Problem
Any homogenous membrane which has holes in it will tend to rupture at the holes, unless the edges of the holes are reinforced by thickening.
Solution
Do not consider door and window frames as separate rigid structures which are inserted into holes in walls. Think of them instead as thickenings of the very fabric of the wall itself, made to protect the wall against the concentrations of stress which develop around openings. In line with this conception, build the frames as thickenings of the wall material, continuous with the wall itself, made of the same materials, and poured, or built up, in a manner which is continuous with the structure of the wall.
Related Patterns
… assume that columns and beams are in and that you have marked the exact positions of the doors and windows with string or pencil marks - Natural Doors and Windows (221). You are ready to build the frames. Remember that a well made frame needs to be continuous with the surrounding wall, so that it helps the building structurally - Efficient Structure (206), Gradual Stiffening (208).
In windows, splay the thickening, to create Deep Reveals (223); the form of doors and windows which will fill the frame, is given by the later patterns - Windows Which Open Wide (236), Solid Doors with Glass (237), Small Panes (239) …
Reference for full-text of Pattern: p. 1059high-confidence