No unit owner shall undertake any work which would jeopardize the soundness or safety of the property, reduce the value or impair an easement or hereditament without the unanimous consent of all the other unit owners. Structural alterations shall not be made by a unit owner to the building or in the water, gas or steam pipes, electric conduits, plumbing or other fixtures connected therewith; nor shall a unit owner remove any additions, improvements or fixtures from the building without the written consent of the board of directors.