Common, Yet Wrong Methods of Slate Roof Repair
Here are some common methods used to repair slate roofs employed by roofers (non slate roofers):
- copper hanger
- nail and bib
- roof cement
- face nailing w/caulk or roof cement
1. Copper Hanger
Copper hangers or copper straps are probably the closest method of repair to hooks.
(image 1) Single folded copper tab.
These tabs are installed a lot like hooks. Except some worker on a rainy day sits and cuts strips of copper. These hooks are nailed into the roof and the tab is created by folding the copper up over the front of the slate. In most cases, the copper is folded over creating a double layer tab. Unfortunately, these tabs are not always consistent and both single layer and double layer copper tabs will be present on the roof. The real problem is these tabs unfold when snow or ice sits on the roof. Once the tab unfolds, the slate will often slip out.
(image 2) Double folded copper tab. (same roof)
(image 3) Unfolded copper tab. (image 4)
The copper tab in image three was obviously the first thing noticed when examaning the roof. This tab is starting to unfold and eventually, the slate will slide out. On the same roof, there are two previous repair that were done with slate hooks. They are a little harder to see, especially from the ground. These are galvanized hooks, which turn a dull gray and blend into the roof very well.
2. Nail and Bib
Here, a replacement slate is slid in place. The keyway (space or slot between two adjoining slate) is unabashadley damaged by the roofer when nailing the slate in place. See the "dimple" created? Also of note, the nailhead is visisble. A sheet metal bib is then placed beneath the slate to cover the nailheads. Unfortunately, the damage from the careless application of the nail is etched in stone.
In this instance, the bib rusted away resulting in an unfortunate leak.
Rusted through bib. No, these cannot be used to view the solar eclipse without damaging your eye. These will result in a damaged ceiling, afterwhich you might be seeing stars when the repair bill arrives.
Roof cement and other sealants should not be used on slate roofs, except in specific circumstances, like the installation of a ridge or hip. Nothing says quality like roof cement on a slate roof.