Modern-day homes leave little space for proper ventilation. Many people think small windows work fine for venting bathrooms. However, that’s not enough to prevent mold formation on the wall.
If you’re having trouble venting the bathroom through the roof, then a soffit could provide an easy solution.
This article will discuss how to vent a bathroom fan through a soffit in easy detail. Hopefully, for any DIY enthusiast, it will be an enjoyable experience.
Advantages of Venting Bathroom Fan Through Soffit
Soffit is basically a finishing material that is used to cover the underside of a roof overhang. Its purpose is to enhance the aesthetic value of the home.
We generally see the sidewall or the roof being used as vents for bathroom fans. But sometimes, using soffit instead of vents could prove to be preferable.
Avoid Making Holes on the Roof
If your roof already has multiple holes in it, then it might not be a good idea to make another. Too many holes increase the chances of water leakage during heavy rain.
Short Duct Length
The fan hose duct requires covering the shortest distance when you install venting through the soffit. You need to have a quick bend on the attic floor and underside of the roof.
No Back Drafting
Since wind moves horizontally, the wind could blow cold air back into the bathroom when you have a vent on the sidewall. Venting the fan through the soffit reduces the risk of such backdrafts since the installation angle is different from the wind.
Preserving Room Heat
Using a soffit vent creates a thermal trap because the humid air running through the soffit lies in a horizontal position. If you turn the fan off, the air remains suspended there.
This creates a pocket of warm air, which prevents the outside air from flowing into the bathroom.
How to Vent a Bathroom Exhaust Fan Through the Soffit
While installing the venting system, you should be careful so that the soffit doesn’t get damaged. Keeping this in mind, the steps of installation are as follows:
Step 1 – Try to Avoid Bending the Hose
When ventilation is in question, it is essential to keep the air passage straight and clean as much as possible.
One of the most important aspects of soffit ventilation is getting a straight vent hose with the least bends. Fewer turns in the hose mean better circulation of air.
Another reason to avoid bends is to reduce the condensation of water. The air venting through the passageway is often warm and humid. If that humid air is suspended in that area for too long due to many bends, it can cause condensation.
Step 2 – Ensure the Right Vent Hose
The best way to vent a bathroom fan is by ensuring you have a suitable vent hose. There are multiple types of vent hose available in the market with different diameters and sizes.
So, before buying, you need to check the size of the bathroom fan to get the correct sized hose.
Modern bathroom fans are high-powered and use duct hoses of 4-inches or 6-inches diameter. Although some old houses still use 3” duct hoses.
If the hose diameter is smaller than the bathroom fan, it doesn’t circulate the air as much as the fan needs to. So you need to be careful while picking the vent hose. If you already have a vent hose, replace it with the right-sized one if necessary.
Step 3 – Make the Soffit Hole
Installing bathroom vents can sometimes be complicated. If you’re not an experienced DIYer, it is better to leave making this hole to a professional.
You need to make the soffit hole in the proper location and as perpendicularly close to the bathroom as possible. The hole needs to be between the roof lookouts, which are also known as the rafters.
This area needs to be marked first, so you don’t make the hole in the wrong place. You can get a template from the manufacturer of the vent cover. Using that template helps a lot and reduces the chance of making the hole bigger or smaller than necessary.
When you’ve marked the soffit accurately, use an adjustable or fixed hole saw to make the hole.
You can also use a tin snip or a jigsaw instead as well. Now polish the edge of the hole to make it smoother. The most important thing is to make sure not to damage the soffit during this step.
Step 4 – Cover the Vent Hose
Pass the hose through the attic and the soffit hole. Pull the hose out some more to make sure it straightens out inside and there remain fewer bends. You could cut off the extra hose since you won’t need that.
Use a metal clamp to join the soffit cover with the vent. A screwdriver or a socket wrench can be used to tighten this metal clamp. Use foil tape, so it doesn’t fall off.
Then push this base up into the hole. Sometimes it has wings, so you don’t need any screws. If it doesn’t, then you might have to drill some pilot holes on the soffit to attach the cover with screws.
Step 5 – Connect the Hose to the Fan
When connecting the hose and the fan housing, the steps of venting bathroom fan through soffit or roof end should also include fixing a cable connector there by removing the knockout hole.
How to Vent a Bathroom Fan Through the Roof?
When your bathroom is located in the middle of the house, then you have no other way but to use the roof for ventilation.
The method for using the roof is almost the same as the soffit. But instead of making the hole on the soffit, you need to make it on the roof. You also need to cover it with a roof vent hood or a roof vent cap.
If you have an old roof, don’t go poking new holes into it. It is excellent to vent bathroom fan into soffit since it has some major advantages.
It is not a very difficult task, and when you know how to vent a bathroom fan through a soffit, it doesn’t even take more than an hour.