How to Vent a Bathroom Fan Through the Roof | Step by Step Process

Involving your attic or roof for bathroom ventilation is not a very friendly idea to many. And there are obvious reasons for the disliking. However, sometimes the situation makes us have no choice but to follow that route. And that’s when knowing more about how to vent a bathroom fan through the roof becomes compulsory.

Of course, you want to know more about the possibility, limitations, and also if there’s a way to sidestep any risks. Well, today let’s cover all that for you in this piece of writing.

The Process of Venting a Bathroom Exhaust Fan Through the Roof

There are other windowless bathroom ventilation routes to go for. However, if there’s an absolute necessity for venting the fan through the roof, make sure to insulate duct. So that there are no condensation issues coming on. There are ducts available in-home centers with wrapped insulation. Sometimes people get really hasty with the installation. Let’s get into the actual process below.

Start by Making a Reference Hole & Marking the Ceiling

For the proper bathroom fan installation, you need to draw a mark right on the ceiling. This is where fan will go. The best location for this is right between the toilet and shower. Now create a reference hole on ceiling with a spade bit into attic. It should be ideally extra-long, 3/7-inch diameter for better results. Make sure you climb up to the attic and clear any insulation away closer to this hole. You are going to use this hole for understanding where the fan should be exactly positioned.

The two joists that are near your reference hole should hold the vent fan directly in between. At least try to make it this way. The pipes or obstructions that are nearby should get your attention too. You need to observe the final positioning of fan based on the reference hole.

Now go back to the bathroom and measure intake port of the fan. You should find out this dimension for understanding what size hole needs to be there in the ceiling. The reference hole will play a landmark that will help in traversing the measurements from attic to ceiling here. To create the rectangular outline on the ceiling you can use a layout or framing square.

Creating the Intake Hole & Working on Fan Position

You can get a jigsaw, drywall, or even reciprocating saw for this next step of venting a bathroom fan. Use any of these to cut through the layout lines on the ceiling. Make sure to wear proper goggles and respirators.

As you reach the finale of making the rectangular cutout, use one of your hands to support the waste piece. So that it does not fall unexpectedly. In the attic, you need to work on the outlet port of vent fan housing now. Simply attach a 4-inch, 90-degree duct elbow right here on this outlet. You can use some foil duct tape for securing the elbow with a port in bathroom fan venting.

Get rid of the hole that is one fan housing’s sideway. And then attach it with a cable connector. The sides of fan will protrude tabs where you need to slide four metal brackets next. And finally, right between the just middle part, you need to set the vent fan making sure it is centered on ceiling hole.

Attaching the Fan to Joists & Creating Duct Hole Through Wall

The bracket needs to come in close to the joist’s side, so extend them until that happens. Using a solo 1½ inch drywall screw, you need to secure all brackets. The wall cap kit should come with a flexible duct. You need to carefully slip one end of it over elbow. The one that is secured to vent fan. Using some foil duct tape, secure the whole thing next. Then the cable needs to feed through connector. You can go with existing or new cable here. Finally, tighten the screw for securing cable.

Now we enter the main part of process. There should be a flexible spot on the inside of attic that can allow the flexible ducts to exit house. It should be located right between the two wall studs and also it needs to be within 6 feet of vent fan. To locate the spot from outside, simply use a few reference measurements. Use this to create marks on the hole location. And then use a 4-inch hole saw for creating this duct hole through wall.

Exhaust Duct to Wall Cap Attachment & Installing Wall Cap Next

This part is about the bathroom exhaust fan roof vent cap. It’s important to make sure the wall cap’s connector duct is securely attached to duct end. Use a fold cut tape here. You do this after attaching the wall cap to outside wall. The free end needs to carefully stretch towards wall that is outside.

Now if you’re fastening a 12-inch-long connector duct, start by sliding the wall cap into duct hole. You need to push it to sight enough against the siding of house. If there’s a space that doesn’t contact the wall cap, then use a cut foam rubber gasket to fit here. Apply some silicone adhesive on the siding after removing wall gap. You also need to gasket around the hole. Then slide the cap inside hole. Give it a gentle press. Use a stainless-steel screw to secure it finally.

Wire Connections & Grille Attachment

Get the blower motor out from vent fan housing in the bathroom. Keep screws aside. You need to detach the built-in receptacle next. This will expose the wiring. Join the wires of same colors and feed into housing electrical wires, use nuts to secure them.

The bare copper wire wraps around a green grounding screw. And then you can tighten the screw. Get the receptacle back to its position. And use the kept aside screws to secure things. Wrap the bare copper wire under green grounding screw inside housing and tighten screw.

Push the plug inside the receptacle while raising blower motor up. Use screws to securely attach the motor back to its place. Tightly attach the grille on the ceiling. Turn the power back and test everything. You can spread the mounting wires a bit if the grille refuses to hold tightly against the ceiling.

Final Thoughts

And that was all about how to vent a bathroom fan through the roof. Be very sure about each and every limitation before you actually try this. The roof venting can be still risk-free if you do it the right way. You can also contact a professional for paying a visit and checking the circumstances. They just might have a better alternative that you still can’t seem to find.

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