Basement Mold in Rochester

Frozen ground is the whole story

In summer, rain soaks into the soil around your house and keeps moving down. In late winter the top layer of that soil is frozen solid, so meltwater cannot go down. It runs sideways instead, along the surface, until it reaches the lowest available point - which, for most houses, is the backfilled trench against the foundation where the soil is looser than the ground around it.

That trench acts like a bathtub. Water sits against the wall under pressure, and masonry that would happily shed a rain shower cannot hold back standing water for weeks.

What the age of the house does

Much of Rochester's stock went up before 1940. Those foundations were built with the assumption that a basement would be damp and used for coal, storage and a furnace - not for a carpeted family room. They generally have no exterior waterproofing membrane, no interior vapour barrier, and mortar joints that have had eighty winters to open up.

None of that is a defect. It becomes a problem only when someone finishes the space, which puts organic material - paper-faced drywall, wood framing, carpet - flat against a wall that was always going to be damp in spring.

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It is common for a contractor to look at those five things and conclude that a $200 downspout extension is doing more for you than a $4,000 interior drainage system would. A contractor who never mentions them is one to be careful with.

When interior drainage is genuinely the answer

Sometimes the water table is simply high, the lot slopes towards the house, or the neighbouring property drains onto yours. In those cases surface fixes will not do it, and an interior perimeter drain to a sump is a reasonable investment. It is also a significant one, and worth two or three quotes.

Common questions