Home Additions
Home Addition in Flagstaff, AZ
Adding square footage is one of the most complex residential projects a homeowner can undertake. It involves foundation work, structural integration with an existing building, and mechanical/electrical coordination across old and new. We've done it enough to know where it goes wrong.
Types of Additions
What we handle
We take on the full scope of residential additions, from straightforward room additions to more complex ADUs and structural expansions.
Addition types
- Room additions (bedroom, living space, office)
- Garage conversions to living space
- Attached ADUs (accessory dwelling units)
- Master suite expansions
- Sunroom and four-season additions
Key considerations
- Integration with existing structure
- Foundation matching and tie-in
- Roof tie-in and weatherproofing
- Matching exterior materials
- HVAC extension or new zone
- Permit and setback compliance
Our Process
How it works with Stronghold
Discovery & Design
We walk the space, talk budget, and figure out what you actually want.
Detailed Quote
Line-itemized, written before any work starts.
Permitted Build
Permits pulled, inspections scheduled. Crew shows up on time.
Walkthrough & Punch
We go through every item together before we call it done.
Cost Guidance
What does a home addition cost in Flagstaff?
Home additions in Flagstaff typically run $150–$250 per square foot depending on complexity. A simple 400 sq ft room addition might run $65,000–$100,000. A fully finished suite addition with bathroom adds to that.
The structural complexity of integrating with an existing home is where most of the cost variation lives.
These are ranges, not quotes.
Every addition is different. The only way to get a real number is a site walk and a look at your existing structure. We don't charge for that.
Schedule a Site Walk →Common Questions
Home addition FAQ
Do home additions require permits in Flagstaff?
Yes, always. Structural additions, electrical, plumbing, and mechanical work all require permits through the City of Flagstaff or Coconino County.
How long does a home addition take?
A typical addition takes 4–8 months from permit application to completion, depending on size and complexity.
Can you match the existing exterior materials?
We do our best and usually succeed, but exact matches on older siding or roofing materials aren't always possible. We'll be straight with you about what's achievable before the project starts.
Does adding square footage affect my property taxes?
Adding permitted square footage typically increases your assessed value, which can affect property taxes. We'd encourage you to check with your assessor; it's worth knowing before you build.
Get Started
Ready for an honest quote on your addition?
We'll do a site walk, look at what's actually needed, and put together an itemized written quote. No lump sums, no surprises. We respond within one business day.