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Will Allen, EI| GHD

Hail Damage To Your Infrastructure? Using Insurance to Offset Project CostsNC AWWA WEA Spring Symposium

Agenda

• Background

• Weather event

• Types of hail damage

• Damage assessment

• Working with insurance

• Design and construction

• Project outcome

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Background

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North Fork Water Treatment Plant

• 31 MGD permited

• 15-17 MGD average

• Direct filtration water treatment plant.

• Burnette reservoir constructed in 1954

• Current facility built in 1976

• Main water source for the Asheville.

• A total of 7 buildings at the plant

• Roofs were covered with single ply, clay tile, and metal

Source: Google Earth

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Weather Event

How Hail Forms in a Storm

• A hailstone is developed in layers.

• Layers consist of transparent and translucent layers. Usually 0.039 inch in thickness. Layers are developed by rate of freezing, thus position in cloud.

• Usually irregular shaped and clumped together.

• Hail develops by cycling vertically in the cloud.

• Hail falls when the weight of hail overcomes the updraft or the cloud loses energy.

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Hail Storm at North Fork

• On April 1, 2016 a strong line of thunder storms impacted the plant.

• Operators reported golf ball sized hail (1.75 inches)

• USDA inspection of surrounding forest

Types of Hail Damage

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Threshold for Hail Damage

¾” - Old asphalt roofing, unsupported portions of asphalt roofing.

1”- Lightweight asphalt roofing

1 ¼” - Heavyweight asphalt roofing, wood shingles.

1 ½” - Clay, slate tiles, single ply membranes.

Threshold for damage is a level where the functional capacity of the roofing material is affected, but not to the level where the water shedding capacity is stopped or the anticipated life of the roofing materials is alternate/diminished.

What Does Hail Damage Do to Single Ply?

• Type of system at North Fork

• Most approaching 20 years old

• As a TPO roof ages plasticizers leak out and make it more brittle

• EPDM roofs are more resilient

• Insulation indentations can also happen

Typical Single Ply Roof System

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Hail Damage Observed at North Fork

HVAC Coil Damage Hailstone Spatter Insulation Indentation

Metal Indentations Cracked Membrane Overview of Cracked Membrane

Damage Assessment

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Damage Assessment

• GHD performed a hail damage assessment

• This was to provide backup incase of an insurance dispute.

• A 65 page report was written and stamped by a forensic engineer

• This assessment encompassed all the buildings on-site

• 5 buildings out of the 7 were found to have sustained damage

Working With Insurance

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Working With Insurance

• Included in the scope of work

• Site visit with insurance adjusters

• The City had its own risk department

Design and Construction

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Design

• The design of the roof was restricted to like kind materials

• GHD however, did use a TPA/KEEmembrane which is higher quality

• The roof system was improved with substrate and cover boards

• Added vapor barrier

• Fully adhered instead of mechanically fastened

• Fleeced backed membrane

• Improved the R-rating

Construction

• 90 day construction time

• Winning bid was $413,891.00

• Replaced 5 buildings to decking

• Minor repairs to clay tile and metal roofing

• Finished on-time with one change order

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Outcome

Outcome

• The project ended up costing $489,337.53

• Insurance paid approximately $120,000

• The City was able to get new roofs on all of their main buildings at the plant for $369,337.53

• Overall the project was a success and the City was able to save money in the process

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Will Allen, EI - will.allen@ghd.com

Questions

NC AWWA WEA Spring Symposium