Toxic Apartments: Housing shortcuts leading to mold, mildew and misery – Part 1

This fall, Oregon State University will welcome almost 26,000 students back to a town with an already abysmal apartment vacancy rate of less than 1%.  In fact, student enrollment has increased by 5-8% annually during the last several years, and will continue to increase by an average of 2% over the next five years.  While this would raise enrollment to almost 30,000 students, the eventual goal is closer to 35,000.  OSU hopes to expand its student housing accommodations in the near future; more on-campus housing would help to alleviate the current off-campus housing crunch, although this is dependent on the availability of state funds.  Meanwhile, the response to the increasingly overwhelming demands for student housing is in evidence – new “affordable” and “energy efficient” multi-family apartment complexes are springing up like weeds all over town.  While this is obviously taxing for the community (read any of the numerous local housing problem articles and you’ll find a plethora of quotes from concerned residents), the issues are not nearly as black and white as they may seem at first glance.

Photo by Genevieve Weber


Ring Around the Carpet


My Corvallis apartment was built in the 1970s.  At the time, a new product called OSB (oriented strand board), made with wood chips glued together by petroleum-based adhesives, was hitting the market and making a major impression – cheaper than plywood and just as strong!  So my apartment, framed with untreated 2x4s, was sheathed in a cocoon of OSB.  The contractors hoped to market the homes as “energy efficient,” which really just meant air-tight.  Because the OSB in the walls of my apartment can’t breathe, the wood is now swollen and rotted, and – most problematically – colonized by mold.


“Moisture is endemic in houses, it’s always there,” says Jeff Morrell, a Distinguished Professor of Wood Science and Engineering at OSU.  “You have your breath, the bathroom, the washing machine, and if you don’t exchange enough air, you’re going to build up moisture.  If you let moisture build up, it’s going to move through the wall to the cold surfaces and condense.  You’re going to get mold and decay, and that’s pretty typical in newer buildings.”


I’m betting a lot of you out there feel my pain (in your lungs, I mean).  Fungi are the most common wood destroying organisms found in Oregon homes, ahead of termites and other insects.  Breathing mold spores over long periods of time can lead to serious health complications, especially in people with prior conditions such as asthma and allergies.  Reactions to mold are common in both allergic and non-allergic individuals, and can be delayed, so your allergy or chest cold symptoms may not seem associated with mold.  It’s also very difficult to determine which few individuals will experience severe allergic reactions until they’re actually confronted by an onslaught of mold.  While it’s most commonly visible as a dark stain in the dampest areas of the house, such as bathrooms and garages, mold can be well-hidden behind drywall, wallpaper, ceilings, and plumbing structures.  Have a persistent, annoying, and sometimes debilitating cough?  It’s time to check your home for a fungal invasion.


A slew of apartments in Corvallis share this obnoxious problem, even some built as little as 10 years ago.  Some constructed in 2007 look as though they might be headed for a similar fate.  But the issue isn’t just cheap materials like OSB, which do have to pass minimum building code requirements.  Intact OSB is actually quite strong, and the cultivation and harvesting of small, fast-growing trees for OSB-type materials is much more economic, and frankly a more sustainable forestry practice, than harvesting the larger trees required for sturdier plywood.  An important aspect of building structures with OSB is leaving an air space to allow the material to breathe; otherwise it stays wet for long periods of time.  OSB does not handle moisture as well as plywood, which is significantly more efficient at passing and redistributing water, and drying when it gets wet.  OSB warps and swells and becomes structurally less sound when it soaks up water over time, and it never recovers its original integrity or shape.  The breakdown of carbohydrates in the moisture-damaged wood makes OSB much more susceptible to microbial invasion.  Think about those incomplete townhomes you pass on your way to work every day; that unprotected OSB has been soaking up rain for weeks.


“As with a lot of the newer building products, OSB in particular is not a really durable material, so you have a combination of a lot more moisture trapped and built up, and you have a material that’s not durable,” Morrell added.


The best (and only) way to control mold is building to keep the susceptible wood structures of the house dry in the long term.  We as tenants can play a huge role in preventing moisture build-up by using exhaust fans in our bathrooms and kitchens, and opening the windows for ventilation.  But maintaining minimum moisture levels becomes problematic when cheap homes, which are subjected to condensation from temperature changes, plumbing, washing machines, and much more, are built air-tight for energy efficiency.  As contractors work to meet increasingly stringent energy use standards, this dilemma won’t be solved any time soon.


“What we’ve seen over the years is certainly a tightening of buildings and a movement in our building codes to become more energy efficient,” affirms Dan Carlson, Corvallis’ Development Services Division Manager.


What is Oregon doing to control these issues?  While negligent tenant practices certainly lead to a lot of moisture build-up in homes, so do rain, poorly designed landscaping and irrigation, normal everyday activities like brushing your teeth and running the dishwasher or washing machine, and of course initial moisture sealed inside walls.  What are Corvallis contractors doing to help make buildings at least a little more mold-resistant, and what changes have been made since that most recent slew of apartments was constructed a few years ago?  Find answers to these questions and more in next week’s issue of The Corvallis Advocate.


Check out Part 2 of this article here!


By Genevieve Weber