What is a draftstop?

How to Fire block walls?

First, lets qualify the term "Fire Blocking" vs. "Draft Stopping" Fire blocking is a term commonly used to describe the blocking used at the mid span of a wood framed area to inhibit the advance of fire within a concealed space, thereby maintaining the structural integrity of the building during a fire. It is described in the building codes (IRC/IBC) as follows: FIREBLOCKING. Building materials installed to resist the free passage of flame to other areas of the building through concealed spaces. Fireblocking is seldom required in residential construction any more (there are some exceptions), however there is a process called "Draft Stopping" that is common in all wood framing and used extensively in residential construction. Fireblocking is most commonly seen in fire rated assemblies (walls, floors and ceilings). It should be made of noncombustible materials or a rated assembly that incorporates combustible materials (rated assemblies have been tested and are built to very strict standards). There are some applications that allow standard dimensional lumber (such as 2x4's) to be used. Check with your specifications or code requirements in your area for clarification. Most can be placed using standard forms of attachment, such as nails, screws or staples, and some require special attachment processes. If special attachment is required, it will usually be spelled out in the design specifications (see you plans and details or assembly specifications). Draft stopping is described in the building codes (IRC/IBC) as follows: DRAFTSTOP. A material, device or construction installed to restrict the movement of air within open spaces of concealed areas of building components such as crawl spaces, floor/ceiling assemblies, roof/ceiling assemblies and attics. Draft stopping is required to be located in areas where a transition from horizontal to vertical or vertical to horizontal occurs. It is also required in spaces over a prescribed volume or square footage to limit how much air is available to feed a fire. The intent is to starve the fire of oxygen before it can grow to a point that it can cause severe damage to the building or structure. As draft stopping is used to limit air and not stop fire it can be build of almost any material approved by the building codes. We commonly use sheet metal, wood framing members, insulation or expanding foam for draft stopping. In Conclusion, it would be wise to determine what you are doing and which process you are required to use. Then, call your local building inspectors office or design professional of record and get approval for the application. Hope this helps! Terry