You've survived the snowstorm of the century. Now get ready for the melt of the century.
Experts in home construction say most homes should be able to hold up under the strain of the region's recent snowfall with only minor damage, such as a shorn gutter or awning. The most likely source of trouble will come as the snow begins to melt, leading to leaky roofs and soggy basements.
"Because of standard construction techniques, I would not expect a problem for the average home from the snow load," said Stuart Chen, a civil engineering professor at the University of Buffalo in Buffalo, N.Y.
Even the most severe storms in Buffalo's notoriously snowy winters result in very few collapsed home roofs, he said. More likely is the collapse of sheds and carports that might not be built to the same standard, he said.
One exception is a split-level or other home style with multiple roofs of varying height. Often snow will blow off the higher roof onto the lower one, piling up to a potentially dangerous depth. Owners of these homes should be on the lookout for any unusual sagging and call an engineer or home inspector if trouble is suspected, Chen said.
Jerry and Judy Carrig were out early yesterday morning trying in vain to clear some of the snow from the porch roof of their Victorian home on Northern Parkway near Falls Road.
"We just tried pushing it off with a broom and a shovel," leaning out from the second story windows, said Judy Carrig. "It's too heavy! And the roof is too wide. So, even hanging out of the window, we can't get it."
A more common roof problem is an "ice dam." These typically form on the outer edge of a roof when the heat escaping through a roof melts the snow, sending water flowing down the slope. The water refreezes when it reaches an overhanging eve or gutter that extends beyond the warmth of the home. The result is a dam that forms a pool of backed-up water, which can seep under shingles and into interior ceilings and walls.
Experts caution against shoveling snow off roofs or hacking away the ice.
"Usually people will get up there and destroy their roof," said Frank Dumsha of Pasadena Roofing. "You might kill yourself, maybe knock your gutter down, tear your roof up. No, it's not a bright idea."
And don't bother calling him to do it for you.
"If somebody called me and asked me to do it, it's not likely I'd go on their roof and shovel their snow off," Dumsha said. "It's better to let it take its course. If something gets wrecked, that's what homeowners insurance is for."
A better response for rooftop snow is to increase the insulation on the attic floor and to uncover vents or even open attic windows to bring the interior temperature down, preventing the home's heat from melting the snow, said Jack Reilly, a Baltimore home inspector.
"Attics shouldn't be more than a few degrees warmer than the outside," he said.
Ice can also cause problems for basements.
The ground will remain frozen longer than the snow, causing the melt to puddle along the foundation and seep into cracks.
"When the thaw comes, everyone can expect to get some water in the basement," Reilly said.
Shoveling snow away from the foundation - where the heat of the house won't melt it - could prevent some of this damage so long as the ground is properly graded, he said.
Clearing the snow from gutter downspouts will help, too, he said.
Snow also needs to be promptly cleared from any vents or intakes.
Gas-fired artificial fireplaces, water heaters, and even high and medium-efficiency furnaces and water heaters operate with exterior vents that may be only a few feet from the ground, said Robert Dunlop, a principal with Carson, Dunlop & Associates consulting engineers in Toronto.
Older furnaces vent through roof-mounted chimneys. But even homes with older furnaces may have dryer vents close to the ground that should be cleared, especially if it is a gas dryer that is venting potentially hazardous exhaust, Dunlop said.
Newer furnaces shut themselves off when the vents are blocked and need to be restarted, he said.
"I've been fixing furnaces over the phone all morning," said Fred Needel, a Reisterstown heating contractor who began getting calls about the problem over the weekend as the snowdrifts piled up.
Electric heat pumps can also shut down if they become buried in snow. Most have a backup electric heater that kicks in when this happens, but it's expensive and inefficient to run, Needel said.
Rachael Simon, who lives in a rehabbed South Baltimore rowhouse with a rooftop deck that has a panoramic view of the Inner Harbor, found a good use for the snow.
"I'm kind of using it as a test," she said. "If [the deck] doesn't last the snow, it's not strong enough. I'd rather find out how strong it is with snow on it than with people up there."
Sun staff writers Mike Himowitz and Jennifer McMenamin contributed to this article.