Arson is the deliberate use of fire or explosives with the intention of damaging or destroying real property or personal property. It is a crime in most jurisdictions, as well as giving rise to a private action (a tort in common law jurisdictions) against the perpetrator.
Damage from arson by a beneficiary (as opposed to a disinterested third party) is a common exclusion in most insurance policies that cover damage from fire. However, an insurance company denying coverage for arson without sufficient evidence is generally held to be acting in bad faith and may be subject to punitive damages in addition to the damage done in the fire. See, for example, Whiten v. Pilot Insurance Company  1 S.C.R. 595