You should use extreme caution when using any heat source on your new deck or screen porch. When grilling or using a patio heater, for example. Grills and patio heaters can reach temperatures over 800 degrees and can cause severe damage to structures, so keep plenty of distance from railings, houses, or anything else that might come into contact with the heating element. If you're installing a heat source near an existing structure, read the manufacturer's instructions. Whenever you use a heat source, make sure it's always maintained properly and never left unattended. It's very easy for grease to catch on fire.