Can I Side over a Slate Siding?

Slate Shingles

• Slate shingles became a desirable siding material in the late 19th century. In areas with a ready supply of slate, such as Vermont, houses with slate shingles were quite common. Installed just like a slate roof, slate siding was nailed one shingle at a time in an overlapping pattern. Often, bands of red or green slate would accent a wall. As with wood shingles, slate walls often boasted specially cut shingles to make attractive patterns.

Condition

• In addition to slate's natural durability, vertical installation means that a lot of slate siding is still in good condition. In fact, most survivors have outlived the matching slate roofs that once sat atop them. Some, however, are broken from fallen branches or careless ladder users. Missing slates allow water to rot the substrate, causing more slate to fall off. Some applications are riddled with holes from previous siding projects.

Siding over Slate

• Applying new siding over slate is not a good idea. The presence of slate hinders any efforts to replace rotting sheathing, add insulating panels and apply house wrap. If slate is missing, it creates an uneven nailing surface. When nailing slate, in fact, you will likely break many pieces, with some of them falling on and marring finished siding below. Worse, falling slate is heavy and sharp and can injure workers below. The best thing is to remove the slate before starting the new project.

Removing Slate

• Removing slate is similar to most other siding removal projects. You'll need to start from the top and work your way down. The job produces a lot of mineral dust, so you'll need to use a dust mask or a respirator. If your slate shingles are in good condition, consider recycling them. Old slate in large quantities is in high demand in areas with a lot of houses with old slate roofs. Local slate roofers and slate roof owners are often willing to remove slate themselves if the slate is in good condition. An Internet ad will draw a lot of interest from many people for a decent supply of slate.