Why garages cause building losses
Garages under and beside downtown buildings are usually unheated or only partly heated. In a hard cold snap, water-filled piping that passes through them, such as domestic lines, wet sprinkler branches or drains, can freeze even when the occupied floors above stay warm. Many garage sprinkler systems are dry-pipe systems for this reason, but they still rely on drained low points and working compressors to stay that way.
Garages also receive water from above. Snowmelt carried in on vehicles, plaza and deck drainage, and storm runoff all flow through garage drains to sumps or the sewer. When a drain line clogs or a sump pump fails during a heavy storm, water can back up into storage rooms, elevator pits and electrical rooms on the lowest level.
Finally, de-icing salts carried in by cars are hard on concrete and embedded steel. Long-term leaking through a deck can carry those salts into structural elements, which is a slower kind of damage that an engineer, not a restoration contractor, should evaluate.
Garage points to inspect after a cold snap or heavy storm
- Dry-pipe sprinkler valve rooms: heat working, low-point drains serviced per the fire protection vendor's schedule.
- Domestic water and hose bibb lines running through unheated areas.
- Trench drains and catch basins clear of debris and ice.
- Sump pits: pumps running, alarms working, discharge lines not frozen.
- Elevator pits at garage levels dry.
- Storage cages and bike rooms for tenant property sitting in water.
- Electrical rooms and transformer vaults on the lowest level dry.
How a garage freeze loss often plays out
- During the freeze
- A section of pipe freezes in an unheated corner. Nothing is visible yet.
- When temperatures rise
- The ice plug thaws and a split pipe begins to leak or discharge, often at night or over a weekend.
- First hours
- Water flows across sloped decks toward drains, and into any room at a low point: storage, electrical, elevator pit.
- Discovery
- A parker, security patrol or flow alarm reports it. The zone or line is shut and the break located.
- Following days
- Extraction, drying of affected rooms, replacement of damaged pipe and insulation, and inspection of any wet electrical or elevator equipment.
Planning ahead
Add garage heat-trace, heaters and sump alarms to the building's cold weather checklist, and walk the garage before forecasted cold snaps. Keep a map showing where every water line and sprinkler zone in the garage can be shut off, and share it with security staff who are present at night.
General information for Downtown Denver, not a quote or professional advice. In an emergency, call 911.