Freeze and Thaw of Winter Can Cause Problems for Your Roof

It’s been a crazy winter!  And we still have two months to go. Have you noticed all the potholes on the roads? Well, obviously, the potholes are the result of the freeze/thaw we have been going through.  The rapid swings in temperature can wreak havoc on the asphalt roads and cause them to fail.

imagesCA630XEYWhat’s the next biggest asphalt thing in your life?  It’s your roof.  Every time you see or don’t see and hit a pothole, think about your roof.  It might be worth the preventive maintenance to have a professional get up there and take a close look.  The continual heating/cooling can cause ice dams which occur when accumulated snow on a sloping roof melts and flows down the roof until it reaches an area cold enough and then refreezes, typically at the eaves. The ice formed in such a way often grows and “backs-up” the roof pushing its way under the shingles and damaging everything in its path. This is a situation that you want to identify early.

If you have a professional look at your roof and need to make repairs or replace your roof choose your installer very carefully.  A roof that is installed improperly will not be covered by a manufacturer’s warranty. Make sure you choose an installer who not only is very experienced but is also credentialed by the manufacturer whose product they install. Very often you can find credentialed contractors at the manufacturer’s website. While there, why not also look for contractors who participate in “take-back” programs to divert your old roof from going into a landfill.

Remember, whether you dodge or ford those potholes, they might actually be doing you a favor by reminding you to think about your roof.

Proper Roof Ventilation is Critical

Lucas Hamilton

I was in Pittsburgh recently and had the pleasure of visiting a home that was about to be reroofed again – it has been reroofed several times in the last few years.  The house was between 30 – 40 years old and originally had wood shakes which were replaced with asphalt shingles.  The roof was under ventilated to begin with but when they went to the new system it made the problem worse. Each contractor that came along tried to do different things to deal with the problem that the homeowner was encountering.

While putting away Christmas decorations a few years ago, the homeowners noticed ice forming in her attic.  Originally, they thought it was from a roof leak so they replaced the roof.  However, the next winter the ice returned. The roof leak wasn’t the cause. It was insufficient attic ventilation. The house had a great deal of moisture build up in the attic space which was causing ice to form in the winter on the underside of the roof. 

The second contractor tried to add roof ventilation but did it in a way that didn’t help the situation.  He installed a power vent up high on the roof next to the ridge vent.  They put a humidistat on the power vent to activate the vent when the humidity rose in the attic.  The problem was that when the power vent kicked on, because of its position next to the ridge vent, it was pulling air in through the ridge vent and right out through the power vent which did not correct the humidity in the attic or solve the ventilation issue.

I met with them to discuss what was happening to the roof, make recommendations and work with the roofer to correct the ventilation issue. The roofer is going to optimize the power venting and eliminate the ridge vent. This was chosen because there is a concern that with the shape of the roof, you may never get sufficient soffit intake for the ridge vent alone to be sufficient.

As a result of the moisture in the attic, mold was developing on the roof decking.  While there are many ways to remediate mold, the homeowners wanted to take the most certain route which is to remove the contaminated wood. Of course, that adds cost to the project but is the best method of remediation.

Even though the knowledge base on ventilating residential roofs has expanded tremendously over the past 50 years,  professionals can sometimes have a difficult time properly ventilating a unique or challenging roof.  The homeowners were frustrated because they received different information from each contractor.  That can happen.

It is always a good idea to research the issues and ask questions.  In buildings where the attic ventilation requirements are not straight-forward the professional needs to look at the situation  from many angles to come to the right conclusion that solves the problem.   

Lucas Hamilton is Manager, Building Science Applications at CertainTeed Corporation

Rough Winter Has Been Hard on Roofs

If you’re like me, you’re still cleaning up from one of the roughest winters in memory, particularly here in the Northeast. Not only did landscaping and trees take the brunt of record snowfall, but the outsides of our homes took a beating as well, wreaking havoc on roofs.

Why am I talking about snow and ice during the spring? This is one of the biggest home improvement times of the year and chances are a number of roofs will need to either be repaired or replaced due to ice dams.

As a result of the constant freezing and thawing many roofs were subjected to ice dams. Ice dams are formed when heat from the inside of a home escapes into the attic and warms the roof decking during the winter. This heat, combined with heat from the sun, can melt snow on the roof. Melting snow then runs down toward the eaves as water. When it reaches the cold eaves and gutters it refreezes. This continual thaw and re-freeze process creates ice dams. The result is water can back up under the roof shingles where it can soak through the roof decking or wall sheathing, causing damage to attics, ceilings and walls. Ice dams make for some incredible icicles off the gutters, but the damage can be severe.

There are three ways to defend against the damage ice dams cause:

Attic Insulation - Insulation keeps heat from escaping from your home’s living space into your attic. You can add insulation batts or blown-in insulation to improve attic insulation. If the home was built before 1980 chances are that more attic insulation is needed.

• Attic Ventilation System – Unchecked moisture can promote mold, mildew, and wood rot. Natural or static ventilation systems consist of simple vent or covered openings in your attic. These are typically ridge vents, gable, eave, or roof vents. Many ventilation experts agree that externally baffled ridge vents combined with vented soffits are a very effective method for ventilating an attic.

Water-proofing shingle underlayment – This is only an option if the roof needs to be replaced. While water-proofing underlayment does not prevent the formation of ice dams, it will prevent backed up water from getting into the house in those roof areas where it is applied.

Making changes to prevent the occurrence of ice dams is critical for the health of the home and its energy efficiency. An unprotected roof is an ice dam crisis waiting to happen.