4) Any two storey extension of a dwelling the total floor area of which does not exceed 50m2, including means of access and any external works in connection with that extension.
4) Unrhyw estyniad deulawr i eiddo sy'n llai na 50m2 o ran arwynebedd llawr, gan gynnwys dull mynediad ac unrhyw waith allanol ynghlwm wrth yr estyniad hwnnw.