All glass used for deck rails must be safety-tempered and shatter-resistant. Also, always make sure that all the edges of the glass are polished to prevent anyone from getting cut. Before building a glass deck rail, you should check with your local building department to enquire about any local restrictions. Most deck builders use tinted glass to match the house windows and as a deterrent to birds accidentally hitting them.
You may need to do some research to find a local glass company that can manufacture a custom glass order for you. Glass is priced as a commodity that does fluctuate in price. You should be able to buy glass for a deck rail for about $40 per lineal foot. When ordering, you will need to provide the exact measurements of each piece and the thickness. Using glass railing is an interesting choice that wonderfully preserves views. However, glass is very expensive and is only used in selected positions around the deck.
Installing glass rails will usually require you to build the rail frame first and take precise measurements to custom order the tempered safety glass. Because glass is very heavy, we recommend spacing the rail posts no more than 5 feet apart. Using a wood top and bottom rail, you will need to create a channel to place the glass in by using a router. The channel will usually be 3/8” thick and 1/2” deep to support the glass. You will need to subtract about 3” from both sides of the opening when ordering the glass to leave space for your hands during installation. Sometimes, it makes sense to install a piece of blocking or a brace under long rail spans for extra support. Installing tempered glass into stair rails is possible but very difficult. If you are going to try this, you should trace the opening on a large piece of cardboard to make sure you get the angles right.