Home Addition Planning Checklist

Everything you need to do before breaking ground, organized by timeline. Use this alongside your cost estimate to stay on track and avoid the most common planning mistakes.

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Permit timing is the most common surprise. Some cities process permits in 2 weeks. Others take 3 months. Call your local building department before you commit to any contractor timeline.

13–6 Months Before Breaking Ground

  • Define your project scope — addition type, square footage, and must-have features
  • Set a realistic budget with a 15–20% contingency built in
  • Research local zoning rules and setback requirements (call your building department)
  • Decide: hire an architect, a design-build firm, or go with contractor-drawn plans
  • Start researching contractors — ask neighbors, check local Facebook groups, use NAHB's directory
  • Pull your credit and check HELOC/home equity loan rates if you plan to finance

22–3 Months Before

  • Get at least 3 written contractor bids (same spec sheet for all 3)
  • Verify each contractor: license number, insurance certificate, BBB rating
  • Call 2–3 references from each contractor's last 3 jobs
  • Have your attorney or a trusted contractor review the contract before signing
  • Lock in financing — HELOC draws, construction loan, or cash reserve plan
  • Submit permit application with architect drawings (municipality-specific timing varies)

31 Month Before

  • Confirm permit approval date with your building department
  • Walk the site with your contractor and finalize material selections
  • Confirm utility mark-outs (call 811 at least 3 business days before any digging)
  • Establish a payment schedule — never pay more than 10% upfront in most states
  • Set up a project communication method with your contractor (weekly check-in day/time)
  • Arrange temporary housing if the addition affects a major living area

4During Construction

  • Keep a project log — date, what was done, any concerns raised
  • Take photos weekly from the same angles (valuable for insurance and disputes)
  • Never pay ahead of the agreed milestone schedule
  • Request copies of all sub-contractor insurance certificates before they start work
  • Schedule municipal inspections promptly — delays here stall everything downstream
  • Document all change orders in writing before work begins

5Final Punch List & Close-Out

  • Walk through with contractor before final payment and note every incomplete item
  • Confirm all municipal inspections passed and certificate of occupancy is issued
  • Collect all warranty documents (roofing, windows, HVAC, appliances)
  • Get lien releases from general contractor and all major subcontractors
  • Update your homeowner's insurance policy to reflect the increased square footage
  • Notify your county assessor — your property tax basis will change

This checklist reflects typical project requirements in the US. Local codes, lender requirements, and contractor practices vary. Always verify specific requirements with your local building department and licensed professionals.