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30×40 Detached Garage Cost in Montana (2026)

A 30×40 detached garage in Montana costs about $54,762 turnkey in 2026 ($45.64 per sq. ft.). Here's the itemized breakdown of materials, site prep and labor, using local crew rates.

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Materials Package
$21,617
Studs, trusses, sheathing, shingles, siding & doors
= Rows 3–7 below, materials only
Slab & Site Prep
$10,327
Grading, thickened-edge footing & concrete floor
= Rows 1–2 below, installed price
Turnkey Installed Total
$54,762
$45.64 per sq. ft.
Complete garage built by a local licensed crew
= All rows below, installed price
A fair bid from a local builder in Montana should land between $50,381 and $60,238. Get 3 quotes, and if one is far outside this range, ask why.

Estimate only. Actual prices vary. No guarantee or warranty. Use as a guide only. Read the full disclaimer

Itemized cost breakdown

#ItemQuantityMaterialsLaborInstalled
1Site grading & padClear, level & compact the building pad1,496 sq ft$593$889$1,778
24" slab with thickened-edge footing3,000 PSI concrete, rebar, vapor barrier, forms21.4 cu yd$4,213$2,911$8,549
32×6 wall framing & sheathing129 studs, treated plates, headers, 7/16" OSB129 studs + 48 sheets$2,441$4,528$8,363
4Roof trusses & roof sheathing21 trusses at 24" on center, 6/12 pitch, OSB decking21 trusses + 47 sheets$4,756$2,264$8,424
5Architectural shingles & lap siding30-yr shingles, synthetic underlayment, engineered-wood lap siding & trim15.0 squares + 1,513 sq ft$7,106$4,959$14,478
6Garage & entry doorsDetails in the spec sheet🔒 Included in $19 spec sheet$6,174$1,294$8,962
7Basic electricalDetails in the spec sheet🔒 Included in $19 spec sheet$1,140$970$2,532
8Permit, nails/hardware & dumpsterDetails in the spec sheet🔒 Included in $19 spec sheet$1,397$0$1,676
Turnkey total$27,820$17,815$54,762
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Prices use 2026 material costs and typical local crew rates. Site work, custom options and material price swings can move your final price.

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Builder Spec Sheet & Shopping List

The same line items as this page in an editable Excel file and a PDF, each with a short spec, quantity, materials, labor and installed price. Plus a permit and site-prep checklist and a sheet for comparing 3 builder bids. 30-day money-back guarantee.

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Common questions

How much does a 30×40 Detached Garage cost in Montana?

About $54,762 fully built by a local crew in 2026, or roughly $21,617 for the materials kit alone. Most fair bids land between $50,381 and $60,238.

What drives the price up or down?

Site prep (slope, soil, driveway access), floor choice, doors and insulation, and local labor rates. Lumber and steel prices also move a few percent a year.

Do I need a permit?

Most counties require a building permit for structures over 200 sq ft. Call your county building department with your size and location before you order materials.

How do I make sure I'm getting a fair quote?

Get at least 3 itemized bids for the same spec. Compare them line by line against this breakdown and ask about anything far above or below it.

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