Renovation & Design

Let your light shine down

Adding new lighting to a ceiling a bright idea

The wiring for new LED slims was introduced before the ceiling was taped and mudded.

Other than the bulkhead, the new lighting is introduced by feeding wiring within the joist cavities above a finished ceiling via temporary access points, later patched and painted.

The wiring is fed from one light hole to the next in a daisy chain fashion before connecting the wiring to each LED box.

When a homeowner expresses a desire to eliminate a stippled ceiling, strapping a new ceiling in lieu of scraping has been my preferred approach. This process easily allows the introduction of additional ceiling lighting within the space as the wiring can be pre-run before the new drywall is installed. However, it takes a while to complete. Adding new lighting along a finished ceiling can be achieved in less time but comes with its own set of challenges. Because the wiring must be run from one lighting location to the next within closed joist cavities, the process can feel somewhat haphazard.

Although the results appear the same, the process of adding new slim LED ceiling lighting along a finished ceiling it technically achieved in the reverse order. Unlike a strapped ceiling, whereby the newly strapped cross supports are visible (allowing the systematic placement of the wire feeds), finished ceilings have closed off the joist cavities above. It then becomes necessary to locate and subsequently mark the positions of every joist before setting the new LED lighting design placement. Generally, joists above are set at 16-inch centres, and at 24 inches if the framework above consists of roof trusses. By locating the first joist, the others can be found by measuring back in increments of 16 inches (or 24 inches for trusses). On occasion however, joists and trusses are placed at shorter intervals depending on the structural design of the house. As such, this prep process can be quite tedious.

Once the joists have been located, the lighting design is configured. At a recent job site, the dining room would receive 10 new LED slims. Based on the joist placement, two rows of five LEDs, roughly 30 inches from the walls with a 70-inch gap between rows and 44 inches between lights along each row would accommodate the existing joists within the ceiling above. After confirming the accuracy of the LED locations marked along the ceiling, a four-and-a-quarter inch hole saw was used to create openings along the ceiling. This size hole is required for the four-inch LED slims chosen for this project.

With the holes in place, the feed wire (with the breaker to the circuit turned off) was run to the first hole. From there, a wire was then fed through the joist cavity to the lighting hole of the opposing row. Wires were also fed from all other light holes to the neighbouring hole at the other end of each respective joist cavity. The next step required a 54-inch long, three-quarter-inch auger bit — wires must now be fed perpendicularly through the hidden joists in the ceiling. By flexing the auger bit at one hole, and holding the drill close to the ceiling, the bit provides a near straight line (in theory) to the next lighting hole, which was in this instance roughly 44 inches away. Based on the 16-inch centres of the joists, every perpendicular wire feed must pass through either two or three joists. Other than a few anomalies whereby joists were doubled, or set closer together, the drill bit did manage to breach through the joists successfully until it became visible at the target hole. Once the drill bit appeared at the other hole, a wire was attached to the bit via a small hole through which the copper ground can be fastened, allowing the wire to be pulled back through the recently created drill path. However, not all attempts were successful on the first try, nor warranted. Whenever the drill bit was unable to create the proper path, or there lingered a fear that existing wires or ducts may impede the potential for drilling a successful path, supplemental access points midway between two light holes were required to fish the wiring through to the next hole. As such, additional access points were created in many instances throughout this ceiling — it became soon evident that the joist placement, and existing wiring locations for that matter, were just too unpredictable.

Once all light holes were wire-fed one to the next (in a daisy-chain fashion), all instances of newly fed wiring are connected to the respective boxes of each LED slim, with the first box connected to the line feed wire which terminates at the last light along the chain. A quick flip of the switch reveals all 10 lights along the series turn on, indicating a functioning circuit. The supplemental access points are then patched with drywall, mudded with a few coats, and then sanded. The entire ceiling is then repainted to conceal any of these minor and incidental repairs. While the ceiling was given a refresh, the entire space has for the first time an appropriate amount of lighting potential, controlled by a new dimmer switch.

Strapping a ceiling requires considerably more effort to introduce ceiling lighting throughout a space. However, every step is procedural. Conversely, the process of adding new lighting to a finished ceiling can be achieved in less time, provided things go “as planned”. Without X-ray vision, it’s often difficult to forecast what lies behind the ceiling drywall within each joist cavity. And although the long flex-bit saves time, blindly drilling through joists can be quite unnerving. Cutting additional access points that can be later patched is often the better tactic, even though it might lengthen the process. After all, it is a much safer approach, and safety should be the focus at any job site.


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