A roof inspection revealed that this Omaha church's Mottled Green and Purple slate had not been installed correctly; the slates had been nailed and overlapped incorrectly. In addition, two of the roof valleys - areas where sections of roof meet - were "closed", indicating that no metal was showing. Because each roof had a different pitch, water cascading down the steeper slope had a chance of slipping behind the valley of the opposite roof, creating a leak. Thankfully, the heavy underlayment caught any infiltrating water and prevented interior damage.
The beautiful Mottled Green and Purple slate was approximately 15 years old and quarried from around Poultney, Vermont. This area started quarrying slate in 1839 and continues to this day. The various shades of purple suggest these slates were quarried from different sources within the area.