Iowa Code § 563.9: Paying for share of adjoining wall.

Every proprietor joining a wall has the right of making it a wall in common, in whole or in part, by repaying to the owner thereof one-half of its value, or one-half of the part which the proprietor wishes to hold in common, and one-half of the value of the ground on which it is built, if the person who has built it has laid the foundation entirely upon the person’s own ground.