When should you not use expanding foam?

You should not use expanding foam in situations where it can cause damage, create safety hazards, or is not appropriate material. Do not use expanding foam around windows and doors that require low expansion foam, as high expansion foam can bow frames and prevent operation, use low expansion window and door foam instead. Do not use expanding foam in areas exposed to direct sunlight without covering, as UV degrades foam. Do not use expanding foam as only support for heavy objects or structural support, as it is not structural. Do not use expanding foam near open flames, sparks, or high heat sources before cured, as it is flammable during application. Do not use expanding foam in electrical boxes where it can interfere with wiring and cause overheating, use fire rated caulk instead. Do not use expanding foam to fill large voids over 3 inches deep in one application, as it may not cure properly inside, apply in layers. Do not use expanding foam on surfaces that need future access like plumbing cleanouts. Do not use foam where water drainage is needed, as it can trap water.