The window is a weak point in the envelope of the building and must therefore be considered very carefully during the design phase keeping in mind the following needs:
- Air / water / wind seal
- Limited effect of the thermal bridge and surface temperatures
The aesthetic / architectural needs must naturally be added to the previous 3!
As far as the air / water / wind seal is concerned, the market offers many different products able to meet different needs and solve problems. Examples include: butyl tapes, acrylic tapes, expanding tapes, permanent elastic foams, membranes, etc …
The air / water / wind seal is important as it allows to avoid air leackages and unwanted energy losses and therefore to contain winter and summer consumption. But as it is well known, wood must be kept dry and it is therefore necessary to prevent water from entering in contact with the structural parts. For a more exhaustive discussion, see the specific articles on airtightness and BlowerDoor.
A correct design must also ensure that the node is resistant to the wind and in this regard it should be remembered that the wind load can easily exceed 50kg / sqm. This means that for a window the total force in the event of wind can be more than 100kg.
Il carico vento va calcolato in accordo alla normativa italiana NTC08.
The surface temperatures and the value of the linear thermal bridge must be evaluated using special finite element calculation software (FEM). Ergodomus uses MoldSimulator and is at your disposal for FEM analysis not only related to window and door frames. Contact Us!
Le immagini seguenti sono stratte dal libro “Legno… Costruire… Abitare” scritto dall’ing. Franco Piva alcuni anni fa ma che presenta concetti sempre attuali.
The objectives described above can be easily achieved only if the details are defined by the designers.