course#2 - Installation of Doors and Masonry


 Lesson two shows how to install door frames in a non-destructive way.  No metal parts whatsoever are fixed to the stone supports.Only modern organic 'glues' and natural lime are used to fix the frames.  The fixing principle is two-fold: firstly mechanical fixing and secondly adhesion.  Polyurethane foam shares both principles as the plastic mass shows high cohesion to the stone and the frames (if wetted beforehand) and strong mechanical force due to its expansion and hardening.  Polyurethane foam is UV sensitive however and must be protected by a layer of lime.  This layer adds both to the cohesion and to the mechanical force.

Doors are mainly mounted with polyurethane foam and lime, while windows are mounted with polyurethane foam and SIKA FC 115 adhesive.  No lime is used on the outside of windows and the polyurethane foam must be entirely covered by the SIKA adhesive.  With windows lime is used on the inside for decorative reasons and to UV protect the mounting.  This second technique requires close tolerances between the frames and the stones and this is the main reason why it is of little use for doorframes on old buildings.  You will notice from the pictures that the openings are very irregular and often not rectangular or vertical.