3) Any single storey extension of a dwelling the total floor area of which exceeds 25m2 including means of access and any external works in connection with that extension.
3) Unrhyw estyniad un llawr i eiddo sy'n fwy na 25m2 o ran arwynebedd llawr, gan gynnwys dull mynediad ac unrhyw waith allanol ynghlwm wrth yr estyniad hwnnw.