Roof and floor trusses have replaced most stick-built roof framing in residential construction. A truss is a prefabricated frame of lumber members connected by steel plates, engineered as a single unit and set in place with a crane. Because the whole triangle works together, trusses span farther with less material than rafters and joists framed one piece at a time. Lumber operations keep investing in this product line. Hancock Lumber of Casco, Maine, acquired Mainely Trusses of Fairfield in 2018, becoming the first retailer in the state to own and operate its own roof and floor truss manufacturing facility. The company had cut logs since 1848 and already ran three eastern white pine sawmills and a wall panel plant, so the truss plant added a natural product line. The same expansion pattern shows up across building products: manufacturers keep adding capacity through acquisitions, and mineral wool insulation gains ground as producers push into non-combustible materials. For builders, knowing how trusses are manufactured and selected turns a commodity order into a controlled part of the schedule.
Timber Roof Trusses: Anatomy and Common Configurations
Every truss follows the same geometry: two top chords meet at the peak, a bottom chord ties the ends together, and web members connect the chords to form triangles. Triangles are stable shapes, so the frame resists bending by converting it into compression and tension in individual members. Steel connector plates, pressed into both faces at each joint, transfer the forces between members. The timber roof trusses used in most houses share this design, whether they span a 24-foot living room or a 50-foot barn.
How a roof truss carries load
Load travels down through the assembly in a defined path. Roofing and sheathing press on the top chords. The webs pass that force down to the bottom chord, which works in tension and carries the load to the bearing points at the wall tops. Designers add up dead loads of about 10 to 15 pounds per square foot for roofing and sheathing, plus live loads that vary by region: snow loads of 20 to 40 psf cover most of the northern United States, and wind uplift pulls upward on the same members. Truss design software checks every member and plate against those loads before a single board is cut.
Plate-connected joints
The gang-nail plates that join the members are galvanized steel sheets with teeth pressed into the wood. A hydraulic press sinks the teeth on both faces at once, and the plate transfers tension and compression across the joint. Plate size and tooth pattern come from the engineering drawing, not from habit.
Common configurations
Roof trusses come in a handful of standard shapes. The Fink, or W, truss is the most common residential profile, with webs forming a W inside the triangle, and it handles spans of roughly 20 to 40 feet. The Howe truss adds vertical webs for longer spans and heavier loads. Scissor trusses create a vaulted ceiling by sloping the bottom chord. Parallel-chord trusses, with the top and bottom chords level, work for flat roofs and for floor systems.
How a Truss Plant Manufactures Roof and Floor Systems
A truss plant is part sawmill, part assembly line. It receives graded lumber, cuts every member to a computer-generated cutting list, and presses the joints in precise jigs. The result is a frame that arrives on site ready to set, with the engineering already stamped.
From design drawing to finished truss
Production follows six steps at most plants:
- An engineer designs the truss in truss design software from the architect’s roof plan.
- Lumber is selected by grade, usually spruce-pine-fir or southern yellow pine, and checked for moisture content.
- Automated saws cut each chord and web to length with the correct end angles.
- Crews lay the cut members into a steel jig table that locks the geometry in place.
- A hydraulic press drives the connector plates into both faces at every joint.
- Inspectors check dimensions, plate placement, and camber, then bundle the trusses for delivery.
Floor trusses and open webs
Floor trusses use the same manufacturing process with parallel chords and open webs. The open web is their advantage: ducts, pipes, and wires run through the openings instead of under the floor, which saves ceiling height in basements and between stories. Open-web floor trusses span 30 to 40 feet at 24 inches on center, where solid 2×10 joists top out around 16 to 18 feet at the same spacing.
Acquisitions keep reshaping the sector
Truss plants change hands regularly as lumber and building products firms consolidate. Ceiling manufacturers follow the same playbook; one ceiling systems maker expanded its ceilings division through acquisition instead of building plants from scratch. For a lumber retailer, buying a working plant brings engineering staff, production crews, and delivery routes in one transaction.
Engineered Trusses vs Traditional Stick Framing
Builders choose between factory trusses and stick framing on every job. The trade-offs show up in span, waste, and labor hours on site. Roof trusses cost less to install because a crane sets a whole plane in hours, while rafters, ridge boards, and ceiling joists are cut and nailed one at a time.
