Known Issue 453
For a specific combination of Roof Year Built and Roof Covering Secondary Risk Characteristic (SRC) selections, the resulting modification to the hail damage function is larger than intended.
| Issue ID | 453 |
| Summary | For a specific combination of Roof Year Built and Roof Covering Secondary Risk Characteristic (SRC) selections, the resulting modification to the hail damage function is larger than intended. |
| Description | The current version of US Severe Thunderstorm model
varies the building vulneraiblity impact of Roof Year Built based on
the Roof Covering. Generally the building vulnerability gradually
becomes larger as the Roof Covering age increases. This
vulnerability change manifests each year along the functional
lifespan of the Roof Covering. A small subset of these years
manifest a more conservative (larger) vulnerabliity than
intended.
The typical unintended vulnerability increase is around 1% for most combinations, but may be as much as 5% for the Clay/Concrete Tiles option. This issue only affects vulnerabilty to the hail sub-peril. The straight-line wind and tornado sub-perils are unaffected. Because this issue only affects a small subset of Roof Ages and Roof Covering combinations, the impact to a portfolio composed of typical industry exposure is likely to be minimal or negligible. This issue is only triggered when both Roof Covering and Roof Year Built are both populated with the specific affected combinations shown below. The selections are: • Slate (5) - 2002 or 2011 • Built Up Roof with Gravel (6) - 2004 or 2012 • Built Up Roof without Gravel (9) - 2006 or 2012 • For Non-Engineered constructions only (Typically Wood and Masonry construction types, see model documentation): Clay/Concrete Tiles (3) - 2002 or 2011 Note that Year Built and Roof Year Built are different features, the former being a Primary Characteristic and not affected by this Known Issue. |
| Resolved in | Future software version |
| Date posted | 10/10/2025 |
| Software versions affected | 13.0 |
| Feature set | Detailed loss |
| Models | Severe Thunderstorm: US |
| Potential for loss numbers impact | Yes |
| Workaround | Degree of loss change at porrfolio level for
typical industry-composed exposure should be negligible and no
actions need to be taken. For portfolios with a heavily weighted
composition to the referenced combinations, or for individual risk
assessment workflows a revised Roof Year Built as follows may be
used:
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