Bathroom vents could be ruining your homes roof and health
If you have had the pleasure of crawling through as many attics as we have, you will have seen a thing or two that just makes you shake your head. From snake skin sheds, to scary electrical connections, to exhaust fans just venting to the attic. While finding a 5’ long snake skin shed in your attic might make you skin crawl a little knowing a snake that big was hanging out in your attic, it's not nearly as worrisome as an exhaust fan vented directly into your attic.
Unfortunately, we see it all the time. The easy route is to install that bathroom exhaust from below and never go into the attic to properly vent it out the roof. I get it, who really wants to crawl through all that insulation. And besides, there are roof vents up there that should carry everything out of the attic right. And on top of all that, if we don’t install the roof piece correctly we can cause a roof leak that will ruin everything below. So I get it, just shove the vent in the attic space and call it all good.
Unfortunately, that is one of the worst things you can do for the life and health of your home. The two main components we see vented into an attic are bath fans, closely followed by kitchen range hoods/vented microwaves. In both cases, we typically turn those fans on under 1 of 2 conditions: Vent the excess moisture from the room, or expel unfavorable fumes from the room. Both cases are problematic.
Let’s look at case number one: using an exhaust fan to remove excess moisture from the room. Whether it's in the kitchen as we are boiling pasta or in the bathroom during a steaming hot shower. If you have spent any amount of time in the remodeling industry, watched any amount of HGTV or Holmes on Homes, you know that water, in any form, will wreak havoc on your home. One of the biggest challenges of building/remodeling is to keep water from getting into the structure, and when it does, shed it out and dry it off as fast as possible. Therefore, it makes entirely no sense to dump hot steamy air into your attic. What happens with a glass of ice water in the summer? It collects condensation. Now imagine the plywood of your roof is the glass, and the hot steamy air from your shower, laden with moisture, is the summer air. The air coming from the exhaust fan is going to condense on the plywood of the roof and eventually lead to rot. What’s more expensive than a roof replacement? A roof replacement that also includes decking replacement due to rot.
“I don’t run the vents when I shower just when we need to exhaust unwanted smells, so I should be okay”. Are you sure about that? Simple science tells us that air in must equal air out. So any air you exhaust from your home must be replaced. So let me ask you, do you know where your new fresh air is coming from? “I open a window when we run our exhaust fan”. Good! But what about when the water heater runs? Or the furnace? How about the dryer? Are you opening the windows when these appliances are on as well? These appliances exhaust air outside when running, and that air too needs to be replaced. If you live in an older home with gas appliances, there is a good chance there are 2 metal pipes in or near your furnace and water heater area. These pipes are supposed to serve as fresh replacement air for the furnace and water heater. Can you guess where these pipes run? If you said your attic, you would be correct. So now, every time your exhaust fan, dryer, furnace, or other device that expels air outside runs, it needs new fresh air. Air will take the path of least resistance, and we just put 2 10” pipes into the attic for easy access to fresh air. But wait, isn't that where you are dumping those unwanted fumes from the bathroom and stove? Hmm.
“But my attic is vented so it's okay to just run the vent to the attic” says most homeowners that have growth on the underside of their roof. In most cases, roofs are undervented. Whether it's a lack of soffit or gable intakes, or insufficient or improperly placed exhaust vents, most attics are undervented. Even a properly vented attic in our region is going to be the same outside temperature in the winter, and over 120* on hot summer days. Cold roofs and hot steamy shower air don’t go well together.
The bottom line is simple, your exhaust vents must be vented to the exterior of your structure. If not, you are decreasing the lifespan of your roof and putting in jeopardy the integrity of your structure. If you have existing vents in your attic that need to be run outside, we can help. If the damage is already done, and your sheeting and truss already have growth and rot, then my friends at ZCI General Contracting are who you need to call for roofing repair and replacement!
