The recent weather has had some unexpected consequences for many homeowners here. Water has leaked through normally sound roofs and into basements that are usually dry. The leaks stopped as the snow and ice disappeared, and they may not recur for a long time.
These particular leaks followed a freeze thaw sequence that froze the ground surface, deposited a layer of snow and ice than thawed selectively to yield little ponds of water restrained from flowing away by ice dams or frozen ground.
Take the roof situation, for example. Snow and sleet collected all over the roof. Temperatures then allowed the snow to melt on the upper portions, but to ice up in gutters and downspouts and on the overhangs. The melting water running down from above was restrained by these ice dams and collected pools.
Most suburban roofs are covered with shingles or slate that shed water normally but are not waterproof. Standing water can leak through. Usually the result is water dripping through the exterior overhang, less often into the exterior wall, showing up at windows and other discontinuties, occasionally on onto the interior of the house.
Shallow, sloped roofs are more prones to this problem than steep roofs. To prevent it, heater cables are laid in the guttering, and perhaps part way up the roof, and are energized as soon as the freezing starts.
The basement leaks result when a bit of thawing allows melted water (from the roof or elsewhere) to pool on the frozen ground adjacent to the foundation walls. The water has nowhere to go but into the house because it can't percolate into the frozen ground or flow away because of blocking ice dams.
About all the home-owner can do is to reach for a mop and bucket. A bit of snow shoveling and ice breaking outdoors might also help, especially if a downhill path can be made to allow the pool to drain away from the house.
Walker is president of Claxton Walker & Associates, a home inspection firm, and Papian is the chief engineer.