What's Under the Roof?

I recently did work for a homeowner who got the shock of her life when we removed her old roof and found sheet after sheet of black, rotten plywood. The homeowner couldn’t believe it and asked me how the plywood could be so damaged if she had never had a roof leak. 

The answer is quite simple and a lot more common than you think. In our area of Connecticut, nearly all attics don’t have enough insulation and aren’t ventilated properly. I meet people who need a new roof and want me to just lay an extra layer of shingles over top of what they already have to save money. What they don’t realize is how much deterioration exists that they simply can’t see.

With a roof, airflow is absolutely crucial. Attic ventilation allows your home to “breathe” by taking in air from the outside and letting out air from the inside. Too many homes that I work in aren’t properly ventilated, in fact, most have their bathroom and even dryer vents going into the attic instead of outside. In order to have proper ventilation, your home needs a system that includes intake ventilation through the soffit or a new product called SmartVent which is installed on top of the roof near the gutter edge. Louver vents were typically used at an exhaust vent in the 1950’s and 1960’s but now ridge vents are more common. If your house has both louver vents and ridge vents, the louver vents should remain closed, otherwise, the louver will act as an intake vent and will only cool the top third of the attic. 

In the colder months, it’s not uncommon for me to see frost on attic plywood because of subpar insulation. Insulation and ventilation work hand in hand - the ventilation controls the airflow and the insulation controls the temperature. You’re probably familiar with insulation - it’s a cotton-looking fiberglass material that often comes in pink or yellow rolls. It can also be loose-filled into tough to reach areas with a blowing machine. Remodeling professionals use insulation between walls, in attics and in basements to retain heat in the house in the winter and keep it cooler in the summer. However, without proper ventilation, the insulation is just as susceptible to moisture and deterioration as the plywood.

My customer didn’t venture into her attic, so she never noticed the problem. What she thought was a simple roof replacement ended up being a bigger job simply because after years of decay, the plywood she had was no longer strong enough to properly support the new roof. Ignoring the problem would have voided the new roof’s 30-year warranty.

The lesson for this week? If you’re going to reroof your home, make sure that the plywood is healthy and that your contractor has given you a thorough plan to ensure that your home is properly insulated and ventilated. It might cost a bit more today, but it will regulate the heat and cooling in your home for years to come, saving you on energy costs and giving you more comfort as well as peace of mind for the health of your house.

Bob O'Donnell is the owner of O'Donnell Bros, Inc., a Bristol-based home improvement company established in 1975. Email your questions for Bob to info@odonnellbros.com with the subject line “Ask the Pro”. All questions may be considered for publication. To contact Bob for your remodeling needs, call O'Donnell Bros, Inc. at (860) 589-5155 or visit www.odonnellbros.com. Advice is for guidance only.

Let Your Home Breathe with Proper Attic Ventilation

Last week we talked about how poor ventilation can cause frost and icicles inside the attic and dangerous ice dams outside at the base of the roof. These warning signs should set off alarm bells for homeowners as they can lead to major leaks and expensive damage to shingles, walls, and insulation. So let’s take a look at how to mitigate any potential problems with a quick crash course on attic ventilation.

An attic that’s well ventilated will reduce heat build-up in the summer and allow moist, warm air to escape the house in the winter. A house that can “breathe” properly is more energy efficient, keeps the home dry, and reduces the potential for ice build-up in the winter.

Have a look at your roof. Do you see any vents under the eaves, at the top of the gable or along the ridge? Some vents can be tough to spot, so if you’re unsure, think back to our recent winter storms. Did the cold temperatures result in a build up of thick ice near your gutters? If so, this is a telltale sign that your home isn’t properly ventilated. You can also check by grabbing a flashlight and heading up into the attic. If you see dampness, frost, or icicles, it means you have a ventilation problem. In the summer, just simply touching the ceiling can tell you if your vents aren’t adequate. If the ceiling feels hot, your attic is effectively acting like a solar panel, increasing your cooling bills by trapping hot air that can’t escape.

Proper ventilation works as a system with different vents controlling air intake and exhaust. As heat escapes the main living area of the house, a correct system will allow that air to flow through the attic instead of getting trapped inside it. It works like this. Escaping air from the main living space of the home will flow through a soffit vent at the base of the roof near the gutters and along the underside of the eave. As this air enters the attic, it rises up and will then look to exit, which will often be through a gable vent or a ridge vent at the very top of the roof. If the air is flowing properly, the attic will stay cool and dry and you won’t have to worry about those dreaded ice dams.

So how do you know how many vents you need for your home? Ventilation is determined by area, so start by figuring out the square footage of your attic. For example, a 30-foot x 50-foot attic would equal 1,500 square feet. Professional contractors estimate about one square foot of vent opening for every 150 square feet of attic area as per Connecticut building codes, so in this case, you’d be looking at 10 square feet of total vent area. Each vent will come with a net free vent area (NFTA) measurement to help you calculate your vent size, and the total area should be split evenly between intake and exhaust vents. Remember that vents need to be free and clear in order to work properly, so if you feel like you have enough vents but are still having issues with airflow, make sure to check that they aren’t being blocked by insulation or accidently covered over.

Have a question about ventilation, insulation or roofing? Feel free to shoot me a message on Facebook at www.facebook.com/odonnellbros.

Bob O’Donnell is the owner of O’Donnell Bros. Inc., a Bristol-based home improvement company established in 1975. Email your questions for Bob to info@odonnellbros.com with the subject line “Ask the Pro.” All questions may be considered for publication. To contact Bob for your remodeling needs, call O’Donnell Bros. Inc. at (860) 589-5155 or visit www.odonnellbros.com. Advice is for guidance only.