The owner shall provide a screen door for all doorways opening directly to the outside from any dwelling unit or rooming unit where the screen door will be permitted to slide to the side or open in an outward direction, provided, that in an owner-occupied unit, the owner need provide screens only for those doorways used for ventilation. All new or replacement screens in screen doors shall be of not less that 16 mesh per square inch.
Said screen door:
105 CMR, § 410.552