It’s Late Summer—Time to Prevent Ice Dams on your Roof

ice dams on the roof of a house

The hot dog days of summer might not seem like the time to think about ice dams on your roof. But it is the time to think about roof maintenance that can keep these cold ridges from forming in the first place. Ice dams can cause major damage that can end up being both hazardous and expensive.

Ice dams are ridges of ice that form at the edge of the roof. Once formed, these ridges prevent snow from melting off the roof. Damage can be minor or can cause serious problems that require thousands of dollars to repair.

Causes of Ice Dams

Quick climate changes combined with insulation problems are the roof’s No. 1 enemies. In climates like Michigan’s,  a roof undergoes a series of rapid changes throughout the year. Ice and snow pound the roof, and branches made heavy by freezing rain can crash onto it. Melting snow runs through gutters and downspouts, only to re-freeze and thaw again. This cycle can cause gutter systems to break apart. Indoor heat can rise to the attic and warm the roof’s surface, adding to the weather’s natural freeze-thaw cycle.

The Science of How Ice Dams are Formed

Snow on the heated part of the roof melts and starts water flowing. When the weather turns cold again and the melted snow re-freezes on parts of the roof that are warmer than 32 degrees, it becomes an ice dam.

Ideally, every part of the roof should stay frozen unless outside forces add heat. Heat can escape from overhangs near where the exterior wall and the roof decking meet. This can be true especially in Cape Cod-style homes, where people live in the upstairs or attic rooms.

Maintenance to Prevent Ice Dams

Adding insulation to your home is the first choice in preventing ice dams. It’s best to add this insulation when installing a new roof, rather than waiting until after the roof has been installed. Waiting until later, or inheriting a poorly insulated home, often turns into a big and expensive job when the goal is to avoid ice dams. It can be difficult to access the areas where insulation is needed once the roof is already in place.

Clear downspouts and repair missing or lifted shingles to prevent ice dams from forming. Make sure the “drip edges” under the shingles and over the gutter are not bent. This is simple and inexpensive but can make a big difference once winter arrives.

Inspect and repair or replace ventilation grids and ridges. Ventilation should pull the heat out of the attic and let fresh air in. The attic temperature should be kept consistent. If this is not occurring, the roof will become warm in places where it shouldn’t and ice will start to form.

Building in Solutions During Roof Installation

Ice and water shields are products applied to the roof—usually when installing a new roof—that offer good protection from ice damage. The shield is a membrane installed under the shingles at the edge of the roof where a gutter might go. The material is very malleable and usually is installed similarly to the method used for applying rolled shingles. The membrane sticks to the roof and makes a great seal against water, even sealing where the nails are placed.

This is best applied when re-roofing a home, although existing shingles can be removed towards the bottom of the roof to apply the shield and then that portion of the roof can be re-shingled.

Snow guards for metal roofs. Snow guards are angular metal pieces that keep the snow from falling off the roof’s edge. While this helps protect anyone walking below a metal roof, it can also prevent ice dams from forming.

Consider roof slope when planning to build a new home. For best ice dam prevention, the roof should be flat enough to be walkable and the roof should not have a lot of valleys where snow can collect.

A Simple, Affordable Solution to Ice Dams . . . With Caution

Heat tape is another cost-effective solution to avoid ice dams on a roof. The tape is similar to a long cord that plugs into an electricity source.  The tape has a thermostat so that, when the temperature along the roof falls below freezing, the tape adds just a bit of warmth. This prevents the thaw-and-freeze cycle that could cause an ice dam to form. If you are a do-it-yourselfer, there are heat tape kits available at hardware stores that include the tape, metal clips and instructions for installing the tape to your roof.

A word of caution about heat tape. Its use has been known to cause fires on occasion. Some tips to keep heat tape safer include:

  •  Purchase UL- or CSA-certified heat tape. Look at the package!
  •  Be sure that the tape has a grounded, three-prong plug.
  •  Only use heat tape for the purpose it is intended. For example, some tape is intended for roofs, while others are intended for pipes.
  •  Ensure the heat tape is plugged into a grounded (GFCI) outlet.
  •  Do not wrap heat tape over itself.
  •  Inspect the heat tape before the winter and remove it if you see cracks, bare wires, or any other sign of deterioration.

Using heat tape to prevent ice dams may be the easier and least expensive of the options, but being vigilant to avoid a fire is necessary if you install it on your roof.

Summing it up

Ice dams are formed by continuous freezing and thawing of both roof materials and the elements, combined with a poorly insulated or poorly ventilated attic. Protecting your home against ice dams on your roof requires fixing the source of the problem and proper maintenance. To help even more, manufacturers have also created ice and water shields that are pliable, stick to roofs and create a seal against water. They are easily installed when installing a new roof. Finally, heat tape is sometimes installed on the roof itself and plugged in when conditions for ice dam creation are ideal. While effective, heat tape has also caused fires so caution is of utmost importance.

If you have experienced ice dams on your roof and would like to prevent them this winter, feel free to contact Melvin Belk Roofing. As a Michigan roofer for over 40 years, we know the climate and have helped thousands of homeowners resolve their ice dam issue once and for all. Contact us now for a free consultation—before winter gets here!!