The final mosaic is quite large (192 x 256 studs -- 60" x 80"). It consists of about 12,000 pieces and weighs probably about 40 pounds or so. It is built 'studs out' so that there are baseplates behind it holding it all together, and as one faces, it the studs of the bricks are pointed outward toward the viewer.
It took only a couple of weeks to build.
The real task was hanging the mosaic (the difficulty was compounded by the fact that I was hanging onto a wall that was made of stone). My father and I accomplished the hanging of the 'LEGO tapestry' in about two and a half hours. And, believe it or not, absolutely no glue was used... the bricks seem to be holding themselves together.