Happy Valentines Day to all those lovers out there. If while celebrating you notice you have an indoor air quality issue or need mold testing, mold inspection or mold remediation call and we’ll give you our Valentines special.

The snow cover may look like a winter wonderland, but it can wreak havoc on your roof. It’s that time of the year where we have to be concerned about weather affecting not just our families, but our homes as well. Ice damming on your roof can cause considerable damage to the structure.

Mold and especially wood rot can be like unwelcome guests and affect the indoor air quality. Proper ventilation in the attic is essential to remove moisture and gases that build up and prevent mold growth. A properly insulated and sealed attic is key to preventing ice damming. Allowing warm air flow from the conditioned space (the living space) to come into contact with the underside of the roof deck is what you want to avoid.

A consistent covering of insulation being careful to not block the soffits by using baffles is the first step. Newer homes with the right amount of insulation can still have ice dams that not only cause leaks, but allow water to get behind the cladding system (what covers your outside walls).

Stopping air from leaking into the attic is the second. Penetrations from wiring, plumbing, ductwork and light fixtures are some of the avenues that warm moist air can take to leak into the attic space from the heated part of the house. This will heat the underside of the deck and cause snow to melt and start the process of ice damming.

When water from ice damming gets behind the vinyl siding or your stucco it can get to the sheathing that holds your siding and cause damage. This can result in stucco repairs and necessitate stucco remediation that is costly.

This time of year we are often called out for problem with mold growth in attics. The main reasons for this to occur are as follows:

* Improper attic ventilation
* Venting bathroom exhausts into attic space
* Venting clothes dryer exhaust into attic space
* Inadequate insulation or missing insulation
* Ice damming
* Poor installation and/or aging of roofing materials

I’m going to start with the first one, improper attic ventilation. Proper ventilation is recognized by building science experts as a requirement for preventing microbial growth, preventing shortening the life expectancy of roofing materials and removal of potentially harmful gases via the stack effect.

All of the building codes – BOCA National Building Code, International Building Code, Standard Building Code and Uniform Building Code require attic space to be ventilated.

Generally, codes require a minimum net free ventilating area for attic vents to be 1-150 ratio of the attic space. This rate can be adjusted to 1-300 if attic vents are balanced. Some of these ventilation requirements are more than 60 years old and considered inadequate by some. ASHRAE’s (American Society of Heating, Refrigerating and Air Conditioning Engineers) position on ventilation is an attempt to prevent condensation from occurring on the underside of roof sheathing. ASHRAE’s 1997 Fundamentals Handbook cites several disadvantages to providing attic ventilation. Basically, in warm humid climates venting can increase vapor pressure (relative humidity) and condensation issues, so, it has to be looked at on a case-by-case basis. For colder climates, the benefits generally outweigh the disadvantages. We are in what we call a mixed-use climate. It is generally agreed by building science experts and myself in the building science arena that proper attic ventilation is the way to go.

Venting bathroom exhaust fans into attics is something we see quite often. Let’s look at why this is a mistake. Mold needs four things in order for you to suffer the problems associated with it, they are: mold spores, a food source, the right temperature and moisture. The mold spores come from outside. Their role is to digest dead organic materials, without them every blade of grass and tree that died would not decompose. Nutrients (food source) for mold growth are abundant in your attic, mold prefers cellulose. Wood is mostly cellulose and lignin and I don’t have to tell you that your house is built with wood framing members mostly. Believe it or not, some builders use paper baffles rather than Styrofoam to keep the soffits open. We have different types of insulation and one of them is blown-in cellulose. So, as you can see everything is in place for a mold remediation project when you add the fourth element – moisture.

Don’t forget that this applies to clothes dryers as well. You must evacuate moisture from your home and when it comes to exhaust fans and attics – get it to the outside. Translation, vent through the roof insuring that a proper boot and flashing integrated under the shingles around the vent stack are in place. Another good practice, but often unseen even on exhaust fans that are vented though the roof is insulation. Keep in mind you’re sending hot moist air through metal exhaust pipes through a cold attic in winter. You can and will get condensation and consequently mold growth, so wrap that pipe with fiberglass insulation.

If you’re not sure or not comfortable checking for yourself whether you have proper ventilation and whether or not you have a mold problem in your call, call Advanced Mold Diagnostics at 610-328-4350 and we will provide you with a free telephone consultation to see if we can help.

Okay, so we understand we have to ventilate our attic spaces, what exactly does that mean to the average layperson?

My apologies to any of my environmental consultant or building science expert friends who might saunter in here. This basic primer is geared more to helping the property owners who don’t understand the basic principles. Keep tuned though, as we’ll move onto some very interesting concepts regarding attics and ventilation concepts and huge energy savings. Well, first off, some of the components that you might see or need to understand would be:

* Soffit vents
* Ridge vents
* Gable vents
* Turbine vents – passive
* Powered fans

Soffit vents are where your roof extends beyond your exterior walls. Not all buildings have this feature. Go outside and look up, you’ll see vinyl or aluminum siding panels anywhere from 6? to 12? or so. There should be perforations for every rafter bay or every foot or two. If you have soffits, but no perforations they can be modified easily. Keeping insulation in the attic from blocking airflow through soffits is addressed by using Styrofoam baffles.

Ridge vents are at the peak of your roof. The sheathing should have a gap 3? to 4? wide. This gap is covered with a breathable membrane or vented piece of aluminum or some other building material. The concept is air will enter the soffit vents and take the heat, moisture and any gases and take them out the ridge vent. This is considered passive ventilation. This is a principle we call the stack effect – think of how heat rises. Proper ventilation will reduce the heat in your attic space in the summer reducing your energy costs and extending the life of your sheathing and shingles. In winter, the lack of proper ventilation has the same ability to create mold growth and the need for mold remediation.

Gable vents are what you generally find on the sidewalls of your building. There is usually one on each side. The wind has to blow in the right direction for them to work well. It’s generally agreed that they are inadequate in performing as well as the combination of soffit and ridge vents.

Turbine vents are amazingly effective as they work off the slightest of breezes and use no energy other than what Mother Nature provides.

Powered fans are just what the name implies, they can be electric or solar which is obviously more energy efficient. Bathroom and dryer vents should never be vented into the attic, as this will create an ideal environment for mold growth. Exhausts should go through the roof to be vented to the outside.

Mold has everything it needs to grow in most buildings and when you add water vapor you complete the formula perfect for mold growth and then you’re looking at degradation of building materials, possible indoor air quality issues and the expense of mold remediation.

Craig Camel, Advanced Mold Diagnostics