The top two floors of the historic Bridge Inn in Newhaven will be converted into one bedroom flats, if a planning application is successful.
Harveys in Lewes applied to Lewes District Council for planning permission to make the alterations because the letting rooms were under used.
The ground floor will eventually reopen as a pub once the top floors have been finished.
Harveys chairman Hamish Elder said: “When we acquired The Bridge last year we were not fully prepared for the amount of work necessary.
“The entire top two floors require reconfiguration to comply with current regulations. There are significant structural issues and the property is not ‘weather tight’ during the winter months.
“These are the sort of issues to be expected when taking over an historic property.
“Once we have resolved the immediate problems of reconfiguring and protecting the accommodation.
“We shall turn our minds to the retail operation below. Harveys are determined to reinstate a traditional public house emphasizing the heritage of the building but this may be another few months.”
Harveys wants to alter the first floor layout to accommodate five flats and the second floor to accommodate a further flat.
The existing pitched roofs over this area are to be altered to include a section of flat roof to provide headroom.