Windows and doors — requirements CE marking and Building Regulations

When a machine woodworker manufactures windows and external doors, the job is not finished when the piece is assembled and painted. The training regulations for machine woodworkers require that you can plan, document and perform ordinary machine operations in a production of windows and doors in accordance with the Building Regulations (goal 23 in the training regulations), and later independently document that the job meets applicable legal requirements (goals 35 and 39).

Since February 1, 2010, windows and external doors must be CE marked according to product standard DS/EN 14351-1, according to the Window Industry and Glass Facts. CE marking is not a quality guarantee in itself, but a common, documented measurement of properties such as energy performance, air tightness and water tightness, so windows from different manufacturers can be compared on the same basis.

• 01Type testing — the declared properties are established by testing
• 02A quality management system in production (factory self-monitoring)
• 03A performance statement (DoP — Declaration of Performance)
• 04The CE mark is placed visibly on the finished product

Beyond CE marking, the Building Regulations (BR18) set Danish energy requirements for windows installed in new construction. According to Glasfakta and the industry's own guidelines, windows today should in principle meet energy class A, which corresponds to an energy contribution (Eref) of 0 kWh per m² per year or more — that is, the window as a whole must provide at least as much energy to the house as it loses over a heating season. The requirements have been tightened several times since BR18 was introduced, and the joiner must therefore stay updated on what requirements apply to the specific task.

The U-value indicates how much heat one square metre of window or door loses per degree temperature difference, measured in W/m²K — the lower the figure, the better the construction insulates. In the heat loss framework for new construction, windows can either be calculated using their actual U-value or with a standard value set by the Building Code for the calculation, making it easier to compare different solutions early in a building project.

For a machine carpenter in window and door production documentation is not administrative chores alongside the craft — it is part of it. A window that looks nice but lacks correct CE marking or does not meet the energy requirements it is sold to meet cannot legally be built into a new building no matter how well it is assembled.

“A window must look right, fit right, and be able to document that it does what the paperwork promises.”