How many trusses do I need?
Trusses = (building length in inches / spacing) + 1
A 30 ft long garage at 24 in on center needs 30 x 12 / 24 + 1 = 16 trusses, including the two gable ends. At 16 in on center it needs 23.
2026 truss prices
| Truss type | Price per ft of span | 24 ft span, each |
|---|---|---|
| Common (Fink, W) | $5 to $9 | $120 to $216 |
| Mono | $4 to $8 | $96 to $192 |
| Scissor | $7 to $12 | $168 to $288 |
| Attic room | $14 to $25 | $336 to $600 |
Prices swing with lumber markets and region. Spans over 40 ft, heavy snow loads and girder trusses cost more.
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Trusses vs stick-framed rafters
- Trusses: engineered, fast to set, span long distances without interior bearing walls. Little usable attic.
- Rafters: more labor, but allow vaulted ceilings and open attics. Price them with the rafter calculator.
Before you order
- Confirm the snow load and wind speed for your county. The truss plant designs for them.
- Order 1 or 2 extra common trusses for gable overhang framing if needed.
- Plan how they get lifted. A crane is cheaper than a broken truss.
Sources and further reading
- 2021 International Residential Code, Chapter 8: Roof-Ceiling Construction
- American Wood Council: span tables and framing guides
- OSHA: Fall protection for roof work
Frequently asked questions
How far apart are roof trusses?
24 inches on center is standard for trusses. 16 inches is used for heavy snow loads, tile roofs or thin sheathing.
How much does a roof truss cost?
A common 24 ft truss runs about $120 to $220 in 2026. Scissor and attic trusses cost more.
Can I build my own trusses?
Many areas require engineered, stamped trusses for permits. Site-built trusses for small sheds may be allowed with an approved design.
What pitch are standard trusses?
4/12 to 6/12 is most common, but plants can build almost any pitch.