To be more specific I am referring to fireblocking. The definition for fireblocking given by the International Residential Code is as follows: building materials or materials approved for use as fireblocking, (yes, the IRC uses the word in the definition- circular definition!), installed to resist the free passage of flame to other areas of the building through concealed spaces. As you dig deeper into the IRC specifically Section R302.11 Fireblocking will give a more in-depth answer in regards to this important fire safety requirement. Typically you see the fireblocking between floors, soffits, between stair stringers and floor penetrations for pipes, ducts etc. Materials allowed to stop the free passage do not need to be fireproof! Some examples are two-inch nominal lumber, one half inch gypsum wallboard (not required to be fire coded), batts of fiberglass insulation and several other materials are permitted.
Fireblocking is essentially starving a fire of oxygen and prevents it from spreading and is not a recent addition to the building codes. There are references dating back to the 1905 National Building Code at that time it was referred to as a fire stop (I am going to guess it was defined as something that stopped the fire, but these were the days before codes had a definition section). It was not until the 1990’s when the term fireblocking became the proper terminology.
I have seen many people decide to finish their basements without seeking an architect’s advice which is an acceptable approach however, some of these people bypass getting a building permit as well. This is a definite no-no! When you take the proper route your local building official comes out and does inspections to make sure you are conforming to the construction codes and keeps you safe in your home. If you have some handyman or perhaps you even personally finish the basement you may have missed some key components to the International Residential Code one of them being fireblocking! It doesn’t take much for fire to spread quickly throughout your house if you do not construct your walls soffits and stairs correctly. It can take 30 seconds to a minute for a fire to engulf your entire home! I have seen General Contractors that even ignore drawings showing the proper detail for fireblocking. Sometimes they will pop in half-inch plywood or some other material they have handy and call it a day. Guess what, this is not an approved method and your building official will catch it almost every time and have the contractor remediate and do it properly.
So if you plan on doing some home projects on your own seek some professional advice and save yourself some headaches and sleep soundly at night knowing you did the right thing in protecting your loved ones! Give your local architect a call or set up a meeting with the local building department and see what you need to do to complete your vision.