Home Additions in Eugene, Oregon

Marty Mar Construction Inc designs and builds room additions, second-story expansions, and accessory dwelling units for homeowners across Eugene, Springfield, Cottage Grove, and Lane County. We match new construction to your existing home's materials, rooflines, and interior finishes — so the addition looks like it was always there.

Get a Free Estimate Call (541) 554-8181

Licensed & Insured Since 2007 Eugene & Lane County

Expand Your Space

What Types of Home Additions Does Marty Mar Build?

Marty Mar Construction builds bedroom additions, second-story expansions, bump-outs, garage conversions, attached ADUs, and sunroom enclosures throughout Eugene and Lane County. Each addition is structurally integrated with your existing home and designed to meet current Lane County building codes.

Marty Mar Construction Inc is a licensed Oregon general contractor based in Eugene, building room additions and home expansions across Lane County since 2007.

Adding square footage to an existing home in Eugene demands more precision than building from scratch. Your new addition has to tie into the existing roof structure, match siding profiles that may no longer be standard stock, and connect to plumbing and electrical systems that were designed for a smaller footprint. Get any of that wrong and you end up with a visible seam — inside and out — that drops your home's value instead of raising it.

We start every addition project with a structural assessment of your existing home. We evaluate foundation capacity, framing condition, roof tie-in angles, and utility routing before drawing a single line. That upfront work means fewer surprises during construction and a finished product that looks intentional, not bolted on.

Last updated: June 2026

Home addition construction project by Marty Mar Construction in Eugene, Oregon

Addition Types

Which Addition Type Is Right for Your Eugene Home?

The right addition type depends on your lot size, zoning setbacks, existing foundation, and how you plan to use the new space. Single-story additions are fastest and most affordable; second-story additions maximize square footage without expanding your footprint; ADUs create independent living quarters.

Room Additions

Bedrooms, offices, family rooms — ground-level expansions that tie into your existing foundation and roofline. 8-12 weeks typical.

Second-Story Expansions

Add living space above without expanding your lot footprint. Requires structural reinforcement of existing framing and foundation.

ADUs & Garage Conversions

Accessory dwelling units for rental income, aging parents, or home offices. Garage conversions are the most cost-effective option per square foot.

Our Process

How Does the Home Addition Process Work in Eugene?

Our home addition process follows four stages: structural assessment and design, permitting through Lane County, construction with weekly progress updates, and final inspection with walkthrough. Direct communication with Marty at every stage — no middlemen.

Assessment & Design

Evaluate your home's structure, foundation, and utilities. Review plans, confirm setbacks, and finalize the scope and budget.

Permits & Engineering

Pull Lane County building permits, submit structural engineering, and coordinate plan review with the building department.

Construction

Foundation, framing, roofing, mechanical rough-ins, insulation, drywall, and exterior finish — with weekly progress updates.

Finish & Inspection

Interior finishes, flooring, paint, fixtures, final county inspection, and a walkthrough to confirm everything meets your expectations.

Common Questions

What Do Homeowners Ask About Room Additions in Eugene?

Homeowners considering a room addition in Eugene typically ask about costs, permits, timelines, and whether the addition will match their existing home. Below are the questions we hear most — with direct answers from our team.

How much does a home addition cost in Eugene, Oregon?

Home additions in Eugene typically cost $200-$400+ per square foot depending on the scope, finishes, and structural complexity. A 400 sq ft bedroom addition generally runs $80,000-$160,000. We provide a detailed written estimate after assessing your home and project requirements.

Do I need a permit for a room addition in Lane County?

Yes. Any structural addition in Lane County requires a building permit, plan review, and multiple inspections. Marty Mar Construction handles all permitting through the County or City of Eugene, including structural engineering, setback calculations, and inspection coordination.

How long does a home addition take to build in the Eugene area?

Most room additions in Eugene take 8-16 weeks from permit approval to completion, depending on size and complexity. Second-story additions typically take 12-20 weeks. Rainy weather during Oregon's wet season can add 2-4 weeks to exterior phases — we plan for that upfront.

Can you match the addition to my existing home exterior?

Yes — that is a core part of what we do. We match siding materials, rooflines, trim profiles, window styles, and paint colors so the addition looks like it was part of the original build. Inside, we match flooring, baseboards, and ceiling heights for a seamless transition.

What types of home additions do you build?

We build single-room bedroom or office additions, second-story expansions, bump-outs for kitchens and bathrooms, garage conversions, attached ADUs (accessory dwelling units), and sunroom enclosures. Each project is designed to fit your home's footprint and Lane County zoning requirements.

Expand Your Home

How Do You Get a Free Home Addition Estimate?

Call (541) 554-8181 or fill out our online form. We'll schedule a site visit to assess your home's structure, review your addition plans, and deliver a detailed written estimate — no cost, no obligation.

Request Free Estimate Call (541) 554-8181