What Are the Advantages of a Drop Header?
A header is a horizontal structural member in a house or building. If you stand in a doorway and look directly up, the header is the framing member underneath the casework, and is supporting the ceiling. Obviously, the larger the span of the opening, the larger the header needs to be. For example, if you opened up the kitchen in an old house by removing a wall, you might replace it with a header. A drop header is one that is positioned directly below the joists above it, instead of being tucked into the joists so it is flush with the ceiling.
Drop headers are common in remodels. It's far easier to retrofit a drop header than it is to install one flush with the ceiling, because you don't know what the bays between the joists will be like; they may contain duct work, wiring or plumbing. The joists may be running the wrong direction. As a result, drop headers give homeowners and contractors a feasible way of better utilizing space, such as modernizing a kitchen, creating open living areas and remodeling basements.
Support Post Elimination
Drop headers are also common in basement remodels. On older homes, posts were often used as structural elements called point loads, where the weight of the structure above is concentrated on a single point, supported by the post. It's structurally functional, but if you want to reclaim the basement as fully usable living space, you don't want a post in the middle of the room. You can use a drop header to distribute the load: Install two posts on either side of the removed post, tucked into the wall framing. The drop header, properly sized to carry the load, spans the two posts, replacing the original post and distributing the weight to two different points. An engineer may have to calculate the type and size of header.
Basement remodels often have framed-in soffits used to dress up duct work for heating and ventilation. They are also used to hide plumbing and electrical systems. Basement remodels attempt to minimize the rerouting of infrastructure such as plumbing. However, if you are going to build a soffit to hide a drop header, you can take advantage of the space, using it to re-route necessary systems, such as plumbing, which would otherwise be exposed. That way, all systems are concealed along with your header.
Retrofitting headers flush with a ceiling is simply more expensive. You have to cut into the ceiling to make room for what is often referred to as a pocket beam because it is concealed in a pocket or joist bay. It's difficult to cut overhead, especially while ensuring every snag or nail-head won't keep the new beam from fitting. Installing the header bellow the joists is much easier and requires a lot less time.