Knott Laboratory provides forensic engineering and animation, Civil & Structural, and Fire & Explosion Investigation services to reconstruct accidents.
A Homeowner’s Guide to Structural Engineering Terms
A glossary of terms
As a homeowner or HOA, encountering structural damage or degradation on your property can be a daunting experience. Understanding the basic language used in structural engineering reports is crucial for making informed decisions about repairs and renovations. To help, we’ve compiled a glossary of terms commonly found in such reports:
Building Envelope: The exterior components of a building, including the walls/wall cladding, roof, windows, doors, and foundation, which collectively protect the interior from weather and environmental elements.
Foundation: The lowest part of a building that transfers the building’s gravity and lateral loads to the ground. The foundation extends below the frost depth to protect the structure from freeze/thaw movement. Common types include spread footing, micropiles, and caissons.
Settlement: The gradual sinking or shifting of a building’s foundation, often caused by soil consolidation or subsidence or overloading from the structure.
Soil Compaction: The process of mechanically increasing the density of soil to improve its load-bearing capacity and reduce settlement potential.
Erosion Control: Measures taken to prevent the loss of soil due to wind, water, or other environmental factors.
Cracking: Fractures or breaks in the building materials, which can indicate structural issues such as settlement, foundation movement, or excessive loads.
Shear Wall: A vertical structural element designed to resist lateral forces such as wind or seismic loads. They transfer lateral loads from roof diaphragm to floor diaphragm, floor diaphragm to floor diaphragm, and floor diaphragm to foundation in some cases.
Retaining Wall: A structure designed to retain soil, preventing it from eroding or collapsing and supporting vertical or near-vertical grade changes. Retaining walls over 4 feet tall are required to be designed by an engineer.
Reinforcement: Steel bars or mesh embedded in concrete to increase its tensile strength and/or resist surface cracking.
Footing: The base of a foundation wall or column that spreads the load from the structure over a larger area of soil.
Beam: A horizontal structural member that carries loads across open spaces, such as between columns or walls.
Column: A vertical structural member that supports loads from beams or slabs above and transfers them to the foundation.
Expansion Joint: A flexible joint used to accommodate the expansion and contraction of building materials due to temperature changes. Ie. Vertical stucco to siding transition.
Flashings: Waterproof materials installed to prevent water penetration at joints, seams, or transitions in the building envelope, such as roof edges and wall intersections. Galvanized metal is commonly used for exterior flashing applications.
Joist: Horizontal structural members that support floors and ceilings, usually arranged parallel to each other and spaced at regular intervals. A couple common joist materials are wood 2x material or pre-engineered joists.
Truss: A framework of top/bottom chords, vertical/diagonal webs, and gusset plates (intended to connect the chords/webs) designed to support loads over large spans, commonly used in roofs and floors.
Sagging: A downward deformation of a structural member due to excessive loads or inadequate support. Often synonymous with deflection; sagging typically refers to older structures.
Deflection: The bending or deformation of a structural member under load (usually worst at beam midspan), measured as the displacement from its original position.
Corrosion: The gradual deterioration of metal due to chemical reactions with its environment, such as rusting in steel members/reinforcements.
Load-Bearing: Refers to elements of a structure that support the weight of the building and its contents, transferring it down to the foundation.
Load Capacity: The maximum amount of load a structure or component can support safely without failure.
Load Path: The route by which loads are transferred from one part of a structure to another, typically from the roof to the foundation, ensuring stability and safety.
Lateral Load: Horizontal forces acting on a structure, such as wind or seismic loads, which can cause it to sway or deform.
Dead Load: The static weight of the structure itself, including materials, fixtures, and permanent components, exerting a constant downward force.
Live Load: The dynamic or movable weight imposed on a structure, such as furniture, occupants, and temporary loads, which can vary over time.
By familiarizing yourself with these terms, you’ll be better equipped to understand structural engineering reports and communicate effectively with engineers, contractors, and other HOA members involved in the reconstruction process. Remember, proactive maintenance and timely repairs can help preserve the integrity, safety and value of your property for years to come.