Protect gutters from snow and ice damage

January 08, 2010|By Mike McClintock | Special to the Tribune

Gutters are a necessary evil. They keep water away from the foundation and are often the main reason that basements stay dry. But if it's not a clog of twigs and leaves in the fall, it's a bottleneck of snow and ice in the winter.

To keep the system clear, you can clean out debris before the snow hits. Even then, an overload of ice and snow can choke the system, and form ice dams that back up under shingles and leak into the house.

To defeat that threat, homeowners often take extreme measures, before and after a winter storm, although many of them make things worse instead of better.

Gutters look right installed in a level line that matches the line of the roof edge. But to encourage drainage, the rule of thumb is to create a slope in gutters of about one inch per 10 linear feet. That means the trough should drop six inches end to end on a 60-foot-long house. But the fascia board along the roof edge on many houses is not deep enough to accommodate that drop. The better solution is to split the run, and the slope, in half by establishing a high point in the middle of the run and sloping the gutter away in both directions.

Seamless gutter contractors can fabricate almost any length in one piece, right off their trucks. That eliminates potential leaks at seams, but not necessarily the number of outlets for downspouts. On long runs, another rule of thumb for gutters is to provide an outlet every 35 feet. Downspouts can be cumbersome details with offset fittings and leaders cluttering up the house facade. But a short run to an outlet is less likely to freeze than a long one. And in case one outlet becomes blocked, at least some of the water that backs up can flow out the other end.

If there's a break in the weather, warmer temperatures and full sun may do the job, though gradually. Trying to hurry the process with hot water doesn't work. Even boiling water from a kettle has little effect on a mass of ice along the roof edge. Establish a bucket brigade coming direct from the stove, and at some point -- in the gutter or downspout -- the steaming water will turn cold and add to the buildup. The melt can work into every nook and cranny of the gutter system, back up under shingles, seep behind fascia boards, drain into soffits at the roof overhang, and may burst leaders, elbows and other fittings as it freezes.

Torch melting seems to make more sense because it doesn't add water. But a typical homeowner's propane torch heats only a small area. (It's main use is soldering joints in copper pipe -- an area about the size of your thumb.) And when the pinpoint flame melts a small amount of ice, the water runs and quickly freezes again down the line. On some roofs, particularly modified bitumen often used on flat and low-slopes that collect the most ice, a torch can set the roof on fire. It sounds crazy in all that ice and snow, but the rubberized roofing is flammable. There are many cases of accidental fires during installation by professional roofers without the fire-stopping help of melting ice nearby.

Ice clings along roof edges and gutters, where using enough force to break it is likely to break whatever is underneath. Sharp or pointed tools that can fracture ice are likely to puncture the roof. Then you have a leak just waiting for the ice to melt. Break off a chunk along a roof edge, and you may twist open metal flashing, creating another leak source. Shoveling loose snow will help, if you can do it safely. (I use a long-handled snow rake on the eaves at my house, working from the ground.) But clearing the roof edge helps. It removes snow that acts as an insulating blanket, preserving ice blockages underneath by shielding them from warmer temperatures and sunlight.

When clear gutters still don't drain freely, the problem is almost always in the offset fitting that carries water from the roof edge to the downspout against the house. Its S-shape is a built in bottleneck. A plumbing snake may clear a blockage. If not, you have to take apart the downspout to get at the obstruction.