Home addition cost in Boise, ID
Local estimate from BLS wage data and BEA price levels. Reviewed Nov 4, 2026.
- Typical range (300 sq ft)
- $34,700 – $70,400
- Per sq ft
- $114 – $228
- before permit
- Versus US midpoint
- −9%
- US $57,500
- Rank of 300 metros
- #177
- 1 = most expensive
Local price for a home addition in the Boise area: $34,700 to $70,400 for 300 sq ft. The low end is a basic job on easy ground; the high end is a premium spec with harder access. The midpoint runs 9% lower than the US figure. Carpenters earn a median of $24.45 an hour in the Boise area, 16% below the US median of $29.12.
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Estimated cost for 300 sq ft in Boise, ID, standard level
$45,400 to $59,700
About $148 to $194 per sq ft before permits. Labor is about 65% of the bill.
| Part | Low | High |
|---|---|---|
| Materials | $15,000 | $19,600 |
| Labor | $29,500 | $38,500 |
| Permits and fees | $930 | $1,550 |
| Total | $45,400 | $59,700 |
Cost breakdown for 300 sq ft in Boise, ID
| Part of the job | Low | Midpoint | High | Share |
|---|---|---|---|---|
| Materials | $11,500 | $17,300 | $23,100 | 33% |
| Labor | $22,700 | $34,000 | $45,300 | 65% |
| Permits and fees | $490 | $1,250 | $1,950 | 2% |
| Total | $34,700 | $52,500 | $70,400 | 100% |
Where the Boise price comes from
The wage side of the estimate leans on carpenters, who do 50% of the hours on a typical job. Their local median is $24.45 an hour. Add the other trades involved and the blended wage index for Boise is 0.89 (US = 1.00), which puts labor at 65% of the total.
Materials are scaled with BEA's regional price parity for goods. Boise is at 96.2 against 100 for the US, so a materials line of $18,000 nationally becomes $17,300 here (midpoint, 300 sq ft). Permits follow the all-items index of 98.4: $490 to $1,950.
Who does the work: Boise trade wages
The labor line is built from BLS wage data, one trade at a time. This job draws on 6 trades. We compare each trade's local median with the US median, weight the ratios by how much of the job each trade does, and apply the blend to the national labor cost. For Boise the blend is 0.89.
Carpenters (47-2031), 50% of the weighting: a median of $24.45 an hour, 16% below the US median of $29.12. The middle half of them earn between $21.63 and $30.30 an hour. About 4,080 work in the metro. That is 104.1 per 10,000 jobs, compared with 43.1 nationally, which suggests plenty of local crews to bid.
Cement masons and concrete finishers (47-2051), 10% of the weighting: a median of $26.95 an hour, in line with the US median of $27.41. The middle half of them earn between $23.13 and $29.50 an hour. About 1,110 work in the metro. That is 28.3 per 10,000 jobs, compared with 13.3 nationally, which suggests plenty of local crews to bid.
For electricians (47-2111, weighted 10%) the local median is $29.62 an hour, which is in line with the national $30.38. The middle half of them earn between $23.58 and $39.44 an hour. BLS counts 2,510 of them working in the area, 64.1 for every 10,000 jobs (US: 48.7), so the local bench is deeper than average.
Plumbers, pipefitters and steamfitters (47-2152), 10% of the weighting: a median of $27.38 an hour, 11% below the US median of $30.67. The middle half of them earn between $22.40 and $35.89 an hour. About 1,760 work in the metro. That is 44.9 per 10,000 jobs, compared with 30.0 nationally, which suggests plenty of local crews to bid.
For drywall and ceiling tile installers (47-2081, weighted 10%) the local median is $21.30 an hour, which is 25% below the national $28.33. The middle half of them earn between $18.05 and $28.35 an hour. BLS counts 480 of them working in the area, 12.3 for every 10,000 jobs (US: 5.3), so the local bench is deeper than average.
Roofers (47-2181), 10% of the weighting: a median of $28.89 an hour, 8% above the US median of $26.65. The middle half of them earn between $22.15 and $31.00 an hour. About 650 work in the metro. That is 16.6 per 10,000 jobs, compared with 8.7 nationally, which suggests plenty of local crews to bid.
A quick sensitivity check: moving the lead trade (carpenters) from the median to the 75th percentile wage adds about $3,850 to the midpoint estimate; the 25th percentile takes off about $1,850. That is a swing of roughly 3.5% to 7.3% of the total, which is useful for judging whether a bid reflects wages or something else, such as scope or margin.