Cost and material comparison
The table below compares the two approaches for a typical single-family roof and floor package:
| Criterion | Roof trusses | Floor trusses | Stick framing |
|---|---|---|---|
| Typical span | 20–40 ft | 30–40 ft | 16–28 ft |
| Spacing | 24 in on center | 24 in on center | 16 or 24 in on center |
| On-site labor | Low; crane setting | Low; crane setting | High; cut and nail each piece |
| Material waste | 2–5% | 2–5% | 10–15% |
| Engineering | Stamped at plant | Stamped at plant | Field-built, code-checked |
| Typical installed cost | $2.50–$4.00/sq ft | $4.00–$6.00/sq ft | Higher labor share |
Where stick framing still wins
Small roofs with hips, valleys, and dormers can cost more as trusses because each one becomes a custom design. Builders framing a simple gable on a small addition may find rafters faster than waiting on a truss order. Stick framing also allows last-minute changes on site.
When steel trusses are the better choice
Timber trusses stop being economical at very long spans and high loads. The design principles of steel trusses apply to warehouses, arenas, and commercial roofs where clear spans of 60 feet or more rule out wood members. Steel also answers non-combustible requirements and heavy point loads from equipment. A structural engineer sizes those frames, and steel fabrication happens off site just like wood truss production.
Selecting the Right Roof Truss System
Selection starts with the roof plan and ends with a stamped design. The choices that matter are span, loading, spacing, ceiling profile, and how the attic will be used. Builders who work through roof truss selection methodically send the truss designer a complete picture instead of a partial one.
Span, load, and spacing decisions
Trusses space at 24 inches on center in most houses, which matches 4×8 sheathing and cuts the number of members nearly in half compared with 16-inch joist spacing. Longer spans push member sizes up and may require 19.2-inch or 16-inch spacing. Snow loads in mountain states and wind zones in coastal areas change plate counts and lumber grades, so the local building code, not the catalog, sets the design loads.
Ceiling profiles and attic space
Standard trusses leave a low attic with little storage. Scissor trusses slope the ceiling for vaulted rooms. Room-in-attic trusses frame a full living space with interior walls and floor. Raised-heel trusses lift the top chord at the bearing point so full-depth insulation covers the exterior wall, closing the gap that flat-bottom trusses leave at the eaves.
Raised-heel and energy details
A standard 2×4 heel leaves 1 to 2 inches of insulation at the wall top. A raised heel of 6 to 12 inches lets the builder run full attic insulation to the outside edge, cutting heat loss along the eaves and avoiding ventilation chutes in many designs.
Vertical Integration: Why Lumber Operations Add Truss Manufacturing
The Hancock-Mainely deal is one example of a lumber company buying its way into engineered framing. Vertical integration gives the retailer control over production, margin, and delivery that a wholesale purchase order never offers. Hancock already manufactured lumber and wall panels, so adding engineered truss systems rounded out the product line for customers in Maine and New Hampshire.
What ownership changes for a retailer
Running a truss plant means carrying engineering liability, maintaining presses and saws, and staffing a fleet of truss trailers. In return, the retailer sets its own lead times and keeps the margin between raw lumber and the finished frame. The former owner usually stays on to run operations, which preserves customer relationships.
What builders gain
Builders buy framing and lumber from one supplier, coordinate engineering with the sales desk, and get trusses delivered on their schedule. For home builders, the same logic that connects land acquisition to the business plan applies to framing: secure the supply chain before committing to the construction schedule.
What to Check Before Ordering Trusses
A truss order moves faster when the builder comes prepared. The plant needs the roof plan, wall layout, and code requirements before engineering starts. Three documents come back and deserve review before production: the truss design drawings, the layout diagram, and the delivery and erection plan.
Documents to request
- Truss design drawings stamped by the engineer, listing every member size and plate.
- A layout diagram showing where each truss sits and how it bears on the walls.
- Lifting and bracing instructions from the manufacturer.
- The camber specification for long floor trusses.
Site and erection planning
Trusses arrive in bundles and must be stored flat and dry until setting day. A crane or telehandler sets them in sequence, and crews install temporary bracing before releasing the crane. Permanent bracing goes in with the sheathing and ceiling. The schedule should reserve the crane, the crew, and the delivery slot together, because a truss delivery that arrives a day early sits on the ground, and one that arrives late stops the roof.
Framing economics decide how much of a project’s profit survives construction. Just as land acquisition sets profit potential in home building, the framing system sets the pace and the waste rate that protect that potential. Trusses trade a longer planning window for faster, cleaner erection, and builders who plan the order the way they plan the lot come out ahead.