Insurance companies do not require an appraisal to determine the value of a building for co-insurance. Instead, the policyholder decides how much coverage to purchase. Building owners may want to obtain a professional appraisal to determine the cost of rebuilding to ensure their coverage limits are adequate to meet the co-insurance requirement of their policy. It is generally in the policyholder's best interests to have an appraisal done to confirm the value of the building because it's the only way to rest assured that you do have adequate coverage in place and you will be able to receive the property value of your claim should you experience a loss. This is subject to all other terms of the policy and claim circumstances.
Your Morison Insurance broker has tools to calculate an approximate estimated value for your property, but it's crucial to keep in mind that it's only an approximate estimate. There may be factors at play that your broker doesn't know about and, therefore, can't account for. That's why it's much better to have a professional contractor evaluate the building and give you an estimate of its value based on how much it would cost to rebuild if it were destroyed.