Boise City has 391,790 jobs in total (BLS, May 2025), ranking 67th by size among the 300 metros on this site.
| Trade | Weight | 25th pct | Median | 75th pct | US median | Ratio | Level used |
|---|---|---|---|---|---|---|---|
| Carpenters (47-2031) | 50% | $21.63 | $24.45 | $30.30 | $29.12 | 0.84 | metro |
| Cement masons and concrete finishers (47-2051) | 10% | $23.13 | $26.95 | $29.50 | $27.41 | 0.98 | metro |
| Electricians (47-2111) | 10% | $23.58 | $29.62 | $39.44 | $30.38 | 0.97 | metro |
| Plumbers, pipefitters and steamfitters (47-2152) | 10% | $22.40 | $27.38 | $35.89 | $30.67 | 0.89 | metro |
| Drywall and ceiling tile installers (47-2081) | 10% | $18.05 | $21.30 | $28.35 | $28.33 | 0.75 | metro |
| Roofers (47-2181) | 10% | $22.15 | $28.89 | $31.00 | $26.65 | 1.08 | metro |
| Blended | 100% | 0.89 | |||||
The best months for home addition in Boise
Climate numbers on this page come from NOAA's 1991-2020 U.S. Climate Normals at the nearest suitable station, Boise Air Terminal (5 miles from the city center). They are 30-year averages, so any one year can run hotter, colder or wetter.
For digging, grading and setting material in the ground, the comfortable months in Boise are March through June and September through October: 6 of 12. Outside them, January, February, November and December have an average overnight low at or below freezing (32°F), and July and August have an average daytime high of 90°F or more.
In January, February, November and December the average low is at or below freezing, which means frozen ground and slower digging, compaction and sod or stone placement. NOAA counts about 108 days a year with a low at or below 32°F at this station.
Boise gets about 12 inches of precipitation in a normal year, including roughly 18 inches of snow. The wettest months are January, May and December (1.5 inches in December). Inside the workable window, June and September are the driest, at 0.8 and 0.4 inches. The station averages about 55 days a year at 90°F or above.
We do not adjust the estimate by month, because we have no reliable published data on seasonal pricing. It is still worth asking contractors whether an off-peak start date changes their bid.
| Month | Avg high °F | Avg low °F | Precip (in) | For this job |
|---|---|---|---|---|
| Jan | 39 | 26 | 1.4 | Cold |
| Feb | 46 | 29 | 1.0 | Cold |
| Mar | 56 | 35 | 1.3 | Workable |
| Apr | 62 | 40 | 1.2 | Workable |
| May | 72 | 48 | 1.4 | Workable |
| Jun | 81 | 54 | 0.8 | Workable |
| Jul | 93 | 62 | 0.2 | Hot |
| Aug | 91 | 61 | 0.2 | Hot |
| Sep | 80 | 53 | 0.4 | Workable |
| Oct | 65 | 42 | 0.8 | Workable |
| Nov | 49 | 32 | 1.2 | Cold |
| Dec | 39 | 25 | 1.5 | Cold |
Cost by quality level and size in Boise
The cited range is split into basic, standard and premium bands, then scaled to Boise. Bands overlap, because plenty of standard jobs cost as much as a light premium one. Sizes run from bump-out (100 sq ft) to large suite (600 sq ft).
Basic
$34,700 to $49,000
Bump-out or simple room without plumbing
Standard
$45,400 to $59,700
Standard room addition with HVAC and electrical
Premium
$56,100 to $70,400
Large addition with bath or kitchen and a new foundation
| Size | Basic | Standard | Premium |
|---|---|---|---|
| bump-out (100 sq ft) | $11,900 – $17,000 | $15,800 – $20,900 | $19,600 – $24,800 |
| 20x20 room (400 sq ft) | $46,100 – $64,900 | $60,200 – $79,000 | $74,300 – $93,200 |
| large suite (600 sq ft) | $68,900 – $96,800 | $89,800 – $118,000 | $111,000 – $139,000 |
Planning more than one job in Boise?
Jobs that often go together with home addition are priced below at their usual sizes, using the same Boise wage and price inputs. Compared with national midpoints, roof replacement comes out highest (+3%) and bathroom remodel lowest (−8%); the gap comes from the trades each job uses.
| Project | Size | Range | vs. US |
|---|---|---|---|
| Kitchen remodel | 120 sq ft | $17,500 – $29,800 | −6% |
| Bathroom remodel | 45 sq ft | $4,300 – $21,400 | −8% |
| Detached garage | 576 sq ft | $27,400 – $55,100 | −5% |
| Roof replacement | 2,000 sq ft of roof | $6,350 – $12,800 | +3% |
Boise against nearby metros and the rest of Idaho
Contractors rarely work more than an hour or two from home, so the neighboring metros set a rough ceiling and floor for your quotes. Midpoints for 300 sq ft range from $51,100 to $64,000 across Boise and its five closest metros.
| Area | Range | Midpoint | vs. here |
|---|---|---|---|
| Boise, IDthis page | $34,700 – $70,400 | $52,500 | |
| Idaho Falls, ID190 miles | $34,500 – $69,900 | $52,200 | −1% |
| Logan, UT235 miles | $33,700 – $68,400 | $51,100 | −3% |
| Salt Lake City, UT235 miles | $37,100 – $75,300 | $56,200 | +7% |
| Bend, OR250 miles | $42,300 – $85,600 | $64,000 | +22% |
| Ogden, UT255 miles | $34,400 – $69,800 | $52,100 | −1% |
| Idaho (statewide) | $34,700 – $70,300 | $52,500 | level |
| United States | $38,000 – $77,000 | $57,500 | +9% |
Out of the 300 metros we cover, Boise ranks #177 for the cost of this job (#1 is the most expensive). Statewide, Boise is 0% above the Idaho figure.
