We are set to close on our house in about three weeks and one of the problems that the inspector noted was that the vent in the guest bath vents into the attic (never going outside) and the master bath does not have a vent at all.

We do not have much experience with DIY home repairs, but would like to do as much ourselves as is feasible so we have a better understanding of the house and how it works.

First of all, how simple would it be to extend the vent from the attic to the outside, and what would we need to do so without causing additional problems with the roof, and secondly, how easy is it to install a vent in a bathroom that does not have one?

  • I don't have anything useful to add, it's just curious that I found the exact same situation when I moved into my house! I was able to vent out the gable end wall. The only tricky part was fishing a new wire into the wall switch box, as the roof was very low at that location. The M. bath did have a window, but who wants to open a window to shower when it's well below 0F outside? Congrats on your new home!
    – bcworkz
    Mar 31, 2013 at 17:59

1 Answer 1


Congratulations on your new place! Installing a bath fan is a somewhat ambitious project for a novice DIYer. You have to:

  1. Do electrical work to wire the fan and switch.
  2. Mount the fan in the right location.
  3. Run ductwork from the fan and outside, usually via a roof or wall vent.
  4. Avoid doing much damage to your ceiling when cutting into it.

The biggest challenges here are usually in the vent installation. If you can go out through a wall or gable, a vent can be easy to install, just requiring a round hole and some caulk. If you have to go up through the roof, there are a number of subtle ways you could install the vent incorrectly that would not be immediately obvious but would increase your chances of a future roof leak significantly. Try searching the site for "roof vent flashing". Also, depending on the height and angle of your roof, you should think about whether you're able to climb up safely.

The other potential issue is the electrical. Like roofing, it's easy to make a mistake that you might not notice for a while, but the risk is more severe as you could create a fire. You could also make a mistake that shocks and injures you. So if you are really new I'd recommend you start by learning how to safely do things like replace outlets and light fixtures first.

Most of all, make sure you take the time to understand what you are doing. A challenge is always fun, but you will probably have plenty more opportunities!

  • As a followup, if we decide it is too ambitious for a DIY project, who would we be looking for to hire? An electrician and a roofer? HVAC? I also watched a video on roof vent flashing showing how to cut the shingles and layer them on top of the vent, seemed relatively simple, but that was just watching a video. Mar 31, 2013 at 20:02
  • You're right -- if hiring out, you'd want an electrician to install and wire up the fan, and a roofer to install the vent penetration in the roof. Apr 2, 2013 at 16:07

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