HomeDaddy AI · Infill Spec Build & Arizona HB 2720 ADU Construction Desk · ADRE #SA713873000
Ground-Up Spec Home, Detached Guest Casita (ADU) & Infill Lot Construction Analyzer
Advisor Takeaway (Stephen R. Mannenbach): Underwrite ground-up luxury infill spec builds in Arcadia (85018), Paradise Valley (85253), and North Scottsdale (85255 / 85262), plus detached guest casita (ADU) expansions under Arizona HB 2720 at up to 85% Loan-to-Cost (LTC) and 70% Loan-to-ARV (LTARV).
2026 Scottsdale & Phoenix Ground-Up & ADU Construction Benchmarks
| Construction Tier | Hard Cost / SqFt | Max Leverage (LTC / LTARV) | Target ARV / SqFt | Typical Build Timeline |
|---|---|---|---|---|
| Detached Guest Casita / ADU (600–1,000 SqFt · HB 2720) | $265–$340 / SqFt | 85% LTC / 75% LTARV | $475–$680 / SqFt | 5–7 Months (Permit + 4 Draws) |
| Scottsdale Contemporary Remodel + Addition (85254 / 85251) | $290–$395 / SqFt | 85% LTC / 70% LTARV | $550–$785 / SqFt | 6–9 Months |
| Arcadia / Biltmore Luxury Spec Rebuild (85018 / 85016) | $425–$575 / SqFt | 80% LTC / 65%–70% LTARV | $875–$1,250 / SqFt | 11–15 Months |
| Paradise Valley / Silverleaf Custom Estate ($5M–$15M+) | $550–$850 / SqFt | 75% LTC / 65% LTARV | $1,150–$1,850 / SqFt | 14–20 Months |
Scottsdale & Greater Phoenix Sub-Market Coverage (Stephen R. Mannenbach)
North Scottsdale (Pinnacle Peak, Troon & Grayhawk) ($1,485,000)Silverleaf & DC Ranch ($2,950,000)McCormick Ranch ($1,120,000)The "Magic 85254" & Kierland Corridor ($1,195,000)Old Town Scottsdale & South Scottsdale (85251 / 85257) ($785,000)Town of Paradise Valley (85253) ($4,250,000)Arcadia & Arcadia Lite (85018) ($1,650,000)Arizona Biltmore & Camelback Corridor (85016) ($960,000)Gainey Ranch ($1,550,000)Cave Creek & Carefree ($1,080,000)Fountain Hills ($845,000)Desert Ridge, High Street & Tatum Corridor ($875,000)
Stephen R. Mannenbach is a Licensed Real Estate Salesperson / REALTOR® in the State of Arizona (ADRE #SA713873000), brokered by HomeSmart LLC. Equal Housing Opportunity. All property square footage, HOA fees, school boundaries, business financials, and market statistics are deemed reliable but not guaranteed and should be independently verified through ARMLS and Maricopa County records.