Buildings are designed to withstand a certain level of expected forces, like gravity and wind, based on their location and function. Forces such as strong winds, earthquakes, or explosions can cause a building to move beyond what the materials are designed to withstand, causing significant damage to the interior finishes of the structure, even without a breach of the building envelope. Knowing how these forces can impact your building are the first step to protecting them before the damage is caused, or repairing them afterward.
Building loads
Several types of loads affect the structural integrity of buildings and can impact the interior finishes.
- Dead loads are relatively consistent, static loads such as the weight of the building and its mechanical systems.
- Live loads are those that change, like the weight of people in the building or environmental loads like snow or ice on the roof.
- Lateral loads, like wind, shift the building horizontally. All buildings are designed to move in the wind. How much a particular structure can move without causing damage is based on factors such as the design, building height, and the materials used.
- Seismic loads cause multi-directional movement, starting at the foundation and traveling vertically through the building. Structures in earthquake-prone areas are reinforced to withstand these types of forces.
- Impact loads, like an explosion blast wave or moving object, are beyond what structures are normally designed for and can significantly damage the building’s interior and exterior.
- Environmental loads, such as snow, frost heaves, rain, and ice can damage or deform the structure or the roof, causing interior damages even when the envelope is not breached.
Building movement
Buildings and their materials are designed for some amount of movement from any of these forces. When the movement is significant (from a particular event like a hurricane or earthquake), the materials used are brittle, or age has weakened a material, owners and occupants will start to see damages to the interior finishes.
Building materials can move in several different ways, and that may impact what kind of damage is caused and what the damage looks like.
- In plane, in the same direction as the material’s dominant section, like a panel moving along its face
- Out of plane, perpendicular to the material’s dominant section
- Deflection, such as bending of floors and roofs
- Thermal expansion and contraction of interior and exterior materials
- Hygrometric (moisture) expansion and contraction of wood and gypsum
- Settling—sudden or gradual subsidence of the ground under a building, causing deformation of external and internal building components
- Uplift—upward bowing of roof trusses from wind load, or variable moisture or temperature conditions
Damages to interior finishes
When forces act on a structure and move it beyond what the materials are designed to do, even without a breach of the building envelope, this can significantly damage interior finishes. Common damage can show as:
- Defects, such as ridges or blisters at the edges or joints.
- Cracking, splitting of finishes caused by differences in how building components move and respond to force.
- Joints, typically caused by building movement, thermal or hygrometric expansion or contraction
- Field cracking may be over a structural element or near doors, windows, or other areas where the surface is weak or penetrated
- Angle cracking at wall-ceiling joints typically caused by movement of the structure
- Crushing is typically caused by excessive load
- Degradation is the breakdown of building materials as they move repeatedly over time
Before repairing interior damages, it is critical to understand the underlying cause—fixing damages from a one-time event is very different than restoring sub-standard materials or installation that failed because they were inadequate for the job. The best way to ensure you understand what happened and rebuild properly is to work with a forensic architect or engineer, who can investigate the cause and origin of the damages, recommend the best materials for rebuilding, and provide you with expected scope and budget for the repair project.
Contact us today to get answers to your questions about damages to your interior finishes.
