Across southern England — from Hampshire, Surrey, Sussex, Kent, Oxfordshire, Berkshire to Wiltshire — many period homes still have suspended timber floors. Beautiful? Absolutely. But they’re also prone to cold, draughty floors and high heating bills. With energy costs up and EPC ratings under the microscope, upgrading underfloor insulation is one of the smartest ways to boost comfort and efficiency.
Actis Hybris is our go-to for suspended floors. As a multi-foil, honeycomb insulation, it delivers excellent thermal performance, handles moisture sensibly, and fits neatly between uneven joists. Installed by Carbon Zero Solutions Ltd (The Insulation Guys), it turns cold floors into warm, efficient living spaces — fast.
How Suspended Floors Leak Heat
Suspended timber floors sit above a ventilated void. That airflow prevents rising damp — but it also carries away heat, causing:
- Cold floors and uneven room temperatures
- Higher heating demand (and bills)
- Risk of condensation and moisture issues in the sub-floor void
- Lower EPC ratings and buyer confidence
Traditional Options vs a Modern Alternative
Two common legacy choices are:
- Wool (glass/sheep’s wool): reasonable thermal values, but can sag, absorb moisture, and lose effectiveness.
- PIR boards (Celotex/Kingspan): good thermal resistance, but rigid, moisture-sensitive, and fiddly to fit between uneven joists.
The modern upgrade is Actis Hybris — lightweight, flexible, breathable, and engineered for real-world floors.
| Feature | Wool | PIR Board | Actis Hybris |
|---|---|---|---|
| Thermal performance | Moderate | High | Very high – multi-foil cells limit conduction, convection & radiation |
| Moisture behaviour | Can absorb moisture | Can trap condensation | Breathable – balances vapour movement; keeps joists healthy |
| Install in uneven joists | Messy & time-consuming | Awkward; edge gaps likely | Flexible fit; quick, clean, consistent |
| Longevity | May slump over time | Rigid; can gap or bow | Keeps shape and performance for the long term |
| Eco profile | Mixed | Higher embodied carbon | Low-carbon, recyclable materials |
Why Breathability Matters in Southern England
Our mild, damp climate means moisture control is critical under suspended floors. Wool can hold moisture; PIR can trap it. Hybris allows controlled vapour diffusion, reducing condensation risk and protecting timbers — ideal for heritage homes from Winchester to Canterbury.
Our Installation Approach
- Survey the sub-floor void and ventilation routes
- Install Hybris neatly between joists; seal and detail edges
- Where useful, pair with Knauf mineral wool in other zones for a balanced whole-house approach
- Document before/after for EPC evidence and buyer confidence (see our 2025 Insulation Guide)
Efficiency, Comfort & EPC Gains
Clients in Hampshire, Surrey and Sussex report dramatically warmer floors and lower heating demand. Pairing floor upgrades with roof/loft improvements can support EPC band lifts (see: How to Improve Your EPC Rating in 2025).
Why Choose Carbon Zero Solutions Ltd
- Certified Hybris specialists; compliant with Part L & PAS retrofit standards
- Clean, quick installs with minimal disruption and ethical waste handling
- Survey-ready documentation and clear, written quotes (no surprises)
- Covering Hampshire, Surrey, Sussex, Kent, Oxfordshire, Berkshire & Wiltshire
Related Reading
Is Your Insulation Actually Working? •
Loft Condensation & Health Risks •
Spray Foam Removal (Survey-Ready)
Click the link above to read more.
