When planning a full basement project from bare concrete floor and walls to fully finished, the layout is first designed to meet all the desired rooms, typically the main rec-room area, a bathroom, laundry, furnace room, and one or more bedrooms are usually included as well. Beyond plotting the walls, entryways to each room, and a few necessary closets, working around ceiling protrusions can be the most daunting tasks of all.
Unlike the modern lower-level walk-out that often boasts ceiling heights of eight to nine feet (or more), older homes were built with lower basement ceilings in mind. As such, it is necessary to factor in the lower wall elevations when choosing the type of ceiling to use. Additionally, there are often conduits for plumbing and/or central vacuum systems that are often mounted to the underside of the main floor joists, which further minimize wall height potential. Therefore, a suspended ceiling is frequently chosen in a basement setting, as the removable panels also provide on-going access to various electrical, plumbing, and other household services that run through the main floor joisting in the home. However, one specific basement feature tends to disrupt a well-intended framing plan ducting.
Unlike smaller conduit that affects the ceiling height by only an inch or two, a main feeder duct hung below the main floor joists can drop by eight to 10 inches (or more). As such, and because it would be impractical to use this as the lowest common denominator for an entire space, the ceiling must then be broken up into sections, divided by box-framing around the main ducts. Most times, the main ducts that feed venting throughout the house run adjacent to a main support beam, which can be encased within the same box-frame. No matter, sole beams must also be enclosed within a separate frame. Ceiling box-framing does complicate the process, but it is imperative to accurately plan the manner in which a basement ceiling will be tackled to ensure the desired result.
Before starting to frame, establish whether the walls will be mounted directly to the concrete, or added subfloor. Basements that tend to incur minor leaks or trickles now and again would benefit from a subfloor panel with air gap technology to segregate the moisture from the living space. In this instance, the walls can be framed directly to the topside of the subfloor surface. Keep in mind that subfloor panels do decrease the overall wall heights by roughly an inch or so, and thats before factoring in the type of finished flooring as well. When building direct to concrete, I prefer to pre-map a 2x4 base of the wall design using treated lumber fastened directly to the concrete floor, upon which the walls built a quarter-inch shorter are first mounted the above joists, and secured to the treated base providing the pre-established quarter-inch gap. In the event water finds its way on to the concrete floor, the treated lumber will shoulder the effects of moisture while allowing the main wall framing to remain dry and undamaged.
Once the exterior walls are framed, and the interior walls are in place designating the various rooms based on the plan, the box framing is usually the final step. To maximize height below a box-frame around a main duct, it is best to focus on hanging the lower horizontal sections at roughly the same elevation as the underside of the lowest portion of the ducting. By doing this, the finishing surface (most often drywall) will be at its highest potential. Framing around the entire duct will only decrease the height below the box-frame. In some instances, faux box-framing is added along the entire perimeter of a room for aesthetic reasons, or to include perimeter lighting these are design choices beyond the minimum box-frame requirements.
Once the box-framing around all ducting and other protrusions is completed, the electrical, rough plumbing, and additional ventilation components are introduced. The insulation and vapour barrier is then installed along the exterior walls, and all wall and box-framed surfaces receive drywall. All drywalled surfaces are then mudded, beaded, sanded, primed and painted, before the isolated suspended ceiling grid sections are installed. Careful box-frame planning is sure to pay off.
On occasion, a homeowner may prefer drywall along the basement ceiling, despite minimizing or completely eliminating access to any or all services (unless access panels are strewn throughout, which may defeat the purpose). That is why suspended ceilings in a basement setting is the popular choice. And although basement ceilings can be challenging, there are always multiple ways to approach any basement ceiling project. When the design is well-conceived, an eye-sore before completion can evolve into a beautiful focal point its all in the manner of approach, that best suits the design layout.