Updated: 10.11.2026
The Glazing build-up describes which panes a glazing unit consists of. The designation 4-16-4 means: 4 mm glass, 16 mm cavity, 4 mm glass. For a window actuator only the sum of the glass thicknesses counts, because it determines the Sash weight.
Glass weight per square metre
Glass weighs about 2.5 kg per square metre and millimetre of thickness. The cavity weighs practically nothing. The table shows the pure glass weight; frame and hardware come on top.
| Glazing build-up | Total glass thickness | Glass weight per m² | Typical use |
|---|---|---|---|
| 4 mm single glazing | 4 mm | approx. 10 kg | Old buildings, greenhouses |
| 4-16-4 | 8 mm | approx. 20 kg | Double glazing, standard |
| 6-16-6 | 12 mm | ca. 30 kg | Large sashes, roof windows |
| 4-14-4-14-4 | 12 mm | ca. 30 kg | Triple glazing, new builds |
| 44.2 laminated-16-4 | ca. 12,8 mm | ca. 31 kg | Safety glass inside, overhead glazing |
| 8-16-8 | 16 mm | approx. 40 kg | Very large sashes |
| 6-12-6-12-6 | 18 mm | ca. 45 kg | Triple glazing, large areas |
How to read the designations
- 4-16-4: Double glazing, two 4 mm panes with 16 mm spacing
- 4-14-4-14-4: Triple glazing, three 4 mm panes
- 44.2 laminated: Laminated safety glass made of two 4 mm panes with two 0.38 mm interlayers
- Toughened glass: Toughened safety glass, weighs the same as normal glass of the same thickness
Example
A sash of 1.2 × 0.8 m = 0.96 m² with triple glazing 4-14-4-14-4 has about 0.96 × 30 kg = 29 kg of glass. With frame and hardware it is a good 32 to 40 kg depending on the profile.
Glazing build-up in the calculator
In Window actuator calculator you select the glazing build-up from the list. The glass thickness is entered automatically, and the weight and required thrust are calculated immediately.
Frequently asked questions
Where can I find the glazing build-up of my window?
It is often stamped on the spacer between the panes, for example “4/16/4”. Otherwise it is in the window manufacturer’s documents.
Does the gas filling change the weight?
No. Argon or krypton in the cavity weighs only a few grams and is irrelevant for the actuator.
Read more
See also in the glossary: Overhead glazing
Not sure which actuator fits? Call us at 040 50694631 (Mon–Fri 8 am–5 pm) or use the actuator finder.
Related terms: Laminated safety glass (VSG)
