A Homeowner's Strategic Guide

To Additions in Washington State

The Core Dilemma: Add On or Move?

The decision is more than just square footage. In Washington's market, retaining your low-interest mortgage is a powerful financial incentive to remodel, often outweighing the high transactional costs of moving.

Typical Addition Cost

$100k - $300k+

A major upfront investment into your existing property.

Total Transactional Cost to Move

8% - 16%

Of home values, plus moving expenses, and a new, higher mortgage rate.

The Deciding Factor

Your Mortgage Rate

Giving up a sub-4% rate can cost tens of thousands over the life of a new loan.

What's the Return on Your Investment?

Financial ROI: Cost Recouped at Resale

While no project offers a 100% financial return, exterior upgrades and minor kitchen remodels consistently provide the highest value.

The "Joy Score": A Measure of Happiness

Beyond finances, NARI's "Joy Score" quantifies the satisfaction a project brings. These projects consistently score a perfect 10/10.

New Primary Bedroom Suite ★★★★★★★★★★
Kitchen Upgrade ★★★★★★★★★★
New Roofing ★★★★★★★★★★

Decoding the "Seattle Premium": Why Costs Are Higher

Project Budget Breakdown

In high-cost areas, foundation, structural, and system upgrades are major "budget busters" that drive up the total project cost.

Key Cost Drivers in the Puget Sound

High Labor Costs

A competitive market for skilled tradespeople commands premium wages.

Stringent Building Codes

Rigorous energy (WSEC) and seismic requirements add significant expense to materials and engineering.

High-End Finish Expectations

High property values create a market expectation for premium materials to match.

The ADU Opportunity: A New Era in Housing

Recent state laws (HB 1337) have revolutionized Accessory Dwelling Units, making them powerful financial assets. However, a "regulatory lag" exists as local cities slowly update their codes. Always verify with your local jurisdiction.

Regulation
State Mandate
King & Snohomish
Tacoma & Pierce
Max ADUs Allowed
2
Owner Occupancy Req?
No
Can Be Sold Separately?
Yes

✓ = In Compliance | ✗ = Not Yet in Compliance with State Law

The Critical Final Step: Vetting Your Builder

Using the free Washington L&I "Verify a Contractor" tool is the single most important action you can take to protect your investment. Before you sign anything, follow this non-negotiable checklist.

1. Active Registration

2. Sufficient Bond

3. Liability Insurance

4. Workers' Comp

5. Clean History