Definitely interesting to build a house of roofing tiles!
I forgot to mention that this appartment was the first time I saw aluminum wiring in Austria. Single, pvc sheathed 1 sq. mm wires directly buried in plaster, found in the bathroom, above the sink!
I guess the wiring dates from the 1950ies, because there was no PVC sheathing prior to this. It can't have been installed after 1962 because then the bathroom was completely remodeled and rewired (About the most solid part of the installation, even with red ground wires everywhere (not the old ladie's fault that the water supply line it was connected to was later replaced with plastic), though it involved the bad connection I mentioned earlier.
