An ice dam is a ridge made of ice that forms at the roof’s edge, which can pose a number of problems to your roof. In today’s post, the roofing and siding contractors at Allstar Construction share a look at what causes ice damming, and how proper roofing insulation can help prevent it.
How Do Ice Dams Form?
A poorly-ventilated attic may trap warm air coming from the indoor living spaces. If the roof deck lacks insulation or is poorly insulated, the warm air in the attic will raise the roof temperature to above freezing and melt the snow on the top of the roof. The meltwater running towards the roof edge would refreeze. More meltwater would eventually form an ice dam. Meltwater that drips over the roof edge would later form icicles.
The Dangers of Ice Damming
An ice dam can cause moisture to infiltrate the roof deck through the roof’s edges. This can lead to moisture damage that could result in delaminated decking, wood root, and mold growth, many of which can happen unnoticed until it’s too late. Also, moisture in the attic can cause damage to attic insulation, as most types of insulation tend to form clumps when in contact with moisture. Icicles may also cause injuries if they break off while someone happens to be standing underneath.
How to Prevent Ice Damming
Roof repair companies recommend improving the insulation in the attic to prevent ice damming, as well as addressing ventilation issues. Some attics only have insulation on the attic floor, either loosely strewn on the floor or tucked under the boards. Applying cellulose or expanding foam insulation under the roof deck can help slow down thermal transfer through the roof and stop the snow on the rooftop from melting.
Just as important is having a proper roof ventilation system. Vents located at the roof ridges utilize the natural rising movement of warm air to vent it out of the attic. This creates negative pressure that pulls fresh air through the intake vents located at the lowest point of the roof, usually at the soffits. Your roofing contractor can correct poor ventilation by adding ridge vents and making sure it is proportionally sized with the intake vents. Exhaust fans can also be installed to supplement the ridge vents.
Allstar Construction is the leading provider of water and fire restoration services serving the Twin Cities metro area. Give us a call at (763) 479-8700 or fill out our contact form to schedule an appointment.