Drywall is one of the most popular materials used for constructing ceilings and, over the years, thousands of ceiling fans have been installed into drywall ceilings. Ceiling fans that are installed into drywall with the right tools and techniques can remain mounted on the ceiling for more than 50 years.
The key to installing a fan that mounts firmly to the ceiling is to follow proper installation practices. The fact is, drywall cannot hold a ceiling fan long term, but ceiling fans can be successfully installed into drywall ceilings. Let’s unravel what is meant by this.
Drywall can’t hold a ceiling fan. Drywall’s average load capacity is 1.2-1.6 lbs. Ceiling fans weigh about 8-50 lbs. However, ceiling fans can still be installed in drywall ceilings if the junction boxes (correctly rated) are attached to joists in the ceiling. The joists then support the weight of the fan.
Average Load Capacity of a Drywall Ceiling
Drywall is made from thin panels of gypsum board. It comes in varying thicknesses (between 1/4″ to 5/8″), and the thicker the material, the higher its load-bearing capacity.
But regardless of the thickness of your drywall ceiling, it simply is not designed for weight-bearing. On average, a drywall ceiling can hold between 1.2 and 1.6 lbs per square foot without any form of support.
Drywall Cannot Hold a Ceiling Fan
Drywall isn’t strong enough to hold heavy items without any form of support. As I stated earlier, your drywall ceiling can only hold about 1.2 to 1.6 lbs of direct weight for every square foot.
The problem here is that ceiling fans do not fall within that weight range. Ceiling fans typically weigh between 8 and 50 lbs.
Installing the ceiling fan directly to your drywall ceiling puts it at risk of collapsing. This is because, in addition to their weight, ceiling fans also vibrate while running, putting extra pressure on the ceiling.
But you see ceiling fans in drywall ceiling boards all the time. So, are millions of people having a bit of a gamble going on to see how long until the fan falls out, or is there another explanation? As you may have guessed, there is another explanation.
Fan Attached to Junction Box
These ceiling fans are (hopefully) only sitting in the drywall ceiling as opposed to hanging from it. The actual weight of the fan is held by a junction box that is attached to the ceiling joist, which is more than capable of handling the static and dynamic weight of a ceiling fan.
A junction box is an enclosure that houses electrical wiring connections. It is used for various electrical projects but in ceiling fan installation, it performs the added function of supporting the weight of the fan.
To ensure that the fan is properly supported, the junction box is connected to a ceiling joist.
Junction Box Must Be Listed for the Fan’s Weight
Ceiling fans come in varying weights and not all junction boxes will be appropriate for supporting every weight class.
The National Electric Code (NEC) demands that all fans weighing 35 lbs and above be supported with a junction box that is listed for ceiling fan support.
If the junction box came with the fan, then you probably do not have any reason to worry. But if it’s an old box or one you purchased yourself, then you should ensure that it is not only ceiling fan rated but that it is appropriate for the weight of your fan.
You can check your fan’s user manual for the manufacturer’s recommended junction box weight-bearing capacity. However, most fan-rated outlet boxes support a minimum weight of 50 lbs, so they’d probably be ideal for most household ceiling fans.
Using the wrong junction box creates a safety hazard, as it might be unable to support the fan’s weight, especially while it’s running, putting the fan at risk of wobbling or worse, falling out of the ceiling.
Maximum Allowable Ceiling Fan Weight
The weight of a ceiling fan is dependent on a couple of factors.
- Thickness and number of blades
- Weight of the motor
- Fan material
- Fan size
- Additional accessories like lights
Fans with metal blades usually weigh more than those with wooden or plastic blades. But the weight of the fan is mostly determined by its motor.
According to the NEC, even fan-rated junction boxes are not allowed to support fans of over 70 lbs. People don’t typically use a junction box that can hold up to the exact weight of the fan. This is because, as mentioned, dynamic weight is greater than static weight.
How Does the Junction Box Attach to the Joist?
The kind of junction box you use would be dependent on the installation location. If a joist is directly above or beside the installation hole, you can install the box directly. But if there is no joist, you would have to connect a brace before attaching the junction box.
Here is a helpful video on choosing the right junction box:
This is possible if the installation spot is beside a joist or if there is a joist directly above the installation location. If you meet the criteria for direct installation, here are some boxes you can use.
- Box with reversible side brackets
- Pan box
- Saddle box
A pan box and a saddle box are installed directly below the joist while a box with reversible side brackets is attached to the side of the joist.
- Does not require a brace.
- Costs less to install.
- Suitable for both new and old work (old work doesn’t require attic access and new work requires access to the attic).
- Might require attic access, especially if it is being attached to the side of the joist.
- The joist has to be directly above or beside the hole.
Attachment Via a Brace
If the installation hole isn’t directly below or beside a joist a metal brace is connected between adjacent joists and the box is attached to the brace.
If you do not have attic access, instead of purchasing a brace that needs to be screwed into the joist, get one that features teeth that can be twisted into the joist.
Braces are available in new work and old work varieties, so you have to ensure that you purchase one that suits your need, especially if you do not have attic access.
Most manufacturers provide a ceiling brace and box kit, so you can buy them together rather than purchasing them separately.
- The junction box can be installed even if the installation hole isn’t directly below a joist.
- Suitable for both new and old work.
- The brace provides additional reinforcement for the fan.
- It allows for flexibility in the placement of the ceiling fan.
- Might require attic access if the brace needs to be screwed into the joist.
- The junction box cannot be installed without a brace.
- Costs more to install.