Mass. Gen. Laws ch. 241 § 23
If the court in which partition proceedings are pending finds that one of the co-tenants has erected any buildings or made other permanent improvements on the common land, it may, if justice and equity so require, award such compensation as it deems proper for the value of such buildings or other improvements, not exceeding, however, the actual amount by which the market value of the common land has been increased thereby; and in awarding such compensation the court may deduct any benefit which the party claiming compensation has received from the common land. The court may make orders and decrees for the enforcement or protection of any such claim, and in case of partition by division may order the improved part set off to the party who made the improvement, and the land divided as if the improvement had not been made.
Mass. Gen. Laws ch. 241, § 23