Roof Trusses vs Rafters
Trusses are engineered, delivered as a complete set and stood in a day, and on a straightforward roof they beat stick framing on both material and labour. Rafters are cut on site, need a ridge and ceiling ties, and take a skilled crew longer — but they leave the attic open and they can be adjusted to a plan that trusses would have to be redesigned for. Most new roofs are trussed; most additions and complicated roofs are not.
Start here
- Roof Truss Count & Cost Calculator — truss count, bracing and delivered cost for a roof
- Rafter Length & Cut Calculator — rafter length, plumb cut angle and lumber cost
- 24x30 Garage Shell Material & Cost Calculator — slab, wall framing, trusses and sheathing for a garage shell
- Framing Lumber Cost Estimator — board feet, piece count and cost for a framing order
| Trusses | Rafters (stick framing) | |
|---|---|---|
| Material cost | Lower — smaller lumber, engineered web | Higher — larger members, ridge beam |
| Labour | A day to set with a crane on a typical house | Several days of skilled cutting and fitting |
| Clear span | 40 ft and beyond with no interior bearing | Limited; usually needs interior bearing walls |
| Attic space | Webs fill it; storage only, unless attic trusses | Open — can be finished or converted later |
| Lead time | 2–6 weeks, engineered and ordered | None — lumber off the rack |
| Design changes | A redesign and a new order | Cut differently the same day |
| Complex roof shapes | Possible but expensive in girder trusses | Where stick framing is genuinely better |
| Site access | Needs crane access and a place to stack | Carried up piece by piece |
| Best for | New builds, garages, simple gable and hip roofs | Additions, dormers, vaulted ceilings, tight sites |
Why trusses win on a simple roof
A truss uses 2x4 chords and webs to do what a rafter needs a 2x10 to do, because the geometry carries the load rather than the depth of the timber. Less lumber, engineered to the exact span, and delivered as numbered units that go up in order. On a rectangular house or a garage, the entire roof structure can be standing before lunch.
The clear span is the other advantage, and it is the one that changes floor plans. A trussed roof can span forty feet with no interior bearing wall, which means the walls below are free to go where the rooms want them. A stick-framed roof of the same width generally needs a bearing wall or a substantial ridge beam down the middle, and that wall has to be somewhere.
Why rafters still get built
The attic is the usual reason. A conventional truss fills the roof space with webs, and cutting one is prohibited — the engineering assumes every member is intact. Rafters leave the volume open for storage now or a finished room later, and a vaulted or cathedral ceiling is straightforward with rafters and a structural ridge.
Complicated roofs are the other reason. Dormers, valleys, changes of pitch and roofs that meet an existing structure at an odd angle are all things a carpenter can cut on site and a truss plant has to engineer as girder trusses, which are heavy, expensive and unforgiving of a wall that ended up half an inch out.
Then there is access. Trusses arrive on a long trailer and want a crane and somewhere to stack; a tight urban lot, a back garden, or a site at the end of a narrow track may simply not allow it. Rafter stock goes up a ladder.
Lead time is the hidden constraint
Trusses are ordered against a signed layout and take weeks to arrive, so the design has to be finished long before the walls go up. Any change after that — a moved wall, an extra dormer, a revised pitch — is a new engineering package and a new delivery date. On a project where the plan is still moving, that rigidity costs more than the material saving.
Stick framing has no lead time and absorbs late changes at the price of a few boards. On a small addition where the roof has to meet an existing house that was never quite square, that flexibility is worth real money.
Result
A new house or garage with a simple gable or hip roof, a firm plan and crane access: trusses, ordered early. An addition, a dormer, a vaulted ceiling, a roof that has to meet existing work, or a site a truck cannot reach: stick framing. If the attic will ever be a room, decide that now — attic trusses exist and cost more, and converting an ordinary trussed roof later is not a small job.
Common questions
- Are trusses cheaper than rafters?
- On a straightforward roof, yes — usually on material and clearly on labour. On a complicated roof needing girder trusses, or a small job where lead time matters, stick framing can be cheaper overall.
- Can I cut a truss to make attic space?
- No. Every member is part of the engineered load path, and cutting one voids the design. If you need the space, order attic trusses or frame the roof conventionally.
- Do trusses need interior bearing walls?
- Usually not — clear-spanning the whole width is the main structural advantage. Confirm against the truss drawings, since some long-span designs still require intermediate support.
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Updated 09/03/2026