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Window technology: Carpenters and carpenters provide expert advice and installation
Window technology: Carpenters and carpenters provide expert advice and installation
Video: Window technology: Carpenters and carpenters provide expert advice and installation
Video: How To Install A Window (New Construction) 2023, February

Like hardly any other construction product, a window should meet a multitude of requirements - here are the most important ones.

Load capacity

Windows are stressed by the weight of the frame and the glazing, wind loads and building movements, vibrations due to opening and closing and temperature changes. The frame changes its shape imperceptibly for the human eye, but is strong enough for possible structural damage - if you stretched the frame into the building, it would take damage due to the length changes of the profiles. That is why the frame is mounted in single-shell outer walls on support blocks. In multi-layered outer walls, the windows are usually in the insulation level, in this case the window is safely led into the substructure using brackets or angles. The window is fastened to the structure by mechanical means, but displacements, subsidence, and deflections from the structure must not be led into the window. The carpenter adjusts the position of the bearing blocks to the size of the forces and the bending stiffness of the frame, they should consist of durable material, be sufficiently load-bearing, firmly and immovably arranged - and not affect the seal. The joints between the wall and window are permanently elastic sealed with play, so the frame does not press against the structure or tear on it.

Strength and bending stiffness

The profile thickness and connection of the frame corners depend on the expected load - the architect or carpenter determines the required area moment of inertia - the measure indicates the resistance of a cross section to bending. It is required to calculate deformations on components. Wooden profiles are characterized by high mechanical strength, wooden windows can be made slim and elegant.


Wind presses vertically on the frame and glass, but balls or birds can hit them. These forces are dissipated into the structure by the fasteners - brackets or claws, frame dowels, anchors or brackets. They are dimensioned so that the window sits securely under load, even with a sash open at 90 degrees. DIN 4108 Part 7 and Energy Saving Ordinance EnEV prescribe the airtightness of windows. Windows are sealed on three levels:

• Level 1 is on the inside of the component in a temperature range in which no condensation occurs; it separates the indoor and outdoor climate airtight.

• Level 2 takes over thermal insulation and sound insulation. The requirements for thermal insulation result from DIN 4108 and the EnEV, sound insulation is regulated in DIN 4109.

• Level 3 acts as weather protection and prevents rainwater from entering from outside. If moisture or water penetrate behind this level, they should be discharged directly to the outside.


Nowhere should rain get into the window, not even in a hurricane, at high altitudes and on the weather side of the house - professional construction of windows and connection joints are resistant to driving rain.

heat protection

The loss components of the frame are taken into account in the new calculation method for the u-value of windows. Small-part windows achieve poorer values, for example the frame proportion of lattice windows is 60 percent. Compromise: continuous insulating glass with an internal or external grille. Wooden frames with a cork core can improve the energy balance as well as plastic bars instead of aluminum strips as the edge bond of the panes.


Noise reduces the quality of living and is harmful to health. DIN 4109 Sound insulation in building construction applies to the requirements for sound insulation - it is specified in six sound insulation classes. Windows of sound insulation class 1 must reduce sound by 27 dB, in sound insulation class 6 a reduction of 52 dB is required. A science in itself means which sound insulation class is necessary for a house. The calculation also takes correction values ​​into account depending, for example, on whether the noise from slow or fast traffic should be dampened. Window frames should be equipped with a double seal, then soundproof glass with a special pane structure ensures quiet in the house. In addition to the window, the installation determines the quality of the sound insulation, especially the airtightness of the connection joint. Higher demands require a second sealing level and complete filling of the connection joint with suitable material.


Windows are said to make burglary more difficult and function as an escape route in an emergency. Burglar-resistant glazing makes it difficult to break in and protects against perpetrators who want to destroy the glass within reach of window handles. Most long fingers, however, try to pry open the frame. In contrast, burglar-resistant fittings and locks secure.

Sun protection

If you let the sun run free, it heats up rooms behind large windows - pleasant in winter, undesirable in summer. The Energy Saving Ordinance prescribes summer heat protection for houses with 30 percent or more glazing - the effectiveness of sun protection can be recognized by its reduction factor. The smaller the value, the better the shading keeps heat away. The EnEV does not specify a fixed value, it depends on the calculation of the primary energy consumption.

Fire protection

If there is a fire, the window frames should remain stable for as long as possible and not release any highly toxic gases. Windows can also be used in walls with fire protection requirements if the window meets the fire protection requirements - there is special fire protection glazing.

In this post you read:

  • Wood is a good framework
  • Carpenters and carpenters provide professional advice and installation

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