Conditions under which the interface of a rotating layered model can surface and form geostrophic fronts are investigated. It is shown how a simple one-dimensional, reduced-gravity model, despite its oversimplicity, can lead to surfacing criteria and upper bounds on the extent of the ventilation area created by the separation of two newly formed fronts. First a no-surfacing theorem is established under restrictive conditions. Then, by relaxing conditions one by one, wind coast, and topography effects are investigated and front properties derived. The present search for frontogenetical criteria and ventilation upper bounds which per se is a novel approach to frontal studies is aimed at complementing the existing frontal stability studies by offering additional information on front properties. Extension to multilayered and two-dimensional models is briefly anticipated, calling for additional work before more general criteria can be formulated.