IF you can show that the fire was caused by your neighbor's negligence, or unreasonable carelessness (such as smoking in bed; leaving a pan full of oil unattended on the stove; DYI wiring/electrical work which was dangerous; etc.), then you could potentially sue the homeowner for your loss. However, if there was no fault, then the homeowner is not liable, or responsible--a person is only liable for damage which she causes through a wrongful act, such as being negligent or acting intentionally in a wrongful fashion (for example: deliberately burning her home down for insurance fraud).You cannot claim against her insurance; her insurance covers her, not you. The only way you can seek compensation is by suing her and winning, which means proving her fault in court.