2012-3-1-old-and-new-hail-damage

Wind Effects on Hail Velocity and Impact Energy

DonanEngineering Articles, Commercial & Residential Roofing, DamageRecon, Forensic Engineer, Forensic Engineering, Hail and Wind, Registered Roofing Consultant

The relationship between wind, hailstone velocity, and impact energy is based on an understanding of fundamental physics. Over a half century of laboratory research and field studies have determined that the severity of hail damage to a roofing material is contingent on the kinetic energy at the point of impact and the roofing material’s resistance to that impact energy. These …

86a-3-tab fiberglass-mat asphalt shingle, intentional coining 2  Warren

Tips for Identifying Intentional Roof Damage

DonanEngineering Commercial & Residential Roofing, Forensic Engineer, Forensic Engineering, Hail and Wind, Registered Roofing Consultant, Roofing Investigations

Part 1: Suspicious Damage Patterns Not Caused by Hail An important tip for identifying intentional roof damage, which is made to mimic hail damage to a shingled roof, is to observe the locations and patterns of the damage.  The patterns can be observed by circling each damaged location and then connecting the locations together with chalk lines. The location of …

Photograph 1: Hail impacts cause blemishes that vary in size, shape, and characteristics.

Tips for Identifying Intentional Roof Damage – Part 2

DonanEngineering Articles, Commercial & Residential Roofing, Forensic Engineer, Forensic Engineering, Hail and Wind, Registered Roofing Consultant, Roofing Investigations

Part 2: Suspicious Damage Characteristics Not Caused by Hail An important tip for identifying intentional roof damage, which is made to mimic hail damage to a shingled roof, is to observe the characteristics of individual blemishes on the roof.  Examining close-ups of high resolution digital images is a useful method of determining whether a blemish was caused by hail, or …

How-to-Reduce-Condensation-in-Your-Conservatory

Condensation, Dew Point and Winter

DonanEngineering Articles, Commercial & Residential Roofing, Forensic Engineer, Forensic Engineering, Structural Damage & Collapse, Water Losses, Winter Storm

Most people know in a general sense what condensation is, and some may even have an understanding of its cause given their experience and perhaps a recollection of high school science.  These same folks may also know that there is a connection between condensation and the terms “dew point” and “relative humidity,” but that is usually where most people’s knowledge …

Photograph 1

Corrosion of Aluminum Flashing in Contact with Pressure Treated Wood Decks

DonanEngineering Articles, Forensic Engineer, Forensic Engineering, Structural Damage & Collapse

When decks are attached to a house, flashing is installed under the siding and over the deck joist attached to the rim joist of the house to direct water away from the joists. The deck joist is normally pressure treated wood and the rim joist is not normally pressure treated wood.  If the flashing fails the rim joist is exposed …