Overlay vs Screed Underfloor Heating: Full Comparison

Which system is right for your project? A clear and honest breakdown.

When choosing underfloor heating, one of the first big decisions is whether to go for a **screed system** or an **overlay system**. Both can deliver excellent results, but they suit different situations.

Screed Systems

In a screed system, the heating pipes are embedded in a layer of concrete or liquid screed. This is the most common approach in new builds and major renovations.

Advantages

  • • Excellent thermal mass – stores and releases heat evenly
  • • Generally the lowest cost per m²
  • • Very durable and long-lasting
  • • Works well with most floor finishes
  • • Best performance when paired with a heat pump

Disadvantages

  • • Requires significant floor build-up
  • • Longer installation and drying times
  • • More disruptive (especially in renovations)
  • • Not suitable if you want to keep existing floors

Overlay Systems

Overlay systems are laid on top of an existing solid floor. They are popular in renovations because they cause less disruption and have a much lower build-up height.

Advantages

  • • Low floor height increase
  • • Faster installation with less disruption
  • • Good performance with modern low-profile systems
  • • Suitable when you want to keep existing floor levels

Disadvantages

  • • Usually higher cost per square metre
  • • Slightly less thermal mass than screed systems
  • • Performance can vary between different overlay products

Quick Comparison

Factor Screed System Overlay System
Best For New builds & major renovations Renovations & existing solid floors
Floor Height Increase Higher Low to medium
Installation Time Longer (including drying time) Faster
Cost per m² Usually lower Usually higher
Thermal Mass Excellent Good
Disruption Higher Lower

Which Should You Choose?

Choose Screed if:

  • • You’re building new or doing a major renovation
  • • You want maximum thermal mass and even heat
  • • Budget per square metre is important
  • • You’re happy with longer installation times

Choose Overlay if:

  • • You’re renovating and want to minimise disruption
  • • You need to keep floor levels low
  • • You want a faster installation
  • • You’re working with existing solid floors

Not sure which system is right for your project?

Use our Underfloor Heating Calculator to get personalised recommendations based on your floor type.

Open the Underfloor Heating Calculator Try the Combined Estimator

Related Articles

→ Best Underfloor Heating System for Renovations → Underfloor Heating Costs in Devon & Cornwall 2026 → Underfloor Heating for Renovations → Heat Pump + Underfloor Heating: Is It Worth It?