Now covered in more depth
Adding a bedroom is one of the most common reasons Seattle homeowners call an architect. There are several ways to do it, each with different costs and complexity. Here is a complete guide.
Option 1: Convert Existing Space
The most affordable path. Converting a den, bonus room, or large closet into a bedroom. To legally count as a bedroom, the room needs an egress window (5.7 sq ft opening), a closet, and minimum 70 sq ft floor area with 7 ft ceiling height.
Cost: $10,000 to $35,000 depending on whether egress work is needed.
Option 2: Finish a Basement or Attic
Converting unfinished basement or attic space adds a bedroom without expanding the footprint. Basement bedrooms require egress windows. Attic bedrooms require adequate headroom (7 ft over at least half the floor area).
Cost: $25,000 to $70,000.
Planning a project?
Want a number for your addition?
Send David the address and a few lines about what you want. The first feasibility check is free and usually takes about a day: what the site and the code are likely to allow, and what to check first.
Architect since 1996, member of the AIA and NCARB. Three Masonry Excellence Awards for commercial projects; the Carr residence was featured in Above The Lake and Lux magazines.
Option 3: Build an Addition
A room addition adds a bedroom at grade or as part of a second story. This is the most expensive but adds the most value and flexibility.
Cost: $80,000 to $200,000 for a bedroom and bathroom suite.
Option 4: ADU for a Separate Bedroom Suite
If you need a private guest or in-law space, an ADU provides a full separate living unit. See our ADU design service.
Which Requires a Permit?
Any option involving structural changes, new egress windows, or new square footage requires a building permit. Simple conversions of already-conforming rooms may not.
