A ridge beam is the horizontal structural member at the peak of a sloped roof — supporting the top of every rafter. Unlike a ridge board (non-structural, used with collar ties), a ridge beam carries the load of the rafters and roof down to its supports. Ridge beam sizing and the supporting posts are engineered work — required for cathedral ceilings, additions, and major reframes.
This guide is an overview of ridge beam installation. Engineering, permits, and licensed crew are typical for new construction; not first-time DIY structural work.
Before you start
Three things to settle:
1. Engineered drawings before any cuts. Ridge beam size, post locations, post sizes, and connections must be engineered. Span tables in OBC Section 9.23 cover simple cases; larger spans or unusual configurations require engineer's stamp.
2. Continuous load path to foundation. Ridge beam load must transfer through posts to a beam below, then to a footing. Each post must align with structural support beneath. Skipping any element of load path = settling and structural failure.
3. Lifting heavy beams safely. Engineered LVL ridge beams: 80-200 lbs per linear foot. 16-24 ft beams: 1500-3000 lbs total. Lifting requires multiple people, mechanical lifts, or boom truck. Plan equipment before starting.
What you'll need
Tools
- Crane or boom truck (for heavy beams)
- Drill with bits and driver
- Level (4-foot)
- Tape measure
- Reciprocating saw
- Framing square
- Hammer or impact driver
Materials
- Engineered ridge beam (LVL, glulam, or steel — sized per engineer)
- Support posts (6×6 or built-up post — sized per engineer)
- Post connectors (Simpson AC or HCP)
- Joist hangers for rafters
- Lag bolts and structural screws (sized per engineer)
- Construction adhesive
Hire structural engineer for ridge beam design
Sizing depends on span, snow load, roof material, and load path.
Engineer's stamp on drawings: required for permit in Ontario.
Budget for an engineering fee on residential work — far less than fixing a sagging ridge later.
Step-by-step instructions
Verify engineered drawings
Drawings show: ridge beam size and material, post locations and sizes, connections, footing requirements.
Drawings stamped by engineer or BCIN designer.
Permit pulled before construction.
Build supporting posts
6×6 solid post or built-up post (multiple 2×6 nailed together).
Footings: typically poured concrete, sized per engineer.
Post-base hardware (Simpson) anchors post to footing.
Post must be plumb (vertical).
Set posts in position
Posts at each end of ridge beam location.
For long beams: intermediate posts at engineer-specified intervals.
Post height: top of post = bottom of ridge beam.
Verify post heights are equal (laser level).
Lift ridge beam onto posts
Mechanical lift or crane.
Position beam on top of posts.
Verify beam is level along its length.
Verify beam is centered over posts (don't overhang).
Anchor beam to posts
Post cap connectors (Simpson AC or HCP) at top of each post.
Lag bolts or structural screws per connector spec.
Beam locked to post; can't shift or lift.
Verify level along beam length
Laser level or 4-foot level along beam top.
Beam should be perfectly level.
Adjust post heights with shims if needed (within engineering specs).
Out-of-level beam = uneven roof line.
Cut and install rafters to beam
Rafters cut per engineering: ridge cut at top, seat cut at bottom (where rafter meets wall plate).
Top of rafter: hung on ridge beam via joist hangers (or face-nailed if engineered for that).
Bottom of rafter: anchored to wall plate via hurricane ties.
Verify rafter spacing and uniformity
Rafters at code-spec spacing (16 or 24 inches OC).
All rafters identical length and angle.
Sight along ridge from one end — should appear straight.
Add temporary bracing
Temporary diagonal braces from beam to walls or floor.
Holds beam in alignment during sheathing.
Remove after sheathing is complete (sheathing locks the system in place).
Schedule structural inspection
Building inspector verifies: beam size, connections, post sizes, rafter spacing.
Pass: continue with sheathing.
Fail: fix and re-inspect.
Common mistakes that cost you
- Wrong beam sizing. Sagging ridge, drywall cracks, eventual failure. Always engineer.
- Insufficient post support. Beam settles. Continuous load path mandatory.
- Crooked post installation. Beam not level, rafters uneven. Verify plumb.
- Skipping inspector. Structural work without inspection = code violation.
- Lifting heavy beam without proper equipment. Injury risk. Use crane or lift for heavy beams.
Frequently asked questions
Ridge beam vs ridge board?
Ridge beam: structural; carries rafter loads to posts. Used in cathedral ceilings, modern designs.
Ridge board: non-structural; rafters held by horizontal collar ties between opposing rafters. Older homes use ridge boards.
Engineering specifies which is used per design.
How long does ridge beam install take?
Typical residential: 1 day for beam install.
Plus rafter installation: another 1-2 days.
Plus sheathing: 1 day.
Total framing: 3-5 days for typical addition or cathedral conversion.
What does this cost?
Cost drivers: engineering and stamped drawings.
The engineered beam itself (LVL), sized by span and load.
Posts, connectors, and load-path hardware.
Installer crew labour, which scales with access and complexity.
Total varies widely with span, load path, and site conditions — get a written breakdown before committing.
When to call us instead
Ridge beam installation is engineered structural work. Our team coordinates engineering, permits, and crew for additions and conversions.
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