Installing a Traditional Slate Roof

VIDEO CLIPS: Slate Roof Installation Mistakes

STANDARD THICKNESS ROOF SLATES (3/16" TO 1/4") THAT HAVE DRILLED HOLES WITHOUT COUNTER-SINKING ARE SUB-STANDARD SLATES THAT SHOULD BE REJECTED, IF POSSIBLE. AFTER INSTALLATION, THE NAIL HEADS WILL RUB AGAINST THE OVERLYING SLATES AND EVENTUALLY WEAR HOLES IN THEM. ALWAYS CHECK BEFORE BUYING TO MAKE SURE THE STANDARD THICKNESS SLATES HAVE COUNTER-SUNK OR PUNCHED HOLES. IF NOT, DO NOT BUY THEM. THICKER SLATES DON'T MATTER SO MUCH IF THE SLATES ARE DRILLED AS THEY TEND TO NOT LAY SO FLAT AGAINST EACH OTHER AND THERE IS USUALLY ROOM IN BETWEEN THEM FOR A NAIL HEAD.

Download the diagram below as a PDF file (requires Adobe Acrobat)

Installing a slate roof.

What not to do when installing a slate roof.

slate roof installation - getting started

Download the above diagrams as a PDF file (requires Adobe Acrobat).

The above illustration shows basic installation details for a traditional, standard-thickness slate roof. The cant strip is variable in thickness according to the thickness of the slates being installed (thicker slates require a thicker cant strip). Gable edge projection and drip edge projection can also vary somewhat. Headlap is also variable. Greater headlap (e.g. 4") may be preferred when the roof slope is lower (e.g. below 4:12 to 6:12) or along eaves when ice damming conditions are prevalent.

There is much more information about installing slate roofs in the Slate Roof Bible or go to Traditional Roofing Magazine. Have questions? Post them on our message board!