A saddle hip is when the cap slate is installed over the finished slate roof on either side creating a saddle effect. They are the most common hip detail used for slate roofing. The size of the slates depends on the field slate size. In general, the long dimension of a saddle hip slate should be approximately twice the exposure of the field slates. The short dimension should be approximately the exposure of the field slates, rounded up to the next standard slate size. The thickness of the hip slates typically matches that of the field slates. Generally, New England Slate provides cut-to-size hip slates to the roofer. Because the nail hole(s) location on saddle hip slates will depend on the size and location of the wood nailers and installation of the field slates, hip slates are normally supplied unpunched to allow for custom punching in the filed. The most robust nailing consists of a minimum of three nails set in triangle pattern. The triangle pattern is very rigid. It helps to balance the gravitational forces acting on the slate, with some of the nails acting as pivots and others as fulcrums.
The National Slate Association, Slate Roofs: Design and Installation Manuel 2010 edition is a great resource for design details, specifically pages 142-156 for hips.
Tell us if you prefer installing saddle hips & why and we’ll send you a New England Slate “I’d Nail That” shirt.
Thank you for reading!