A load-bearing wall supports the weight of the structure above it, while a non-load-bearing wall is little more than a room divider. Removing a non-load-bearing wall is routine, but taking out a load-bearing wall without replacing it can end in sagging floors, cracked finishes, or collapse. The standard solution is a load-bearing beam: a horizontal member that spans the opening and transfers the load to posts or columns, which carry it down through the foundation into the soil. Understanding how these members work, what they are made of, and how they are installed separates an open floor plan from a structural failure. The basics of how loads travel through a building are covered in our overview of load-bearing structures.
What Is a Load-Bearing Beam?
A load-bearing beam does the job of a load-bearing wall without occupying the space. It extends across the gap where the wall once stood, resting on posts or columns at each end and at intermediate points, and it carries the floor and roof loads that the wall used to support.
How a Beam Replaces a Wall
The wall transfers its load straight down to the foundation. The beam collects that load across its length and delivers it to discrete bearing points, so the structure below must be reinforced at those points with columns and footings sized for the concentrated loads.
The Load Path
Roof and floor loads travel from the framing members to the beam, then to the posts, then to the footings, and finally into the soil. Every link in that chain has to be designed for the loads it carries. A beam sized correctly but sitting on undersized footings will settle and crack the finishes above.
Beams vs. Headers and Lintels
A header spans a door or window opening within a wall and carries only the load directly above it. A beam spans a much larger opening and carries a bigger share of the structure. Lintels perform the header role in masonry walls. The sizing rules differ, and mixing them up is a common source of under-designed openings.
Confirm the Wall Is Load-Bearing First
Before planning a beam, confirm which walls actually carry load. Our guide to identifying load-bearing walls walks through the visual clues: walls running perpendicular to the joists, walls stacked above other walls, and walls sitting directly over the foundation are all likely candidates.
Beam Materials Compared
The three main beam materials are wood, steel, and concrete, and each one suits different spans, budgets, and construction types.
Solid and Engineered Wood
Wood is the most common residential beam material. Solid sawn lumber works for modest spans, while engineered products such as laminated veneer lumber (LVL), glued laminated timber (glulam), and parallel strand lumber (PSL) carry longer spans with predictable strength. Engineered wood is cut to order, arrives straight, and resists the warping that plagues large solid timbers.
Steel Beams
Steel I-beams and W-shapes offer the highest strength-to-weight ratio of the common options, which means smaller members for the same span. Steel is the usual choice for long clear spans and heavy loads. It needs fire protection in most residential applications, typically a layer of gypsum board, and the connections require welding or bolting by a qualified fabricator.
Steel I-Beam Basics
The I-shape puts the bulk of the material in the flanges, where bending stresses are highest, and the web ties the flanges together and resists shear. Steel beams arrive in standard shapes and sizes, and the correct member is selected from span-load tables or an engineer’s calculation rather than by guesswork.
Concrete and Precast Beams
Reinforced concrete beams are common in commercial and industrial construction, where their fire resistance and durability justify the weight. Precast concrete beams are manufactured off-site and lifted into place with a crane, which limits their use in residential remodels where access is tight.
Fitting and Connection Details
The connection details and fitting sequence shown in this Fine Homebuilding installation guide apply regardless of the material you choose, and they are worth reviewing before you commit to a plan.
| Material | Best Spans | Strength | Notes |
|---|---|---|---|
| Solid wood | Up to 12 to 16 feet | Good | Easy to cut and fasten; prone to warping at large sizes |
| LVL / glulam | 16 to 40 feet | High, predictable | Cut to order; used in most residential remodels |
| Steel | 20 to 60+ feet | Highest | Needs fire protection; professional fabrication |
| Concrete | 20 to 50+ feet | High | Heavy; requires a crane; fire resistant |
Types of Beams and Support Systems
How the beam is built and how it bears on the supports matter as much as the material.
Solid vs. Built-Up Beams
A solid beam is a single member, while a built-up beam is made from multiple pieces of lumber fastened together with nails, bolts, or adhesive. Built-up members are easier to handle on site and can be assembled from stock lumber, but the fastening pattern must be engineered. The design, construction, and load-bearing principles behind built-up beams are laid out in our dedicated guide.
Posts, Columns, and Bearing Points
The beam transfers its load to posts or columns at the bearing points. Wood posts sit on metal post bases bolted to the concrete, and steel columns are welded or bolted to base plates. Each post delivers a point load that the footing below must be sized to carry.
