One of the major causes of roof structural failure is the excess weight due to snow.  Building code provisions are suitable for many new buildings; however, problems can occur if snow loads are not assessed correctly.

Snow loading consultation is valuable for the following:

Does the building have a large roof area?	Is there an unusually shaped roof?
Will snow load increase on surrounding buildings?	Will a tall adjacent building or feature (e.g., trees) increase snow load on proposed building?

Services

Building Code Assessment

The local building code, international building codes, and RWDIâ??s experience of snowdrifting are used to assess snow loads.  If unique drifting is anticipated, the Water Flume Enhanced Building Code Asseessment is carried out.

RWDI has assisted with updating the National Building Code of Canada.

Water Flume Enhanced Building Code Assessment

Water flume tests are conducted to determine if drift patterns are similar to the building code.  Observed patterns are compared to building code values or other known load patterns.  If accumulations appear to exceed building code values, loads would be increased.  If accumulations appear to be less than building code values, the Detailed Finite Area Element (FAE) Assessment is recommended.

Detailed Finite Area Element (FAE) Assessment

The FAE method is exclusive to RWDI, and we received an Award of Merit from the ACEC for the FAE method in 1986.

Detailed FAE assessments are conducted where:

• The building shape does not lend itself to a building code assessment
• Accurate design snow loads are critical in the building design
• Snow loads lower than building code values are required