Basement and Foundation Waterproofing

Stopping water before it reaches your basement

Exterior waterproofing means excavating the wall down to the footing, cleaning the concrete, and applying a waterproofing membrane that bonds to the wall and stays flexible — so it does not crack as the foundation moves or settles over time. Over the membrane, a drainage board (a dimpled sheet) creates an air gap between the soil and the wall, which breaks hydrostatic pressure and lets any water that reaches the wall run straight down to the perimeter drain instead of being forced through the membrane.

This is the system that keeps a basement dry from the wall side. Combined with a functioning perimeter drain at the footing, it addresses both ways water enters — through the wall and from below.

Exterior vs. interior waterproofing

Exterior waterproofing stops water before it enters the wall. Interior waterproofing manages water after it has already come through — typically an interior perimeter channel at the base of the wall that collects water and routes it to a sump pump. Interior systems are less disruptive to install (no exterior excavation) and can be the right choice where exterior access is impossible — a shared wall, a deck, or a finished landscape you cannot dig up.

The honest difference: exterior waterproofing is a permanent fix that stops water at the source. Interior waterproofing is water management — it lets water in and pumps it out. For a finished basement, exterior is the better long-term investment. For an unfinished basement where excavation is not practical, an interior system is a legitimate alternative. We assess the property and give you a straight comparison rather than pushing one approach.

Cracks, cold joints, and the details that matter

Water does not need a large opening to enter a foundation. A hairline crack in a poured concrete wall, a cold joint where two pours meet, or a form-tie hole can all let water through under hydrostatic pressure. For isolated cracks, polyurethane or epoxy injection can seal the crack from inside the wall without excavation — a targeted fix that works when the rest of the wall is sound. When the waterproofing has failed along a section of wall, or there are multiple cracks, a section excavation to re-waterproof that stretch is the lasting fix.

We do not recommend excavating a whole wall when one crack is the problem, and we do not recommend injecting a crack when the waterproofing around it has failed. The inspection tells us which approach matches the actual condition.

A dry basement starts with understanding where the water comes from

Waterproofing and drainage are two halves of the same system, and a basement that stays dry has both working. If only one has failed, you fix that one. If both have failed — common in homes 50 or more years old — you address both, and the order and scope depend on what the inspection shows. We will not sell you a full waterproofing job if the problem is the perimeter drain, and we will not tell you a new drain will fix a wall that is leaking through cracks. The diagnosis comes first.