Elsewhere in Idaho
| Metro | Size | Range | Midpoint | vs. here |
|---|---|---|---|---|
| Idaho Falls, ID | 81,840 jobs | $34,500 – $69,900 | $52,200 | −1% |
| Coeur d'Alene, ID | 72,280 jobs | $35,700 – $72,300 | $54,000 | +3% |
Metros of a similar size
Big cities and small ones price differently, so here is Boise against the 4 metros with the closest total employment.
| Metro | Size | Range | Midpoint | vs. here |
|---|---|---|---|---|
| Charleston, SC | 394,170 jobs | $33,600 – $68,200 | $50,900 | −3% |
| Tucson, AZ | 389,630 jobs | $33,800 – $68,600 | $51,200 | −3% |
| Columbia, SC | 394,200 jobs | $32,900 – $66,800 | $49,900 | −5% |
| Allentown, PA | 377,180 jobs | $38,500 – $78,100 | $58,300 | +11% |
Home addition: what moves the price in Boise
Permits
Construction permits run $500-$2,000, or $5-$21 per $1,000 of project cost (HomeGuide).
Foundation
A foundation, framing, roofing and matching exterior finishes all have to be built before the interior work starts.
Type of addition
A new room is $125-$250 per sq ft; a bump-out $85-$200; an attic conversion $50-$150; a garage conversion $50-$200 (HomeGuide).
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Home addition in Boise: your questions
+How much does it cost to build a home addition in Boise?
For 300 sq ft, expect $34,700 to $70,400 in the Boise area. A standard-spec job lands at $45,400 to $59,700. Small jobs usually cost more per sq ft and large ones less.
+What is the price per sq ft for home addition in Boise?
About $114 to $228 per sq ft for materials and labor, plus $490 to $1,950 for the permit if one is needed. The US range is $125 to $250.
+Is home addition cheaper in Boise or Idaho Falls?
Idaho Falls is 190 miles away. The midpoint for 300 sq ft there is $52,200, which is 1% less than Boise ($52,500). Wage and materials indexes both feed that gap.
+How much of the bill is labor in Boise?
About 65% at the midpoint, or $34,000 out of $52,500. Materials are 33% and permits 2%. Nationally, labor is 67%.
+What would 20x20 room (400 sq ft) cost in Boise?
$46,100 to $93,200. Pick a different size in the estimator above to get your own number.
+Does home addition need a permit in Boise?
Often, but rules are set by your city or county building office, so call before you hire. Budget $490 to $1,950 for fees in the Boise area (our national range of $500 to $2,000 scaled by the local price level).
+Is Boise expensive for home addition compared with the rest of Idaho?
Boise is 0% above the Idaho statewide estimate ($52,500 at the midpoint). We cover 3 metros in Idaho; see the state page to compare them.
+What do carpenters earn in Boise?
The BLS median is $24.45 an hour in the Boise area, compared with $29.12 nationally. The 25th to 75th percentile range is $21.63 to $30.30.
+What do basic and premium home addition work cost in Boise?
For 300 sq ft, basic work runs $34,700 to $49,000 and premium work $56,100 to $70,400. Basic means: bump-out or simple room without plumbing. Premium means: large addition with bath or kitchen and a new foundation.
+When is the best time to build a home addition in Boise?
Based on NOAA 1991-2020 normals, the comfortable months for this kind of work are March through June and September through October. June and September are typically the driest of those months. Local contractors' schedules matter as much as the weather, so book early for the busy months.
Home addition near Boise
Where these numbers come from
Base prices are national ranges from the sources below. We scale labor by local BLS wages, materials by BEA goods prices and permits by the BEA all-items price level. Full method on the methodology page.
- HomeGuide: How Much Does a Home Addition Cost? (2026) (accessed November 4, 2026)
- Cost to Renovate: Renovation Labor Report 2026: Where the Money Goes (accessed November 4, 2026)
- HomeGuide: 2026 Building Permit Costs | Fees & Cost Calculator (accessed November 4, 2026)
- BLS Occupational Employment and Wage Statistics, May 2025
- BEA Regional Price Parities, 2024
- NOAA NCEI U.S. Climate Normals, 1991-2020
Note on derived figures: Materials = 32% of the installed price, from Cost to Renovate's mid-range 'Structural' category split (56% labor, 32% materials, 11% permits and design). It is a category average rather than an addition-specific figure.