Second Story Addition in Thornton, CO — Costs $85,987 to $537,417
What does second story addition cost in Thornton? Average $214,967, ranging $85,987–$537,417. Labor runs $32.99/hr locally — 7% above the national average. Free breakdown with material + labor split.
Thornton, CO Market
+7% vs nationalLabor Rate
$32.99/hr
Material Index
105
Avg Permit Cost
$1,487
Median Home Price
$419,586
Thornton is a mid-sized city in Colorado with a healthy pool of local contractors. Homeowners generally have several options to compare for a second story addition, which helps keep pricing competitive. Costs in Thornton run slightly above the national average, though the gap is modest enough that smart material choices and timing can close it. The median home in Thornton is valued at $419,586, putting this project at about 51.2% of home value — a moderate investment with a projected 60% ROI.
Low Estimate
$85,987
National: $80,000
Mid-Range
$214,967
National: $200,000
High End
$537,417
National: $500,000
Per Sq Ft
$322
National: $300
Second Story Addition Cost Calculator for Thornton
Adjusted for Thornton's labor rate ($32.99/hr) and material costs (index 105).
Mid-grade materials, good quality fixtures, standard options.
Estimated Total in Thornton
$214,967
Based on 200 sq ft at mid quality, adjusted for Thornton market rates.
Local Cost Breakdown
At Thornton's average rate of $32.99/hr (10% above national avg)
Material cost index 105 (5% above national baseline of 100)
Second Story Addition vs. Home Value in Thornton
| Metric | Thornton | National Avg |
|---|---|---|
| Second Story Addition (Mid-Range) | $214,967 | $200,000 |
| Median Home Price | $419,586 | $350,000 |
| Project as % of Home Value | 51.2% | 57.1% |
| Estimated ROI | 60% | 60% |
| Median Household Income | $63,487 | $75,000 |
What Affects the Price in Thornton
- 1Local labor rates ($32.99/hr in Thornton)
- 2Material cost index (105 vs national 100)
- 3Total square footage added
- 4Structural reinforcement of first floor
- 5Staircase addition
- 6Roof removal and replacement
Popular Upgrades
- Master suite
- Additional bedrooms
- Jack-and-Jill bathroom
Other Projects in Thornton, CO
Accessory Dwelling Unit (ADU) Construction
$161,225
Room Addition
$96,735
Swimming Pool Installation
$69,541
Garage Addition
$59,116
Home Addition
$85,788
Inground Swimming Pool
$69,380
Attic Conversion
$59,252
Swimming Pool Construction
$53,866
Second Story Addition in Other Colorado Cities
Planning a Second Story Addition in Thornton
Building permits are typically required for a second story addition in Thornton. The average permit fee in this area is $1,487, though costs vary based on project scope. Permit fees in this market are above average — factor them into your total budget. Plan for 4-8 months from start to finish.
A second story addition is a complex project best left to licensed professionals. In Thornton, skilled contractors charge an average of $32.99/hr, and the specialized nature of this work means cutting corners on labor can lead to costly rework.
For the median Thornton household earning $63,487/year, this project at $214,967 represents a significant investment. Consider financing options or phasing the work to spread costs over time.
Second Story Addition — National Guide
See the full national cost guide with DIY tips, cost factors, and ROI analysis.
All Construction Costs in Thornton
View labor rates, material costs, and project estimates for Thornton, CO.
Explore All Project Cost Guides
Compare costs across 120+ home improvement projects in 3,636 cities nationwide.
View All Project Costs