Roof Truss vs Stick Framing: Spans, Cost, and Engineering
The Fundamental Difference
Stick framing uses conventional lumber: a ridge board at the peak, rafters extending from the ridge to the wall plates, and ceiling joists connecting the two walls. Load paths are straightforward. Truss construction uses engineered prefabricated triangles. Load is distributed through internal web members instead of concentrated on perimeter supports.
The choice determines labor cost, material cost, span capability, attic usability, and design flexibility. Most new residential construction uses trusses. Renovation and high-end work often use stick framing. Understanding the trade-offs prevents costly mistakes.
Stick Framing Basics
Stick framing consists of three components: the rafter (extends from ridge to plate, carries roof load), the ceiling joist (spans between walls at the plate, prevents rafter thrust and provides attic floor), and the ridge board (ties the two rafters together at the peak).
How it works: Each rafter leans inward toward the opposite wall, like an inverted V. The ceiling joist connects the two lower ends of the rafters, tying them together so they can’t spread apart. Without the ceiling joist, the roof would push the walls outward.
Loads on rafters are high: Each rafter spans from the ridge to the wall plate (the full run of the roof), carrying not only the roof dead load but also the component of ceiling joist tension. A 28-foot-wide house with a 6:12 pitch (common in snow regions) has rafters spanning approximately 17 feet. A 2×10 rafter in Douglas Fir-Larch, No. 2 grade, at 16 inches on center, can span about 16-17 feet with a 40 psf roof load and 10 psf ceiling load. Any increase in load (snow region, heavy tile roof) or span exceeds the capacity of standard lumber, requiring upsizing or engineered design.
Truss Advantages
Spans: Trusses span farther than rafters of equivalent depth. A 2×4 truss web can span 32-40 feet, while a 2×10 rafter spans only 16-18 feet. This is because truss geometry is optimized — the triangular shape and internal web members distribute loads more efficiently than a simple rafter.
Speed: Prefabricated trusses are installed quickly. An entire roof can be placed in one day; stick framing takes 3-5 days of careful assembly. This speed reduces labor cost.
Simplicity: No complex cuts or on-site engineering. Workers place trusses on the wall plates, brace them, and sheathe. Mistakes are rare.
Uniform ceiling: Trusses have a flat lower chord (the ceiling line). The attic space above is triangular but unobstructed. Stick framing often requires collar ties and diagonal bracing, cluttering the attic.
Material consistency: Factory-made trusses use consistent lumber and are stress-tested in the plant. Field-built stick frames depend on carpenter skill and available materials.
Truss Disadvantages
Cost: High initial material cost (trusses cost 30-50% more than stick framing material). However, labor savings often offset this. The net cost is usually 10-20% higher for trusses, but this varies by region and builder.
Attic usability: Standard trusses leave minimal usable attic space. The lower chord (ceiling line) is at the plate level, and the triangular void above has low clearance near the edges. Finished attic space (a bonus room) requires expensive attic trusses with raised lower chords, adding significant cost.
Inflexibility: Trusses are designed for a specific roof pitch, span, and load. Changing the slope, adding a skylight, or modifying framing is difficult. The truss must be redesigned and replaced.
Large openings: A ductwork penetration or large skylight in a truss requires structural analysis and reinforcement. In stick framing, headers are added locally with minimal disruption.
Stick Framing Advantages
Flexibility: Rafters are individual members. Skylights, dormers, and openings are framed in as needed. The ridge board and ceiling joist can be interrupted for attic access without redesign.
Attic space: Full attic height is available. Collar ties (horizontal members near the peak) provide lateral bracing and tie rafter pairs together. Collar ties are sized for light loads and don’t significantly reduce headroom.
Remodeling: Removing an interior wall and extending the rafter span requires new rafters and ceiling joists, but the design is straightforward. With trusses, the entire roof system must be redesigned.
Aesthetics: Exposed stick framing (visible rafters, ridge beams in great rooms) is architecturally appealing. Truss members are often hidden by ceiling, losing the appeal.
Stick Framing Disadvantages
Spans: Limited to moderate spans (16-20 feet for standard lumber in snow regions). Longer spans require larger lumber or engineered design, raising cost.
Labor: Requires skilled carpenters. Each rafter must be cut to length, the ridge beam cut and installed, then rafters attached. Four days minimum on a simple roof.
Ceiling joists: Often required, adding material cost and complicating attic layout. They must cross the entire width, limiting flexibility for future renovation.
