Where addition budgets break
Roof tie-ins, foundation matching, and load-bearing wall removal are the three line items that most often exceed the original quote. Ask specifically how each is priced before signing.
- • A second-story addition costs 15–30% more than a ground-level one.
- • Check setback and lot-coverage limits before you draw anything.
- • Bumping out under an existing roofline is the cheapest square footage you can add.
FAQ
How much does a 20x20 addition cost?
A 400 sq ft addition typically runs $80K–140K depending on finish level, plus $15K–25K if it includes a full bathroom.
Is an addition cheaper than moving?
Often yes once you account for agent commissions, closing costs, and a higher mortgage rate on a new loan. Compare the addition budget against 8–10% of your home's value in transaction costs.
Do I need a permit for a room addition?
Almost always. Any change to the footprint, structure, or electrical service requires permitting and inspection, and unpermitted square footage can fail an appraisal at resale.
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