Attic Ventilation

You may have a ventilation issue on your New home.

People are not perfect.  Despite the name of my business my inspections are not perfect, but I strive everyday to make them as close as I can.  People build homes and no matter what there is always something that could be adjusted, maintained or updated to help the home be more “perfect.”

These improvements can sometimes be debatable but some things, like the proper ducting and expulsion of bathroom exhaust, are not negotiable.

The little exhaust fans in the ceilings of our bath and laundry areas and often forgotten about.  These little fans can collect and concentrate significant amounts of moisture.  If the vapor that they collect is not expelled out of the home it can cause moisture related issues like deterioration, fungus, termites, beetles, ect…

Traditionally the fans are ducted with a flexible metal duct up to a roof vent.  Where the air that is leaving the attic carries the moist bathroom air up and out of the attic.  It is currently acceptable to vent the ducts to the soffit but I am definitely not a fan of this idea because the soffit vents are intakes andall of the warm moisture laden bathroom air that is blown out of these vents is usually separate back into the cool attic. (Find more of my disdain towards bathroom vents exhausting at the soffit vents.)

missing hole for Salem Oregon attic vent

I popped my head up into a new home’s attic the other day during a home inspection and noticed something was missing. The bathroom bans all worked fine, the ducting was routed properly up to the upper roof vents, there was just one key component that was not installed properly….

The hole for the roof vent, although cut through the OSB sheathing, had not been cut through the roofing shingles and building paper.

The home was so new there had not been any substantial moisture added to the attic and repairs simply involved cutting a hole.

improperly installed attic vent in this Salem, Oregon home.

Advertisements

Those darn drafty attics.

On a home inspection the other day I popped my head into the attic space of a vintage 1950 home. At first glance the attic felt unusually warm and moist. From the outside the gable vents appeared to be large enough and should have kept this attic effectively ventilated however the current renter had some other ideas. He told me that he had been in construction for years and was currently unemployed.

This vintage home had a minimum amount of insulation and the gable vents were covered with plastic!! All of the warm moist air coming up out of the home was being trapped in this unheated, unvented, ideal mold growing limbo. The roof sheathing was covered with a soft and fuzzy patina, very artistic but not very pleasing for home maintenance and air quality.

The moral of the story is those openings in your attic and there for a reason and very important. They are not there to make you suffer when it is time to pay the heating bill. Insulation should be used on HEATED surfaces. Your attic is not a heated space. The floor of the attic is next to a heated space and this is the only surface that should be insulated. The rest of the attic should have enough vents to keep the attic as close to the exterior temperature as possible. This will vent excess moisture, cool the roof system and provide a good environment for maintenance of the structure of the roof.

Home inspections in Salem, Oregon. Mold, Inspector, Keizer

Grow mold in your attic (vent to the soffit)

Ah mold. It is such a hot button. I know just by putting the word MOLD into my title this post will get attention.

People are interested, but I am still surprised at the lack of knowledge or the inaccuracy of knowledge (even you agents who need to know the basics).

This is not intended to be a general knowledge post. (go here for that) This is a heads up for everyone on the issues concerning acurrently accepted means of exhausting bathroom vents. It is acceptable, by International building codes to duct bathroom vents to an attic vent (any vent). This is usually a good thing and definitely better than venting directly into the attic. Recently I came across a very new home (only four years old) that had some mold growth in the attic. Not really a huge amount, however mold spores are microscopic and you cannot determine if it is affecting Indoor Air Quality without getting a lab involved. With closer investigation it could be noted the exhaust fan for the shower and toilet area was ducted to the nearby soffit vent. This is currently acceptable by building standanrds however in this case it was the root of the issue.

The way an attic vent system works is like a chimney, as the roof heats cool air is pulled into the soffit vents and hot air is exhausted out the ridge vents. So as the diligent home owners ran their exhaust fans during the steamy shower all of the warm steam was pointed at an intake vent!! All the moisture exhausted toward the vent and promptly turned around and was able to condense on the cool attic surfaces as the soffit vent did its job.