First things first: calculate the wall opening

Before anything, you will need to calculate the wall opening for your Rods & Mortar kit. To calculate the wall opening area, take the following steps:

1. Take the width of the block (190mm) and mutliply by the number of blocks you need (in this example we use 6 blocks): 190mm x 6 = 1140mm
2. Multiply the width of the spacer joint (10mm) by the number of blocks (6), and add it to the above number: 10mm x 6 = 60mm
3. Add one more end joint (10mm) to close off the wall
4. 4. The total comes to: (190mm x 6) + (10mm x 6) + 10mm = 1210mm

Note: The Rods & Mortar Kit page will automatically calculate the correct opening size for you based on your selections.

Install Panel Anchors
The glass block panel is tied into the frame by use of panel anchors (these become embedded in mortar). Anchors are attached to jambs and head but not the cill. Anchors are usually placed at 400 mm centres.

Install Expansion Strips
Expansion strips should be stapled or nailed along jamb and head between anchors (no strip necessary to cill).

Preparing Glass Block Spacers
The standard spacer is actually three spacers in one. By simple trimming of certain elements, 'L' and 'T' spacers are also created.

Position Spacer Correctly
Normally, the spacer crossbar should face downward. The crossbar should only face upwards at the cill as a 'T' spacer.

Prepare the Mortar
A 15 kg bag of pre-mixed glass block mortar is sufficient for installing approximately 13 No. 190 x 190 x 80 mm blocks. Follow the instructions on the bag.

GOLDEN RULE - NEVER DRILL OR CUT GLASS BLOCKS!

LAYING THE FIRST COURSE

1. Apply glass block mortar to clean level cill. Use enough mortar so that a 10 mm joint will remain when blocks are in place.
2. Using the 'L' and 'T' spacers on the cill and jamb surfaces, insert first at lower corner.
3. Push the block snugly into place ensuring it is properly seated. Place a regular spacer on upper corner of the first block. Apply layer of mortar to the vertical edge of the new block and put into place. Once again, check the block is properly seated.
4. Continue laying first course by repeating steps 1, 2 and 3. Periodically, use level and plumb line to ensure accuracy of panel. Adjust as necessary before continuing.

INSTALLING THE REMAINING COURSES

5. When first course is completed, apply layer of mortar to top block spread and smooth making sure that crosslegs of spacers are free of mortar. This ensures accurate spacing.
6. Continue laying blocks repeating steps 1-5.
7. When you encounter panel anchors, ensure that the top of the block (with spacer in place) slips under the anchor. Continue finishing that course then apply mortar to top, embedding anchor.
8. For panels with spans of more than 1.4 m, panel reinforcing must be used on top of every horizontal course for 190 x 190 x 80 mm blocks. Once mortar has been placed on top course, simply press stripe of reinforcing into mortar. If you use more than one strip, an overlap of 150 mm is required.
9. When laying top course, put appropriate spacers in place before inserting block.

FINISHING AND CLEAN UP

1. Using a sponge or damp cloth, remove excess mortar from face of glass blocks (both sides). Be sure to rinse often using water only (no abrasive products). Do not let mortar dry completely before removal from block. Block will be left with a light film of mortar dust which can be removed later using a dry cloth.
2. Twist end tabs off all spacers after mortar has set for one hour. Use striking tool for joints. This produces professional results and compacts the mortar to create a moisture resistant seal. After striking, all joints should be left full of mortar (for shower joints, you may rake the joints to a depth of 5 mm and then after 24 hour cure, fill the joints with a wide joint panel grout. After two hours, wipe blocks with soft, clean cloth).

3. One or two hours after striking joints, wipe the block faces with a soft, clean cloth.
4. Using a caulk gun, apply silicone continuously along the seams where the block panels join the jambs and the head. Be sure to apply sealant on both sides of the panel. Trim may also be applied at the seams. If you have a wooden curb cover it with a suitable moulding.

These instructions are for guidance only. They are not intended to imply suitability for any purpose. Glass block panels are not load bearing. The Rods & Mortar System is suitable for fire rated walls if removable spacers, a fire rated compression strip and fire rated silicone are used.