Tips for Taking Down a Wall

Homeowners increasingly seek to open up floor space by removing interior walls. Before any interior wall is removed, it is essential to determine if the wall supports floor, ceiling or even roof framing. Such “bearing” walls can be removed only if some alternate method of support is provided for the framing above.

For a relatively new house, building plans (if available) may show interior bearing walls. However, as-built framing construction should always be verified visually before a wall is removed.

For many existing houses with rectangular floor plans, interior bearing walls can often be located by visual inspection. Tools such as stud-finders may be useful to obtain more information about direction of floor joists. However, ceiling finish must usually be removed to determine with certainty if an interior wall is in fact a bearing wall.

For older houses, built before 1950, and for houses with irregular floor plans, ceiling finish should always be removed to verify bearing wall conditions.

A bearing wall supports other parts (elements) of the house.Floor joists (such as 2x8s or 2x10s) or roof framing members (rafters or joists) are perpendicular to the bearing wall and are on top of (bear on) the wall.

For the vast majority of houses built since 1950, a ceiling is up against (attached to) the bottom edges of floor joists, even though some may describe the joists as ceiling joists. For older houses, separate ceiling joists are sometimes found (below floor joists).

Exterior walls that support floor joists (including attic floor joists) are bearing walls. However, even if an exterior wall does not support floor joists, it can still be a bearing wall if it supports roof framing (rafters or joists). Identification of such condition requires careful evaluation when floor joists and roof rafters run in opposite directions for a two-story house. The exterior wall below the second floor is a bearing wall if the rafters are perpendicular to the wall, even if second floor joists are parallel to the wall.

Installation of a “header beam” or “floor beam” is required to support floor or roof framing when a bearing wall is to be removed. For a short header (up to about 4 feet), double 2x10s or 2x12s are usually adequate. However, for a longer floor beam, proper design is essential to ensure safety and to minimize movement.

Accurate information about upper framing to be supported must be obtained to allow for proper design of a new header or floor beam.

Evaluation of vertical deflection limit is an important aspect of design that is often overlooked. Limiting deflection is critical when ceramic tile floor finish or other movement sensitive elements must be supported by the new beam.

Manufactured wood such as Laminated Veneer Lumber (LVL) and Parallel Strand Lumber (PSL) are often the most cost effective type of beam. LVL and PSL beams can be “built-up” using multiple pieces, allowing for easy installation. However, the separate pieces must be connected together to act as one unified beam, especially if the beam must support concentrated load from another floor beam.

For long beams (15 feet or more), and especially when deflection is critical, steel beams are often necessary. Design to minimize weight becomes important.

Support at ends of a new floor beam must be provided by columns (posts), which can usually be “built-up” using multiple 2×4 studs nailed together. Careful evaluation of how each column must be supported below is essential. Lower floor framing may have to be reinforced to provide adequate support.

In some cases, especially for long floor beams, new steel columns and footings must be installed in a basement to provide adequate support for a column that will support one end of a new floor beam.

Floor beams can be installed under floor framing. However, when protrusion below a ceiling is not desired, a “flush” beam must be installed. Design and construction of a flush beam is more complex and costly since floor joists must be cut back to allow for installation of the beam. To match depth (height) of existing floor joists, a heavier floor beam is often required (compared to low beam under floor joists).

For any beam that is over 5 feet, and especially when relatively heavy loads must be supported, drawings should be prepared to show requirements. Consultation with a qualified professional engineer (licensed in your state) is highly recommended.

Before removing a bearing wall, temporary support (shoring) must be installed to support floor or roof framing that is currently supported by the bearing wall. Temporary shoring typically consists of a wood-stud wall, on each side of the bearing wall. Top of the temporary wall must be tight against wood framing members (not ceiling finish that can crush).

Although a qualified contractor can often install temporary shoring without engineered design, consideration should be given to effects on lower floor framing, due to shifting of loads from the bearing wall (to be removed) to the temporary support walls.

For more articles by this author, please go to Helium.com

John F Mann, PE
Structural Support
1212 Main Street, Suite 2
Belmar NJ 07719
732-556-6080
jmann77@optonline.net

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