Slate Roof Installation – Installing Slate

In this segment, we will start to install some slate.

A typical slate nail is a 10 or 11 gage smooth shank nail with a 3/8” head. The length is 2 times the thickness of the slate plus 1”. Proper nailing is critical to the durability of a slate roof. Slates are intended to hang on the nails with the head set slightly below the surface in the countersinks left by the nail hole punching. Over driven nails can weaken the nail hole by blowing out the back of the slate. Under driven nails can cause the course above to be lifted slightly which can lead to breakage or an uneven surface.

Slate Roof Installation: The Process

Beginning with the starter slate laid vertically on top of the cant, the size of the starter slate should be twice the length of the field slate. The height of the starter is the exposure length plus the head lap. The first course is installed over the starter, and will lay flat against the starter due to the cant. The following courses are laid in a staggered pattern across the roof following the layout lines. Here are some important tips to keep in mind:

• The slate should not be pushed tightly together. Maintain a slight side gap of 1/16” to 1/8”
• Blending the slate before stocking will produce a uniformed finished roof.

I hope this helped you understand the techniques for installing a slate roof.

For part 6 of our series, on Replace a Broken Slate, click here.

For more info visit www.slateassociation.org and become a member.