"In the present covenant it is clear that 'house' is not used as a synonym for building. The erection contemplated is a house as the main building with possible subsidiary buildings. Looking at the restrictions on the use of the buildings I think that an ordinary layman would conclude that by 'house' in this covenant was meant a dwelling house. The primary meaning of the word 'house' I take to be a dwelling house for a family and the use of the word to describe office buildings such as the familiar Challis House or Wingello House in Sydney is a secondary use of that word. In my opinion the question whether a building occupied as several residential flats can or cannot be properly described as one dwelling house depends upon the nature of its construction. Two semi-detached houses side by side even though under one roof cannot in my opinion be regarded as one dwelling house within the meaning of such a covenant. I agree with Swinfen Eady, J., that it is impossible to differentiate the case of one house superimposed upon another and the case of two houses laterally adjacent to one another. When there is no common front door or staircase, no internal communication, when the residential units are structurally separate in every respect, they must, in my opinion be regarded as separate dwelling houses within the meaning of a simple covenant such as the present. On the other side of the line would be the not uncommon case of an ordinary two story dwelling house let as two flats, one lessee having the ground floor and the other the staircase and the upper floor, and both using the same entrance hall. Such a building is built as one dwelling house and one dwelling house it remains for the purpose of a covenant not to build more than one dwelling house. The border line case is where a house is erected with a common front door opening on to the street, common entrance hall and staircase leading to various self contained flats each closed by one door of its own. It may be that in the absence of any controlling context such a building would not be offensive to a covenant only to erect one dwelling house."