Preheat oven to 180 degrees C and cut out the paper templates for the house.
Turn out the chilled dough onto a lightly floured surface. Divide into 6 portions, 2 slightly larger than the others. Roll out the 4 smaller pieces to 5mm thickness and approximately the size of the four house panels, cutting out windows and a front door as desired. Roll out remaining dough, and cut into two rectangular roof pieces. Use any remaining dough to cut out decorative shapes with biscuit cutters (ie Christmas trees, gingerbread men, animals, etc.). Transfer dough to baking trays lined with baking paper.
Bake gingerbread for 10 minutes or until crisp. Leave the gingerbread on the baking trays for a few minutes to set then transfer to wire racks. Allow to cool for several hours or overnight at room temperature.
To assemble the house:
In a large bowl, lightly whisk 2 egg whites. Gradually beat in approximately 1/3 of the icing sugar. The icing should be smooth and stand in firm peaks.
Spread or pipe a line of icing onto a wooden cutting board and press in one of the side walls so that it sticks firmly and stands upright. If necessary, use tins or jars to help support it. Take an end wall and ice both the side edges. Spread or pipe a line of icing on the board at a right angle to the first wall, and press the end wall into position. Repeat this process with the other two walls until they are all in position. Leave the walls to harden together for at least two hours before putting on the roof.
Spread or pipe a thick layer of icing on top of all the walls and fix the roof pieces in position; the roof should overlap the walls to make the eaves. Pipe or spread a little icing along the crest of the roof to hold the two pieces firmly together. Leave overnight to set firmly.
When ready to decorate, make the remaining icing. In a large bowl, lightly whisk 4 egg whites and mix in remaining icing sugar as before. Use this to make snow on the roof and to stick on various sweets for decoration. Finish with a fine dusting of sifted icing sugar for snow.