What are glazing blocks for?
Glazing blocks transfer the weight of the pane into the frame and keep it at a distance from the rebate base. This ensures that the pane sits stress-free, the glass edge and edge seal are protected, and the glazing rebate remains ventilated. In opening sashes, correct blocking also prevents the sash from sagging and keeps it running smoothly.
Setting blocks and location blocks
- Setting blocks transfer the weight of the glazing to the frame.
- Location blocks keep the glass edge at a distance from the rebate base. In opening sashes, they can also take on a load-bearing function as the sash deforms.
Dimensions: length, width and thickness
- Length: 80 to 100 mm is usual. GV glazing blocks are 100 mm long.
- Width: approx. 2 mm wider than the thickness of the glazing unit, so that the pane is fully supported.
- Thickness: depends on the distance between the glass edge and the rebate base. Blocks can be combined if required.
- Distance from the corner: approx. 100 mm for standard window sizes, more for large-format glazing.
The exact arrangement depends on the opening type (fixed glazing, side-hung, bottom-hung, tilt-and-turn sashes, etc.). Technical Guideline No. 3 of the German glazing trade (TR 3, glazing unit blocking) and the specifications of the glass or system manufacturer are authoritative.
GV glazing blocks: colour code and formats
Here, too, the colour indicates the thickness, consistently across all formats:
| Thickness | Colour |
|---|---|
| 1 mm | white |
| 2 mm | blue |
| 3 mm | red |
| 4 mm | yellow |
| 5 mm | green |
| 6 mm | black |
| 8 mm | grey |
| 10 mm | brown |
| 15 mm | grey |
| Widths (at 100 mm length) | Thicknesses |
|---|---|
| 20 · 22 · 24 · 26 · 28 mm | 1 to 6 mm, 8 mm only at 24 mm width |
| 30 · 32 · 34 · 36 · 40 mm | 1 to 6 mm, 8 and 10 mm only at 40 mm width |
| 42 · 44 · 46 · 48 mm | 1 to 6 mm |
| 50 · 52 · 54 · 56 · 60 mm | 1 to 6 mm, 10 and 15 mm only at 60 mm width |
For the workshop and the installation vehicle, there are assortments with mixed thicknesses, e.g. 100 × 24 mm in 1 to 5 mm.
Frequently asked questions
How wide does a glazing block need to be?
Approx. 2 mm wider than the thickness of the glazing unit. GV glazing blocks are available in widths from 20 to 60 mm.
How far from the corner are the blocks placed?
Approx. 100 mm from the corner of the pane for standard window sizes, more for large-format glazing. Technical Guideline No. 3 (TR 3) and the manufacturer’s specifications are authoritative.
What do the colours of GV glazing blocks mean?
The colour indicates the thickness: white 1 mm, blue 2 mm, red 3 mm, yellow 4 mm, green 5 mm, black 6 mm, grey 8 mm, brown 10 mm.
How long are GV glazing blocks?
All GV glazing blocks are 100 mm long.
These notes are general guidance from practice. The applicable regulations, the specifications of the window or system manufacturers and the project-specific planning are authoritative.