If you have a commercial building insurance policy in force, the premium and cover will be based on a number of factors. One of these is the type of occupancy. As you can imagine, a building that is occupied as a fish and chip shop or woodworker is going to present a higher risk of fire loss than an office.
Insurers will either charge a higher premium, to reflect the increased risk, or apply terms (such as having all dirt and grease removed from takeaway ducting every month).
When a tenant leaves a property there is usually going to be a gap between when one business is trading and the next one starts. This can either be whilst you are awaiting new tenants or whilst there is a shop re-fit undertaken. You could be faced with months and months when the building is empty, given the tough economic times. There are estimates that 15% of the existing Woolworths store premises are still empty, nearly two years after the companies demise.
Your policy wording, as with all business insurance, will have certain terms, conditions and excesses. One of the conditions will relate to what happens to the cover when a building is empty for 30 days or more. Usually, if aa building is empty, un-tenanted or vacant for more than a month, there are fairly onerous cover restrictions.
You will find that your glass, storm, burst pipes or theft cover is excluded. The reason is that insurers, from experience, suffer more losses on unoccupied properties than they do tenanted ones.
You need to check your policy wording to see what terms apply if your building is going to be empty for any length of time.