On Budget. On Schedule. No Surprises.
Home Additions & Conversions in Portland
Planning an addition or ADU in SE Portland, Lake Oswego, or Happy Valley? Looking for a licensed design-build firm you can trust?
Tortoise Construction builds home additions, second-story additions, ADUs, and garage conversions across SE Portland, NE Portland, Lake Oswego, and the Portland Metro. Additions are among the most complex remodels: permits, structural work, and trade coordination are exactly where budgets and timelines tend to slip.
We don't start construction with a rough estimate. Our 5-step pre-construction process locks every finish, every trade price, and every scope detail, including permits and structural plans, before demo begins. You get a fixed price backed by our No Change Order Guarantee.
Start with a free Project Risk Snapshot™, a 30-minute call that gives you a realistic budget, your project's top risks, and an honest timeline before you commit. See our two-level deck addition in West Hills.
What Portland homeowners say
A great kitchen remodel starts with the right team.
Some clients come to us needing better storage and flow. Others are ready for a complete kitchen overhaul. Wherever you’re starting, we can help bring your ideas to life.
Every detail is handled with care and precision, so your finished kitchen feels both beautiful and functional.
Additions Conversions Portfolio
Why Expand with Tortoise Construction
No Change Order Guarantee
You know the price before demolition starts. Every finish, every trade, and every cost, including permits, is locked in during pre-construction. No surprise invoices, ever.Fixed Price Before Construction
We don't begin your addition until your budget is exact. Every material, trade price, and permit cost is confirmed before we break ground.5-Step Pre-Construction Process
From your measure meeting through trades day confirmation, our structured process narrows your budget to a fixed price, so construction starts with total certainty.
Additions & Conversions FAQs
What types of additions and conversions do you handle?
We specialize in a wide range of projects, including second-story additions, family room expansions, custom in-law suites, garage conversions, and accessory dwelling units (ADUs). Whether you need more space for a growing family, a dedicated home office, or a multi-generational living arrangement, we design and build solutions tailored to your needs.
Will my addition or conversion look like it belongs with the rest of my home?
That's always our goal. We take a tailored approach to every project, designing each addition or conversion to blend seamlessly with your home's existing structure, layout, and style, both visually and functionally. We don't do cookie-cutter work; every project is unique to the home and the homeowner.
Do you handle permits and project management, or is that left to the homeowner?
We take care of it all. From permits and planning to trade coordination and timeline management, we handle the behind-the-scenes logistics so you don't have to. Our goal is to keep your project on track, on budget, and as stress-free as possible from start to finish.
What areas do you serve for additions and conversions?
We serve homeowners across Portland, Lake Oswego, Happy Valley, and the surrounding communities. Our team provides full-service project management throughout the greater Portland area, keeping you informed and involved every step of the way.
How do we get started on an addition or conversion project?
The first step is a free Project Risk Snapshot™, a 30-minute call where we identify the biggest risks to your budget and timeline before you commit. From there, our 5-step pre-construction process delivers a fixed price backed by our No Change Order Guarantee. Call 971-800-0150 or book through our website.
Start Your Addition or Conversion Project Today
Your free Project Risk Snapshot™ is a 30-minute conversation with Portland's no-surprise remodeler. You'll walk away with a realistic budget for your addition or conversion, your project's top risks, and an honest timeline, before you've signed anything or spent a dollar.