Question: Why is a firewall or a separation wall required between an attached garage and the rest of my home?
Answer: The purpose of this separation is to slow down the spread of a fire if it were to start in the garage. Many people store in their garage flammable and other items which are more likely to start an accidental fire. Thus, for your family’s protection, a separation wall would provide those extra minutes you would need to vacate your home if a fire were to start in your garage.
Usually there must be fire-rated drywall from the floor to the roof as a separation on any walls between the garage and living spaces. The door into the house must be steel or solid wood or have a 20 minute fire rating. Some municipalities may require you to add self-closing hinges to this door. If the ceiling of the garage is hung with 5/8” fire-rated drywall then the sidewall drywall only needs to be hung to the ceiling. If there is a penetration of the drywall ceiling with a disappearing stairway you can buy special units which have the fire rating. The garage cannot have any heat or cold air runs from the home’s forced air heating system. Any penetrations of the wall should be caulked and sealed with a fireproof material. It’s always better to be safe so if you have an older house which doesn’t meet these precautions you might want to consider adding these features to your home.