🏗️ Typical locations
Balcony slabs continuous with the floor slab, reinforced-concrete columns, parapet ring beams, window reveals, wall-ceiling junctions. Every spot where unclad concrete is exposed to the cold.
Thermal Bridges: The Invisible Energy Leak Points in Buildings
A house may have excellent wall insulation, but if balconies, columns and ring beams remain "bare," heat rushes to escape through those very spots. These "hidden pathways" are called thermal bridges - and they are the number-one culprit for mould, cold spots and unexplainedly high bills.
1. What Are Thermal Bridges?
Imagine wearing a warm down jacket but with bare arms. Heat escapes precisely from there. In a building, the "bare arms" are columns, beams, ring beams and balconies - which are typically not wrapped in insulation in conventional construction.
📐 Ψ-Value (Linear coefficient)
A thermal bridge is measured in W/(mK). An unbroken balcony: Ψ = 0.80 – 0.90. With Isokorb: Ψ = 0.05. The difference in annual losses is enormous.
🌡️ Thermal camera reveals all
An IR thermal camera photographs the building and shows in red-yellow colours exactly where heat is escaping. Balconies "glow" like energy-wasting light bulbs.
💸 Hidden cost
Thermal bridges can increase a building's total consumption by 20-30%. You pay for electricity or oil for heat that never stays in the room - it escapes through bare structural elements.
2. Mould & Moisture: The Visible Consequence
Many homeowners see black mould in ceiling corners or behind wardrobes and assume "water is leaking in." In reality, mould in typical Greek buildings is almost always caused by thermal bridges.
💧 Dew point
The warm room air carries moisture. When it hits a frozen corner (thermal bridge), it cools below the dew point. Water vapour turns into droplets - the perfect "food" for mould.
🦠 Health hazards
Mould spores float in the air and cause allergic reactions, respiratory problems, and in severe cases chronic asthma. In homes with young children or elderly residents, the risk is even greater.
🔁 Vicious cycle
The owner cleans the mould with bleach, but within two weeks it reappears. Why? The cause (the frozen column or ring beam) remains. The only solution is external insulation of that spot.
🏚️ Building damage
Beyond health, chronic moisture damages plaster, turns walls grey, and can even corrode the reinforcing steel in the concrete - undermining structural integrity.
3. Solutions in New Construction
In new buildings (or full reconstructions), the engineer can design an uninterrupted insulating envelope, with no concrete spot left "bare" to the cold.
🧊 Thermal-break elements (Isokorb)
Special elements cast inside the concrete during pouring. They "cut" the thermal bridge by 90% while maintaining full structural capacity. The cleanest solution.
🏗️ Passive design
Reducing or eliminating protruding balconies. Instead of external slabs, loggias (recesses) within the envelope are designed - with zero thermal bridges.
📐 Continuous ETICS
External insulation hugs every structural element with no "gaps." Columns, beams, ring beams - all are wrapped in insulation. The most effective large-scale solution.
📊 Result
A new building without thermal bridges needs 15-25% fewer kW of heating, never develops mould, and ensures uniform temperature on every interior surface.
4. Solutions in Existing Buildings (Renovation)
In an existing building, installing Isokorb on balconies is practically impossible without demolition. But there are alternative solutions that drastically reduce losses.
🧱 Balcony "wrapping"
The balcony slab is wrapped with EPS or mineral wool on top and underneath. It doesn't eliminate the bridge 100%, but reduces it by 50-60%.
🔲 Window reveal insulation
Window reveals (recesses) are hidden thermal bridges. Installing thin insulation (2-3 cm) internally or externally at the reveals significantly reduces local losses.
🏠 ETICS as a priority
External insulation (ETICS) automatically "wraps" columns, beams and ring beams. If you can't fit Isokorb, a full ETICS system eliminates most thermal bridges without any structural intervention.
💡 Thermal camera first!
Before deciding, request a thermographic survey of the building. It reveals exactly where heat is escaping, so you can focus on the highest-return spots - without wasted money.
🏗️ Thermal bridges are invisible, but costly. Every "bare" column, every uninsulated balcony is an invisible bill you pay every month. External insulation and thermal-break elements erase these "ghosts" forever.
Related Articles
External vs Internal Insulation: Thermal Mass Passive House (Passivhaus): The 5 Core Principles The Envelope & Passive Buildings (Passivhaus) Building Airtightness & Blower Door Test
Energy Design, Studies & Legislation
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