accession of property

In English and Scottish law, any addition to property either natural (for example, the offspring of livestock) or artificial (for example, a new building), belonging to the owner of the nuclear property and said to be acquired by accession.

In Roman law, property acquired artificially, as, for example when someone builds a house on another's land or embellishes or works on another's material, was held to be the property of the owner of the principal thing, provided compensation was made for improvement. An exception was made in cases where, as the result of labour, a totally new thing was produced. Thus the person who made wine from another's grapes, or painted a picture on another's canvas, retained the wine and the picture, and compensated the owners of the grapes and the canvas.

In the USA all accession or accretion is, in the absence of any agreement to the contrary, the property of the owner of the principal materials.