Most home additions in Redmond run $200 to $400 per square foot for finished living space, depending on complexity, finishes, and whether you need foundation work or a second-story framing package. A modest 288 square foot addition (12×24) typically lands between $58,000 and $115,000 all in. A 144 square foot addition (12×12) generally runs $29,000 to $58,000. Those ranges assume standard Redmond permit fees, typical site conditions, and mid-grade finishes. Wet rooms like bathrooms or kitchens added inside the addition push costs toward the higher end. We give you a fixed-scope proposal before any work starts so there are no surprises.

Building out, meaning a ground-floor addition, is usually less expensive per square foot than building up. A second-story addition requires engineering, temporary roof work, reinforcing existing walls and foundations to carry the load, and more disruption to your living space during construction. That said, if your Redmond lot is tight or sits in a critical areas buffer near wetlands or steep slopes, building up may be your only practical option. We look at your specific lot and foundation before recommending a direction, because the cheaper option on paper is not always the cheaper option for your property.

The 30% rule is a general guideline that says you should not spend more than 30% of your home's current market value on a renovation or addition if you want a reasonable chance of recouping the cost at resale. In Redmond, where median home values are high, that 30% ceiling gives you meaningful room to work with. The guideline matters most if you are adding space purely for resale. If you are adding a bedroom, an ADU, or a larger kitchen because your family needs it and you plan to stay for 10 or more years, the math changes and the addition often makes clear sense regardless of the 30% threshold.

From signed contract to move-in, a typical single-story addition in Redmond takes 4 to 8 months. Permit review through the City of Redmond currently runs 6 to 12 weeks for most residential addition permits, and that happens before any shovels go in the ground. Construction on a 400 to 600 square foot addition usually takes 10 to 16 weeks once permits are approved. Larger additions, second-story work, or projects with significant site prep add time. We schedule the permit submittal before mobilizing trades so you are not paying crews to wait.

Yes. Any addition that adds conditioned living space in Redmond requires a building permit from the City of Redmond. That includes foundation work, framing, electrical, plumbing, and mechanical. Skipping permits creates real problems: unpermitted additions can stall or kill a home sale, and lenders and inspectors flag them. Bayside handles the full permit application and works directly with the City of Redmond building department. You do not need to manage that process yourself.

The most common projects we see in Redmond are primary suite additions, extra bedroom additions for growing families, kitchen expansions, and ADUs (accessory dwelling units) built as detached or attached structures. ADUs in particular have strong demand in Redmond right now because they can house a family member or generate rental income. We also do bump-outs, which are smaller extensions that expand a specific room, usually a kitchen or dining area, without building a full foundation addition. The right type depends on your lot, your goals, and your budget.

Lot coverage limits, setbacks, and critical area regulations all affect what you can build. Redmond zoning typically limits impervious surface and total lot coverage, and many Redmond properties have setback requirements that restrict how close a structure can sit to property lines. Some lots near Marymoor Park or along the Bear Creek corridor have additional environmental buffers. Before you commit to a design, we review your parcel data and site conditions so you know what is actually buildable on your specific property, not just what is theoretically possible.