Encompassing a variety of shapes, colours, and sizes, flagstone find common use in the construction of walkways, fence structures, roofing, and driveways. The pieces are often massive, thus earning the roots of it's Norse name from long ago: "flaga" meaning "slab of stone". The affordability, durability and density of the stone are making it more and more common in do-it-yourself projects but also make it difficult to drill; the process of drilling flagstone is necessary to install railing on the material.
Lay out the railing in the intended area of installation; mark several points in a straight line and then snap a line to connect the points for the layout. Do this if the railing is centred or in a straight line, off centre. Lay out the railing "system" if you find the railing separated in sections.
Measure the length of the first railing. Hold the railing section in place with the aid of a partner and mark the railing post's base (either part of the railing or a mounting plate) on the flagstone. Continue by marking the holes of the post's base. This is where the bolts, concrete anchors or fasteners will be installed that hold the railing in place.
Purchase or rent a hammer drill. Hammer drills come highly recommended for drilling flagstone because of the dense nature of the stone. Buy masonry bits capable of drilling the dense flagstone.
Place the hammer drill bit directly on marks from step 1 and slowly begin drilling. If the hammer drill is variable speed, start out at a lower speed and move your way up, maintaining precision and control of the drill.
Increase the speed of the hammer drill once the hole is started. Do not increase the speed to the point that the drill is difficult to manage. Drill down to the length of the bolt; it's acceptable to drill a little more than the length as well. Remove the impact hammer drill bit and test fit the anchor or bolt for the railing. Continue these steps until you complte all the holes for the railing's stands.
Attempt a test run of the first section of railing, using a partner or friend to help lift the railing. Line up the bolt holes with the holes drilled in the flagstone and confirm that the bolts fit. Check the railing for level and have a partner hold the railing level and in place to fasten it permanently in place.
Tighten the bolt or concrete anchor with a socket wrench. Use a crescent wrench for bolts that are more difficult to reach. Perform any additional necessary drilling with the impact hammer if the bolts do not fit. Attach applicable bolts or fasteners, double check for plumb (vertically level). Continue the steps on sections of railing until you complete the project.