We´ve all seen that certain type of creativity when it comes to potential solutions to support doors & windows, mostly generated by installers.
Timber is not the greatest idea for supporting doors & windows in external wall insulation layers. Beside the fact that the load bearing isn´t certified, there´s always a high risk of rot.
Steel brackets do definitely carry the weight of doors and windows but have to be manufactured bespoke. Also, they can create a serious thermal bridging.
The common strategy of filling the space underneath the threshold with concrete, once the door is installed, will lead to problems with thermal bridging and moisture transfer.
Installing windows and doors has to become more challenging over the last decade due to permanently increasing insulation requirements and heavier windows and doors, caused by triple glazing.
The growing demand for large-sized sliding doors and floor-to-ceiling windows in new builds, as well as new insulation methods like external wall insulation, is putting pressure to architects, builders and window suppliers regarding practical solutions for supporting windows and doors.
The most previous attempts for supporting windows and doors were not practical for the following reasons: