Basement cold rooms were once a practical feature in many Canadian homes. Built for storage rather than comfort, they made sense at a time when basements weren’t meant to be lived in. Today, as more homeowners renovate their basements for usable space, cold rooms often become a problem rather than a benefit.
Understanding how a cold room works and why it causes moisture issues can help you decide whether to fix it, modify it, or remove it altogether.
What is a Cold Room?
A cold room, also known as a root cellar or cantina, is a small space typically located in a basement or beneath a front porch. Its purpose is simple: maintain a cooler, more humid environment than the rest of the home.
Traditionally, cold rooms were used to store potatoes, canned goods, wine, or garden bulbs. Because they rely on ground temperature rather than mechanical cooling, they offered a low-cost storage solution long before modern refrigeration became common.
How Does a Cold Room Work?
Cold rooms stay cool because they are partially or fully below ground and usually lack insulation. The surrounding soil naturally regulates temperature throughout the year.
Most cold rooms include a vent that allows outside air to circulate. This airflow helps keep temperatures low and supports humidity levels that extend the shelf life of stored items. When constructed properly, the room remains stable and functional without impacting the rest of the basement.
Why Does my Cold Room have Condensation?
Condensation is one of the most common issues with basement cold rooms. These spaces are typically built with unfinished concrete walls and floors. Concrete is porous, allowing moisture to pass through easily.
When warm air from the basement enters the cooler cold room, moisture in the air condenses on cold surfaces. Over time, this leads to damp walls, dripping water, and elevated humidity levels. If left unaddressed, condensation can quickly create ideal conditions for mold growth.
What are the Problem with Cold Rooms?
While cold rooms served a purpose decades ago, they often struggle to perform properly in modern homes. Two issues appear most often.
Mould Growth
Poor temperature control causes cold rooms to become too warm in summer and too cold in winter. This constant fluctuation leads to excessive moisture, surface condensation, and eventually mold. Once mold forms, it can spread beyond the cold room and affect the entire basement.
Not Deep Enough
Many cold rooms are not built deep enough below grade. Portions of the walls or ceiling may sit above ground level, exposing them to outdoor temperature changes. This creates a constant battle between cool soil temperatures and warmer exterior air, making stable conditions almost impossible to maintain.
How to Fix Your Cold Room
Cold room issues can often be corrected with proper insulation applied carefully and in the right locations. Over-insulating the space can raise temperatures too much, defeating the purpose of the room.
The most effective approach is to insulate the areas exposed above grade, such as the upper walls and ceiling. This allows the lower portion of the room to remain cooled naturally by the surrounding soil while reducing condensation risk.
How to Install Proper Insulation
Start with the ceiling, as this is usually the most exposed surface. Then insulate the upper sections of the interior walls down to the point where soil covers the exterior.
Leaving the lower portion of the walls uninsulated allows you to monitor temperature and humidity levels. Additional insulation can be added later if needed, depending on how the room performs throughout the year.
How to Get Rid of a Cold Room
Cold rooms often become a major obstacle during basement renovations. If moisture issues are not addressed properly, condensation and mold can spread quickly, sometimes within months, undoing renovation work and damaging finishes.
To eliminate a cold room, the space must be treated like the rest of the basement. This means sealing vents, insulating walls and ceilings, and stopping all air movement between the former cold room and the surrounding areas.
Leaving the room uninsulated or partially separated almost always leads to moisture problems.
Keeping a Functional Cold Room (If You Must)
If you need to keep a working cold room, several steps can reduce moisture risks:
- Ensure the room is properly insulated, especially above grade
- Use a fully insulated, sealed door with weatherstripping
- Install a vapour barrier on the warm side of insulation, including the ceiling
- Maintain adjustable ventilation so airflow can be controlled during extreme weather
Treating the cold room as if it were an exterior space helps contain moisture and protect the rest of the basement.
When to Call a Professional
Cold room issues are often tied to larger concerns, such as foundation cracks, moisture intrusion, or poor drainage. If you’re unsure whether to repair or remove a cold room, professional guidance can save time and prevent costly mistakes.
The team at GJ MacRae has worked with hundreds of basement cold rooms across the Greater Toronto Area. Whether the goal is correction or complete removal, our experience with interior waterproofing, exterior waterproofing, crack repair, and underpinning allows us to recommend the right solution for your home.
If your cold room is causing moisture problems or limiting your basement plans, getting expert advice is the best next step.
