There’s an old saying “a house is only as good as its foundation.” There’s little denying this reality but the same case can be made for good, well ventilated, attics.
Attics are an essential, usually overlooked, element in the overall functionality of our homes. When working properly, they insulate, keep out the elements, reduce energy costs, maintain a comfortable interior environment and help ensure good IAQ (indoor air quality).
The key to a well-functioning attic is proper ventilation. Outside air should flow from the soffit vents freely, over the insulation and out through roof vents on ridge of the roof line taking moisture with it.
A well ventilated attic will help keep you warmer in winter and cooler in the summer.
A poorly ventilated one will the do inverse. It will raise your heating and cooling costs, damage shingles through ice dams, ruin insulation and as a consequence grow black mold. This black mold usually stains roof decking and rafters turning large sections, often the entire attic black, grey and even white and fuzzy. As the attic is not properly vented and traps moisture, this problem does not dissipate, but rather worsens over time.
Improperly installed bathroom and kitchen fans also contribute to the problem by supplying humid air into an attic rather than sending it outside through the roof.
Speaking of roofs, many do not have enough roof vents to allow air out and contribute to attic venting issues. Sometimes they are even covered over when the roof is replaced or extras are not added even when it’s clear they are necessary.
Unfortunately, home owners, even those who do regular maintenance on the rest of the house, often neglect to inspect their attic even annually. By the time someone, say an electrician installing pot lights, home inspector or whoever goes up there the black mold problem has been progressing for years.
Mold remediation companies are often called in at this point. Especially when the home owner is trying to sell. The buyer’s home inspector looks in the attic and its “black.” Not really a selling feature.
Not only does this indicate a mold problem, and all related possible health issues, but also a structural problem with the home. The shingles will not last as long as they should. Sometimes the insulation is damp or wet and also growing mold. Energy costs will be higher than they should be. The home won’t be as comfortable in the summer or winter as a properly vented home is.
For these reasons attic mold is a red flag for potential buyers of a home and thus a “deal killer.” Like asbestos, buyers are not interested in buying someone’s environmental problem knowing their health may be at risk and that they will need to spend thousands to fix it. If they are, they will want the issue(s) dealt with or a very substantial discount on the sale price. Often they will simply walk away from the deal fearing for their own health and safety.
The reality of venting problems and resulting mold is they are totally preventable.
Often it’s a simple matter of removing fiber glass bats or blown in insulation from the rafter bays at the soffit level of the roof which were putt in under the mistaken assumption they would “keep the heat in.” In older homes, often under the newer perforated vinyl or aluminum soffits there are not enough holes cut in the original plywood soffit material. It may look go from the outside but if this is the case not enough air is getting into the attic from the soffits.
Adding a few roof vents and fixing those fans venting into the attic will also help correct the problem.
Adding more insulation to an attic with venting problems is a bad idea. Unfortunately, in recent years, many home owners have unwittingly contributed to the attic mold problem by doing just that.
Starting in 2007, federal and provincial grants, both expired in Ontario in 2012, to increase energy efficiency have in a way contributed to the attic mold problem. In their rush to get free money from the government many home owners had insulation added to their attics, without fixing venting issues. With these programs in effect one could actually make money off insulating your attic. This of course encouraged many fly by night contractors who either didn’t have the knowledge or the scruples to tell home owners, when they had venting issues.
By adding more insulation, especially over vermiculite, (a whole other post) they made an existing problem much worse. Now that the grants and fly by nighters are gone, many home owners are finding out that they’ve been “penny wise and pound foolish” facing a mold clean up and re-insulation bill several times greater than the quick money they got from the “quick” and “cheap” fix a few years back.
Reputable insulation firms will tell perspective clients when they have venting problems and often refuse to insulate attics until the issues are corrected. Same goes for vermiculite, but again this is another post altogether.
All of this bleak news may leave may home owners asking “what do I do about my moldy attic?”
The solution(s) are there, but they’re neither “quick” nor “cheap.”
Mold abatement of an average attic can take several days. Before removing the mold from the attic a mold abatement company will need to separate the rest of the home from the attic work area via HEPA filtered negative air pressure. This will prevent any black mold spores released during the abatement process from getting into the rest of the home.
No matter what method is used to strip the mold off the wood decking and framing in the attic it will need to be invasive and aggressive. Chemical treatments alone will often only mask the problem. Real solutions often involve Soda blasting or dry ice. These methods will physically strip the mold off the attics wood surfaces. Once this is done the insulation will be totally contaminated and must be removed. Next attic the attic will then be HEPA vacuumed and treated with a “Non-Toxic” mold inhibitor.
The advantage once all of the insulation is gone it’s often easy to assess and fix venting issues before having a professional company comes in to re-instate the insulation.
This is also a good time to make sure fan ducts in the attic are solid steel ducting (not plastic or flex hose) meeting the OBC (Ontario Building Code), go out vertically through roof, are insulated, and to seal penetrations from the home that go into the attic. This is often carried out the by the insulation contractor as an “extra” that is well worth the expenditure.
A properly remediated attic will be clean, properly vented, and can be re-insulated with R50 (industry standard) blown in insulation. In turn the home will be more comfortable to live in, more energy efficient and most importantly not allow mold to return.
The moral of the story is that home owners need to lose the “out of site out of mind” mentality about attics. Like home buyers, through their home inspector, home owners should inspect their attics regularly and fix and problems, venting or otherwise, or they may find themselves with a very costly black mold problem.
Next time, the other attic problem that will not go away on its own: vermiculite.