To safeguard your investment of quite a few thousand pounds your conservatory requires a sound base to sit upon, the footing is a deep trench filled with concrete, and sometimes steel cages, around the perimeter of the conservatory, to support the wall and the weight of the conservatory. It's called a footing because it is usually about a foot wide- and they are usually at least two feet deep. Depending on the ground conditions footings may have to go down a metre or more.