As my wife is a dolls house collector, I've been roped into helping make the houses and do the electrics etc. Most traditional dolls houses are 1 :12 scale therefore no good for G scale, but there appears to be a smaller scale which is becoming more and more popular 1 : 24 !!!
Found a couple of suppliers on the net and they appear to be a good source of ready made wood and plastic ready made windows and doors.
http://www.eshop-systems.net/mollys_house/Plastic+Windows+and+Doors+PUVqTndBVE02a25jdmRXWjBGMlk
Just had some of the plastic victorian windows and doors back and they seem ok so far.

Found a couple of suppliers on the net and they appear to be a good source of ready made wood and plastic ready made windows and doors.
http://www.eshop-systems.net/mollys_house/Plastic+Windows+and+Doors+PUVqTndBVE02a25jdmRXWjBGMlk
Just had some of the plastic victorian windows and doors back and they seem ok so far.
