Coldrooms and Condensation - Causes and How to Fix It

Condensation occurs when warm, moist air comes into contact with a colder surface, like a coldroom door, frame or panel. It's one of the most common problems in commercial refrigeration and if left untreated can lead to mould, ice build-up, structural damage and health and safety issues.

When does condensation occur?

The problem is most common in winter when the temperature difference between inside and outside is at its greatest. But condensation can also occur in spring and summer depending on the location, temperature and humidity around your coldroom.

When the dew point of the surrounding air is higher than the surface temperature of your coldroom door or frame, moisture builds up. This is most noticeable in unheated warehouses and buildings where there is little air movement.

Some condensation is normal and not necessarily a problem. Excess condensation, particularly pooling water or visible mould needs to be addressed promptly.

Common causes

• Damaged or missing door seals - the most frequent cause
• Poor strike alignment - door not sealing tightly when closed
• Inadequate or failed insulation in the panels
• Thermal bridging through the frame or structure
• Failed or missing door frame heaters
• Lack of ventilation or air movement around the room
• Voids at the side or rear of the room where damp air becomes trapped

Frost, ice and what they tell you

Frost and ice on coldroom doors and frames are not the same problem and it's important to understand the difference.

Frost is usually a sign of air ingress - warm moist air is getting into the room through a gap in the door seal or frame and freezing on contact with the cold surface. The fix is typically a new door seal or strike plate adjustment.

Ice build-up - particularly on the door frame itself, is more often caused by thermal bridging or condensation that has frozen. When the frame gets cold enough, moisture in the air freezes directly onto it rather than dripping away. This is where door frame heaters play a critical role. A failed or missing frame heater allows the frame temperature to drop below the dew point, causing ice to build up rapidly.

If you're seeing ice on your door frame, check the frame heater first. A failed heater is a straightforward fix - replacing it will often solve the problem completely.

Dual compartment rooms and partition walls

Ice and condensation problems are particularly common in dual compartment coldrooms — where two temperature zones share a partition wall. If the partition wall isn't installed correctly, with proper insulation and no thermal breaks, condensation forms on the warmer side of the wall and can freeze.

This is a frequently overlooked issue during installation and can be difficult to diagnose after the fact. If you're experiencing persistent ice or condensation on an internal partition wall, the installation detail needs to be investigated.

Failed insulation - the hidden problem

One of the most common faults we see in older coldrooms is failed panel insulation. When insulation breaks down, condensation forms on top of the ceiling panels and freezes. The freeze and thaw cycle repeats - and over time moisture builds up inside the panel until it eventually drips through.

The reported fault is almost always a water leak through the ceiling. In most cases it isn't a leak at all - it's condensation caused by insulation failure. If you're seeing water dripping from ceiling panels, get a professional to assess the insulation before assuming there's a plumbing problem.

Many coldrooms are installed outdoors with corrugated roofing overhead for weather protection. With fluctuating temperatures and weather conditions, condensation can form more readily in these situations if ventilation isn't adequate.

The importance of air gaps

A correctly installed coldroom should have a clear air gap around all sides - between the panels and the surrounding walls, floor and ceiling. This allows air to circulate freely and prevents moisture becoming trapped. We recommend a minimum gap of 50mm, but the larger the better.

When coldrooms are installed tight against walls with no clearance, warm moist air becomes trapped in the void behind the panels. With nowhere to go, it condenses on the cold surface and runs down to the lowest point - usually appearing as pooling water on the floor nearby.

If you're having a new coldroom installed, always ensure adequate clearance is built in on all sides. For existing rooms with no air gap, improving ventilation or extraction around the perimeter is the most effective solution.

Where to start with an existing problem

The first thing to check is always the door seal. A damaged or poorly fitted gasket allows warm air in and cold air out - creating the perfect conditions for condensation. Next check the door handle strike - if the door isn't pulling tight against the seal when closed, a simple strike plate adjustment can make an immediate difference.

Pooling water on the floor

If you're finding water pooling near the coldroom, it's often not coming from the door at all. In our experience this is usually condensation forming on the coldroom wall inside a void at the side or rear of the room, then running to the lowest point. Improving ventilation or extraction in that area keeps air moving and prevents moisture building up.

When to call a professional

If condensation is coming from within the panels themselves, you're seeing water dripping from the ceiling, or you have persistent ice build-up on door frames or partition walls, these all point to issues that need a professional assessment. Get in touch with our team if you're unsure what you're dealing with.