Conn. Gen. Stat. § 47-230: Alterations of units.

Subject to the provisions of the declaration and other provisions of law, a unit owner:

(1) May make any improvements or alterations to his unit that do not impair the structural integrity or mechanical systems or lessen the support of any portion of the common interest community;

(2) May not change the appearance of the common elements, or the exterior appearance of a unit or any other portion of the common interest community, without permission of the association;

(3) After acquiring an adjoining unit or an adjoining part of an adjoining unit, may remove or alter any intervening partition or create apertures therein, even if the partition in whole or in part is a common element, if those acts do not impair the structural integrity or mechanical systems or lessen the support of any portion of the common interest community. Removal of partitions or creation of apertures under this subsection is not an alteration of boundaries.