Column Footings
A spread footing distributes the point load over enough soil area to stay within the soil’s bearing capacity. The footing is typically wider than the column, reinforced with rebar, and poured below frost depth so frost heave cannot lift the column.
Flush Beams vs. Dropped Beams
A flush beam sits level with the joists, which are hung from it with joist hangers, giving a flat ceiling. A dropped beam sits below the joists and creates a visible soffit in the ceiling. Flush beams preserve headroom but complicate the framing; dropped beams are easier to install and are common in basements.
Sizing, Loads, and Foundation Capacity
Sizing a beam means adding up the loads it will carry and matching the member to the span.
Dead Loads and Live Loads
Dead loads are the permanent weight of the structure: framing, flooring, ceilings, and fixtures. Live loads are the temporary weights of people, furniture, and stored goods. Residential building codes typically assume a live load of 40 pounds per square foot for floors, and the beam must support its tributary area, the portion of the floor and roof it carries.
Span and Depth Rules of Thumb
For wood beams, a common rule of thumb is a depth of about one-twentieth of the span: a 16 foot span needs roughly a 10 inch deep member, which usually means an engineered beam or a doubled 2×10 or larger. Steel beams can be shallower for the same span. These rules only size the initial guess; the final member comes from span tables or an engineer’s design.
Soil and Footing Capacity
The load path ends in the soil, so the ground has to be able to take the load. When conditions are uncertain, a plate load test to calculate bearing capacity and settlement gives the numbers needed to size footings with confidence instead of guessing.
Typical Soil Bearing Values
- Clay: 1,500 to 2,000 pounds per square foot
- Sandy soil: 2,000 to 3,000 pounds per square foot
- Gravel: 3,000 pounds per square foot and up
- Rock: 10,000 pounds per square foot or more
Installation Steps and Support Details
Installing a beam in an existing house is a demolition and construction job in one, and the sequence matters.
Plan, Permit, and Engineer Review
Start with a structural engineer’s design and a building permit. The engineer specifies the member size, the bearing details, and the footing sizes, and the permit ensures the work is inspected. The beam carries the structure while the exterior enclosure stays a separate, non-load-bearing assembly, the same division of labor used in curtain wall systems on commercial buildings.
Temporary Shoring
Before the existing wall comes out, build temporary support walls on both sides to hold the structure above. Temporary walls are framed with studs and wedged tight against the floor and ceiling, and they stay in place until the beam and its posts are installed and bearing.
Shoring Sequence
- Frame temporary stud walls on both sides of the wall being removed
- Wedge the top plates tight against the ceiling structure
- Remove the existing wall in sections, leaving the studs until the opening is ready
- Set the beam on its bearing points with jacks or helpers
- Plumb and brace the posts, then remove the temporary shoring
Setting the Beam and Making Connections
The beam is lifted into place, seated on its bearing points, and connected with nails, bolts, or welds depending on the material. Flush beams get joist hangers on each joist; dropped beams rest directly on the posts. Post bases are bolted to the footing, and the posts are fastened to the beam with metal connectors that resist uplift and lateral movement.
Fire Protection and Finishing
Steel beams in homes need fire-rated covering, usually one layer of gypsum board with taped joints. Wood beams can stay exposed in many assemblies, though local codes may require protection in attached garages. Box the beam in with drywall or leave it exposed as a design feature, then finish around the new column with trim.
Load-Bearing vs. Non-Load-Bearing Walls
Knowing the difference before you swing a sledgehammer is the whole game.
Signs a Wall Carries Load
Walls that run perpendicular to the ceiling joists, walls with joists lapping or ending above them, walls stacked directly over other walls, and walls with a foundation or beam below are all likely load-bearing. The step-by-step process for how to tell if a wall is load bearing is laid out in our practical guide for homeowners and remodelers.
What Happens If You Remove the Wrong Wall
Remove a load-bearing wall without support and the floor above sags, cracks appear in drywall and tile, doors stop latching, and in the worst cases the structure collapses. Repairing that damage costs many times what the beam would have cost up front.
Permits and Professional Help
Most jurisdictions require a permit for structural work, and the inspector will want to see the engineer’s drawings. A general contractor handles the shoring, demolition, and installation, and a structural engineer stamps the design. Budget for both before the project starts.