As I’ve mentioned before, my buildings are made from Daler board (2mm thick artists mounting board available from Art shops) covered with plasticard. The card is lovely and easy to work as well as being very cheap – five quids worth will be more than enough for two layouts this size.
My glue of choice for attaching bits of card to each other is Alphatic resin, a posh PVA used by the aeromodelling community. It sticks well and grabs quickly. This is handy when you screw up. I marked one of the windows too low and had to re-instate the rectangle I cut out. That won’t be a problem assuming the building progresses beyond mock-up stage. The plastic will hide it from view. However I’m quite pleased, a clean cut with a sharp scalpel and some good glue and it’s nearly as good as new. Perhaps I should have been a surgeon.