Sizes
There are multiple sizes of glass blocks available – they are typically sold in standard installation sizes such as 4″ x 8″, 6″ x 8″, 8″ x 8″ (the most common size) and 12″ x 12″. There are also curved blocks which help build curved walls – for example you can order blocks with a 22.5° soft radius so 4 of them gives you a 90° angle.
All of these are available either 3 or 4 inch thicknesses. Most of the country uses 3 inch thick blocks, but Florida, Texas and many other coastal areas require 4 inch block for all exterior applications
Keep in mind that these dimensions are actually 1/4″ bigger than the actual glass blocks you ” x 7¾”.will receive because the spacers add 1/4″. So an 8″ x 8″ block is actually 7¾” x 7¾”.