Hidden water damage can be a big deal because what you don't see grows
When plumbing lines burst, people notice. Unfortunately, a lot of the moisture damage in houses has nothing to do with bulk water. Instead, moisture trickles into houses through capillarity, air pressure, and diffusion creating hidden moisture damage.
To be sure, bulk water damage is a huge problem, but this article is about slow and steady, stealthy damage of water sneaking in the back door. And not leaving.
The EPA Water Management Guide is a comprehensive resource covering well over 100 pages. We're going to save you some trouble and consolidate this research into a concise hit list for you to execute in the field.
In Chapter 1, the EPA outlines four key elements of understanding the sneaky side of water:
What the symptoms of water damage look like: bugs, mold, rot, rust, efflorescence, spalling, peeling paint, failed floor adhesive, etc.
Where hidden water comes from: rain, surface, ground, humidity (inside and outside), plumbing leaks, sewer lines
How it travels: capillarity, gravity, surface tension, air currents, diffusion
Which parts of the system break most often, based on what has failed in the past: site drainage, gutters, siding, flashing, condensate drainage, humidity controls
This series of articles bundles those thoughts into a practical handbook for keeping houses dry.
Three targets for your design hit list: