Room Additions

Whether your family has outgrown your floor plan or you need a dedicated home office, a room addition is one of the smartest investments you can make in your Sacramento home. At Keystone Building Services, we build bedroom additions, family rooms, home offices, sunrooms, and bonus rooms that look and feel like they were always part of the original house. Room additions are one of our preferred project types — and it shows in the finished product.

Room additions in Sacramento typically cost $350 to $400 per square foot, depending on the complexity of the project, the finishes you select, and the structural requirements involved. That includes everything: foundation work, structural engineering, framing, roofline matching, electrical, plumbing (if applicable), HVAC extension, drywall, flooring, trim, and paint. A 200 square foot bedroom addition, for example, would range from $70,000 to $80,000 — fully permitted and finished.

The hardest part of any room addition is making the new space blend with what is already there. That is where our experience matters. We match your existing roofline so the addition does not look tacked on. We match siding, paint, interior trim profiles, and flooring so the transition from old to new is invisible. We handle all foundation work, structural engineering coordination, and full permit applications through the City of Sacramento and surrounding jurisdictions. You get one contractor, one point of contact, and a finished addition that looks like it was built with the original home.

Seamless integration is our standard, not an upgrade. When we build a room addition, the goal is simple: no one should be able to tell where the original house ends and the new space begins. That means matching rooflines precisely, continuing existing flooring without visible transitions, and blending interior trim, paint, and texture so the addition feels like it was always there. Most contractors treat this as an afterthought. We treat it as the entire point.

With Keystone Building Services, you get a single contractor handling every trade. Foundation, framing, electrical, plumbing, HVAC, drywall, flooring, paint, and trim — all managed by Gerardo Diaz and his crew. No subcontractor finger-pointing, no gaps between trades, and no surprises. Gerardo Diaz is a licensed electrician with over 11years of construction experience, so your addition's electrical system is handled in-house with the same precision as everything else.

Every room addition we build is fully permitted and built to California building code. We handle all permit applications, plan submissions, structural engineering coordination, and required inspections. Your project is backed by California contractor license #1095766, a $15,000 bond, full insurance, and a BuildZoom score of 98/100.