Why Choose Lamont Bros. for Your Portland Home Addition?

A home addition affects far more than square footage. It must work with your existing structure, improve the way your home functions, and feel like it has always belonged there. That requires design, engineering, permitting, budgeting, and construction decisions to support the same plan.

Lamont Bros. brings those responsibilities together through one accountable design-build team. We help you evaluate the possibilities, understand the tradeoffs, and make informed decisions before construction begins. Then we carry the design through the build, reducing the gaps and surprises that can occur when homeowners must coordinate separate firms.

Explore our completed home additions to see how we have expanded Portland-area homes while respecting their existing character. When you are ready to discuss what could work for your home, schedule a consultation.

What Our Clients Say

 

How Much Do Home Additions Cost in Portland?

Home addition costs in Portland typically range from $100,000 to $400,000+, depending on size, structural complexity, and finish level. Second-story additions and kitchen expansions are generally more expensive due to engineering and mechanical integration.

Typical Portland 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+

What affects cost most?

  • Structural engineering requirements
  • Foundation work
  • Roof modifications
  • Plumbing & electrical upgrades
  • Finish quality and custom features

For an accurate estimate, a feasibility consultation and site evaluation are required.

Want a personalized estimate? Try Our Home Addition Cost Calculator

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See Why We're Portland's Favorite Home Addition Contractor

Building a custom home addition in Portland is made easy with our design-build process. 

 

Custom Portland Home Additions

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

Portland | Home Addition Construction

Frequently Asked Questions

How much does a 500 sq ft home addition cost in Portland?

A 500 square foot addition in Portland typically costs between $175,000 and $300,000, depending on structural complexity, finish level, and utility integration.

Kitchen and bathroom additions trend toward the higher end due to plumbing and cabinetry costs.

Is it cheaper to build up or build out in Portland?

Building out is often less expensive structurally, but it requires adequate lot space and setback compliance. Building up (adding a second story) avoids expanding the footprint but requires significant structural reinforcement. The most cost-effective option depends on lot size, foundation capacity, and zoning.

How long does a home addition take in Portland?

From design through construction, most home additions take 6 to 12 months. Permitting alone can take several weeks to a few months, depending on project complexity and city workload.

What's the difference between a home addition and an ADU?

A home addition expands your existing home and shares utilities and living space. An ADU (Accessory Dwelling Unit) is a separate, self-contained living unit with its own kitchen and bathroom. Portland has specific zoning regulations governing ADUs.

Do home additions increase property value in Portland?

Yes. Well-designed home additions often increase resale value, especially when adding bedrooms, bathrooms, or expanding kitchens. Return on investment depends on neighborhood market conditions and project quality.

Can you live in your home during an addition project?

In many cases, yes. However, for large structural projects like second-story additions, temporary relocation may be recommended for safety and efficiency.

What neighborhoods in Portland do you serve?

Lamont Bros. provides custom home additions throughout Portland, including neighborhoods such as Alameda, Alberta Arts District, Arbor Lodge, Beaumont-Wilshire, Boise, Brentwood-Darlington, Brooklyn, Buckman, Concordia, Creston-Kenilworth, Eastmoreland, Forest Heights, Goose Hollow, Grant Park, Hawthorne, Hillsdale, Irvington, Laurelhurst, Lents, Maplewood, Montavilla, Multnomah Village, Nob Hill, Overlook, Pearl District, Richmond, Sellwood-Moreland, St. Johns, Sunnyside, University Park, West Hills, and Woodstock.

In addition to serving Portland neighborhoods, we also complete home additions in surrounding areas including Beaverton, Lake Oswego, West Linn, Tigard, Tualatin, Milwaukie, Happy Valley, and other nearby communities throughout the greater Portland metro area.

Award-Winning Design

 A two-time 2026 National NARI Remodeler of the Year winner, plus Houzz Best Service every year since 2016 — award-winning design since 2008. 

Great Reviews

 4.7/5 from 97+ Google reviews, plus top ratings on Houzz and Yelp — consistent client satisfaction, verified. 

Deep Expertise

 18 years in business since 2008, 850+ completed remodeling projects, and licensed in Oregon (CCB #184500) and Washington (WA #LAMONBL820RR).