09-22-12

Structural Repair Claims: Live Loads vs. Dead Loads

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Live Loads vs. Dead Loads

Live loads – refer to loads that do, or can, change over time, such as people walking around a building (occupancy) or movable objects such as a flower pot on a deck.   In addition to live loads, environmental loads are loads that are created naturally by the environment and include wind, snow, seismic, and lateral soil pressures.

Dead loads – refer to loads that typically don’t change over time, such as the weights of materials and components of the structure itself (the framing, the flooring material, roofing material, etc.), and the weights of fixed service equipment (plumbing, HVAC, etc.).

“When repairing a structure, most building departments will require that the damaged area be brought up to code, or at least the items that are being repaired or replaced.  A home built in 1970 with damaged roof trusses should not be simply repaired with the same 2×6 size rafters that were installed when it was built. An engineering analysis must be performed to ensure the repaired roof meets the requirements of the code currently enforced.” – Lauri Stankewicz, M.S., E.I.

Building Codes and Governing Codes
Building codes – refer to a set of International Codes developed by the International Code Council (ICC) which umbrellas the following code sets: the International Building Code (IBC), the International Residential Code For One- and Two-Family Dwellings (IRC), the International Plumbing Code (IPC), and the International Mechanical Code (IMC).

Governing codes – encompass the building code that each building department enforces, as well as any specific requirements enforced in a given municipality (such as environmental loads). Most often, governing codes include amendments to the building code

“As far as structural claims go, make it a habit to first check with the local building department where the building in question is located in order to determine which code set is enforced. It is equally important to check with the building department, as they may also issue specific requirements pertaining to the environmental loads. They stipulate these requirements based on standards set forth in the IBC, but each building department can ultimately enforce the environmental loads as they see fit for the safety of their community”. –  Lauri Stankewicz, M.S., E.I.

In addition to determining which building code set is applicable to your specific claim, the following building design factors also need close consideration: 

  1. The risk, or occupancy category: refers to the type of habitation the structure is being used for to determine the risk to human life if the structure were to fail in some way.   For example, a structure that is used to store hay compared to a structure that is used as an elementary school would be in significantly different risk categories, as an elementary school contains more elements of safety for human life.
  2. Dead load factor: which takes into consideration the types of materials used to build the structure and the associated material weights.  While most single family homes are made out of wood framing materials, commercial structures can vary from wood, to metal, to concrete.
  3. The design of live loads: what is the purpose and use of the structure? What are the live load requirements for the structure? For example, a single family home, a restaurant, and a stadium would all have different live load requirements. Moreover, the IBC lists live load requirements for differing rooms within a structure.  A library has a higher requirement for live load in a room where books are stacked versus a room that’s designated just for reading, because rows and rows of books weigh a lot more than a few people each reading one book while sitting on some chairs.

 

”When it comes to environmental loads, the IBC specifies different requirements depending on location.  In California, seismic load requirements would govern in structural design instead of snow load because an earthquake is more feasible than a three-foot snow storm.    In the Rocky Mountains, snow load requirements would govern for obvious reasons.  Moreover, local municipalities can modify loads, so the wind load in Denver may differ from the wind load in Colorado Springs, or the snow load in Vail may differ from the snow load in Aspen.” – Lauri Stankewicz, M.S., E.I.

This article was originally published September 2012 by Property Loss Research Bureau (PLRB). Serving the insurance industry, PLRB  is a non-profit organization specializing in claims research. Reproduced with permission from PLRB.

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