New Hanover Schools
- SF: 52,700
- Wilmington, NC
- Unresolved Leaks
Our engineers found that the building had significant outdoor air leaking into the building all along the roof-wall transition resulting in excess humidity, sagging ceiling tiles, and high utility bills.
Gaps in the air barrier system are apparent at the roof-wall transition that is hidden behind the rain gutters. The infrared image above shows that the masonry wall temperature near the air leak is 22°F warmer than the area of the wall not warmed by the air leak. This is a significant heat loss condition and is typical around all similar areas of the building.
A view of the roof wall transition above the ceiling tile in the media center demonstrates the breach in the air barrier system. Also, the missing top plate (based on the plan drawing) allows the air space behind the vented brick cladding to communicate directly with the interior of the building.
Moisture leaking in from the ceiling was not caused by roof leaks at all. Instead, an ineffective air barrier was the primary source of the problem. The humid air was entering the
roof assembly at multiple locations from inside the school and, because there was no effective air barrier, the humid air was transported all the way to the standing-seam metal roof, where it condensed during colder weather and dripped back into the conditioned attic space.
Rust stains from water leaks are seen all along this roof truss under the metal deck seam.
The leak was an active drip through the structural metal decking – even though it had not rained in at least 4 days. The drip was located at a seam in the metal decking (black arrows). Rust on the truss is evidence that this is a recurrent site of dripping. The condensation site is not visible; the condensation site is the bottom of the standing seam metal roofing. Water vapor in the roof assembly condenses on the bottom of the metal roofing and then drips downwards until it finds an exit through the metal decking.