How to Build With Glass Blocks

Glass Blocks are not a new product, but they are now very much back in vogue. Traditionally these have been used to create partitions and shower cubicles or to fill in where windows have been.

However, there is no reason that they cannot be used to create table features or an attractive feature outside. By the use of the addition of artificial light, whether coloured or normal these blocks can be transformed into a stylish addition to a room.

There are, however, rules that must be followed when working with glass blocks and the following information is designed to ensure that your features are both safe and good looking.


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    Do not use glass blocks to build load-bearing walls. A glass block wall with other construction on top must have a suitable and correctly supported lintel above it.
    • Glass blocks should always be built within a frame so that edges are protected and made neat.You cannot cut the blocks so the framing, ideally timber, must be built to suit the size of the feature. The blocks are 190 x 190 x 80mm and the spacing between each block is 10mm approximately.
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  2. 2
    Allow for expansion. When the blocks are to be used in an area affected by temperature changes, for example as a shower enclosure side or a panel alongside the front door, you must allow for the expansion and contraction of the glass. The normal white mortar used to bond the blocks must not be used around the perimeter of the feature against the framing.
    • You must use Wickes Expansion Foam to infill the gap between the glass and frame. Coat this with white silicone for a neat sealed finish.
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    • If the area of the feature exceeds two square metres or if the glass blocks are being used as a shower enclosure wall or as exterior door side panels which could be broken away by an intruder you must add reinforcing. As you build, bed Wickes Stainless Steel Reinforcing Rods into the mortar between blocks in every third row both horizontally and vertically. Horizontally lay the rods, staggered in pairs, in the mortar with each pair overlapping the next by at least 150mm for continuous strength. Diagram B. The ends of the rods, which reach the framing or sidewalls should be inserted into 15mm deep holes drilled into the framing or walls. Make the holes as the walling is built up to ensure alignment. Vertically simply insert the rods into the mortar as the blocks are built up.
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    • The use of the reinforcing rods will add considerably to the strength of the construction.
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    Always use the spacers to maintain the alignment of the blocks. Not only do they ensure alignment, but also prevent the weight of the blocks compressing the mortar before it cures. spacers are not visible when the wall is complete. Chart A gives a guide of how many you will need. Wickes White Mortar be mixed to a stiff consistency for best adhesion to the glass, which is non-absorbent. Fill the voids and remove excess mortar squeezed out of joints with a clean damp cloth as the work proceeds. Diagram E. Each 12.5kg bag of white mortar is sufficient for between 20 and 25 blocks approximately.


  • When building walls, care should be taken when positioning blocks. In certain conditions, masking on the outer edge can be visible. The 'bar code' should be positioned out of the line of sight.
  • Corner Blocks can also be used, but must have stainless steel rods built.

Things You'll Need

  • Glass Blocks
  • Glass Block Single
  • Glass Block Corner Single
  • Spacers
  • Mortar
  • Reinforcing Rods
  • Expansion Foam

Article Info

Categories: Home Improvements and Repairs | Build Design & Remodel Own Home