Engineering: Non-standard spans or loads require engineered design. The engineer sizes rafters, collar ties, and ceiling joists. This adds design cost and schedule delay.
Load Comparison: Snowload Example
A 30-foot-wide house in a heavy snow region (60 psf roof load) illustrates the differences.
Roof dead load is typically 15 psf (roof deck, shingles, insulation). Snow load is 60 psf. Ceiling load is 10 psf. Total design load: 85 psf.
Stick framing option: A 2×12 rafter at 16 inches on center, spanning approximately 16 feet (from ridge to plate), can carry about 65-70 psf. This is insufficient. The rafter must be upgraded to 2×14 (span capability increases to roughly 85 psf) or spaced at 12 inches on center. Either option increases material cost.
Truss option: A factory-designed truss for 30-foot span, 85 psf load, and the specified pitch is delivered ready to install. The truss depth might be 12-14 inches (vs. a 2×14 rafter at 11.25 inches, but the truss’s triangular interior distribution makes it stiffer and stronger). Cost difference: the truss costs $300-400 per unit (maybe 8-10 trusses per roof), so $3,000-4,000 material cost. Stick framing might cost $2,000-2,500 in lumber but requires 2-3 additional labor days at $50-75/hour. Net cost is similar; the truss wins on schedule.
When to Specify Each Method
Use trusses for:
- Simple rectangular buildings with standard roof pitch (4:12 to 8:12)
- Spans exceeding 20 feet
- Projects where labor cost is high relative to material cost
- Heavy snow loads or unusual loads (trusses are engineered for the condition)
- New construction where speed matters
- Buildings with open floor plans (no interior load-bearing walls to support rafter loads)
Use stick framing for:
- Complex roof geometry (multiple pitches, valleys, dormers)
- Homes with planned attic finishing (a bonus room or master suite)
- Historical renovations where truss aesthetics don’t match
- Smaller spans (under 20 feet) where standard lumber is adequate
- Projects with experienced carpenters and lower labor rates
- Buildings where interior walls can bear rafter loads, reducing span
- Situations requiring frequent modification or future reconfiguration
Design and Engineering Requirements
Stick framing: The builder or architect establishes the span, pitch, and load. Local span tables determine member size (IRC Table R802.5.1). If the span exceeds the tables, an engineer designs the rafters, ceiling joists, and lateral bracing.
Trusses: The building designer specifies the span, pitch, overhang, and loads (snow, wind, dead load). The truss manufacturer’s engineer designs the truss (depth, web configuration, member sizes) and produces shop drawings. The general contractor verifies the design matches the architect’s intent and confirms bearing and bracing details.
Both methods require verification that the roof system can be properly supported. Bearing points must be at walls or beams. Lateral bracing must prevent trusses or rafters from rolling over during construction.
Common Errors
Underestimating snow load. Snow load varies by elevation and latitude. Using national averages instead of local values undersizes the roof. Ask the building official for the specific snow load for the site.
Oversizing stick framing unnecessarily. Many builders install 2×12 rafters everywhere out of habit, even where 2×10 would suffice. Upsizing adds cost without benefit.
Forgetting ceiling joists in stick framing. Without ceiling joists, rafter thrust pushes the walls outward. Verify ceiling joists are sized for tension and connect both walls.
Inadequate bracing during truss installation. Trusses are unstable until fully sheathed and braced. Workers installing trusses must use temporary diagonal bracing to prevent tipping.
Cutting truss webs for mechanical systems. Cutting into truss members (to run ductwork or pipe) requires engineering. The truss load path is disrupted, and the connection detail must be reinforced.
Cost Analysis Template
For a 30×40 house, 7:12 roof pitch, 40 psf snow load (moderate climate):
Stick framing:
- Lumber: 2×10 and 2×12 rafters, 2×8 ceiling joists, ridge board: $2,500
- Labor: 4 days, 2 carpenters: 64 hours × $50/hr = $3,200
- Total: $5,700
Truss option:
- Trusses (20 units × $350): $7,000
- Labor: 1.5 days, 2 workers, 24 hours × $50/hr = $1,200
- Total: $8,200
The truss option costs 44% more in material but 62% less in labor. If labor rates are $75/hour, labor cost becomes $1,800, and the net difference narrows to 26%.
Choosing the right framing method saves thousands over the project and determines long-term satisfaction with the building.