 – $400,000+

Want a personalized estimate? Try Our Home Addition Cost Calculator

Why Choose Lamont Bros. as Your Lake Oswego Home Addition Contractor?

Lamont Bros. Design & Construction has been remodeling high-end homes in the Portland metro area since 2008. With a 4.8/5 star average customer rating, we're one of Lake Oswego's top design-build contractors.

Our design-build process means there are no financial surprises once we've nailed down the project specifications. Here's why Lake Oswego homeowners choose Lamont Bros. for their home remodeling projects:

Proven design-build expertise
Deep experience with complex additions and structural projects
Transparent pricing and process
Strong understanding of Lake Oswego zoning and permitting
Commitment to craftsmanship and client experience

Lamont Bros. Design & Construction

Home Addition Portfolio

These additions across the Portland metro area include second-story additions, basement build-outs, built extra bathrooms, and more.

More Projects

Addition

Hillsboro Second-Story Addition

Lake Oswego | Home Addition Construction

Frequently Asked Questions

How much does a home addition cost in Lake Oswego?

Home addition costs in Lake Oswego typically range from $100,000 to $400,000+, depending on size, structural complexity, and finish level.

Lamont Bros. Design & Construction provides detailed, design-driven estimates to align scope and budget early.

Try our Home Addition Cost Calculator

How long does a home addition take from start to finish?

Most home additions take 6–10 months for construction, plus 2–4 months for design and permitting; Lamont Bros. Design & Construction manages the full timeline to reduce delays and keep the project on track.

Can I live in my home during a home addition project?

In many cases you can remain in your home, but it depends on how the addition ties into existing living areas; Lamont Bros. Design & Construction plans phasing and site logistics to minimize disruption when occupancy is possible.

What type of home addition adds the most value?

Primary suite additions, kitchen expansions, and well-designed second-story additions typically deliver the strongest resale value; Lamont Bros. Design & Construction prioritizes layouts and features that improve both daily livability and long-term ROI.

Do I need permits for a home addition in Lake Oswego?

Yes, all structural home additions require permits and must meet Lake Oswego zoning and building codes; Lamont Bros. Design & Construction handles permitting, drawings, and coordination with local authorities.

Is a second story addition a good option for my property?

Second-story additions are ideal for maximizing space on smaller lots, though they involve more structural engineering and cost; Lamont Bros. Design & Construction evaluates feasibility, structure, and budget to determine if it’s the right approach.

Why hire a design-build contractor for a home addition?

A design-build contractor unifies design, budgeting, and construction under one team, reducing risk and misalignment; Lamont Bros. Design & Construction delivers a cohesive process that improves accuracy, communication, and final results.

Award-Winning Design

Multi-award-winning Portland design-build firm, including the NARI Remodeler of the Year awards and Houzz Best Service every year since 2016.

Great Reviews

Excellent reviews across Google, Houzz, and Yelp demonstrate consistent client satisfaction.

Deep Expertise

Over nearly 20 years we've completed 850+ remodeling projects in the Portland metro area.