Renovations & Retrofits

Renovations and retrofits present different challenges to new builds.

Existing floor structures, limited build-up heights, mixed substrates and staged construction require underfloor heating systems that are thin, predictable and adaptable — without compromising comfort or flooring protection.

This document explains how underfloor heating can be successfully integrated into renovation and retrofit projects, and what design principles must be applied to ensure performance, safety and long-term stability in existing Australian and New Zealand homes.

Renovations often involve:

• limited floor build-up height

• existing slabs or timber subfloors

• mixed floor finishes

• staged installation timelines

• occupied dwellings

Heating systems must adapt to the building — not the other way around.

Modern thin-profile underfloor heating systems allow:

• minimal impact on finished floor levels

• integration over existing slabs and old floors

• compatibility with timber subfloors

• reduced demolition and disruption

Thin systems reduce thermal inertia and improve responsiveness.

Renovation projects frequently combine:

• tiles in wet areas

• timber or hybrid floors in living zones

• existing and new finishes

Design must account for:

• different thermal conductivities
• different floor build-ups from different type of floor coverings

• surface temperature limits

• zoning separation

• control calibration

Staged renovations benefit from:

• independent heating zones

• modular electrical design

• flexible control architecture

• future expansion capability

Zoning allows heating to be installed progressively without performance compromise.

Existing substrates may contain:

• residual moisture

• uneven surfaces

• unknown adhesive history

Specification must prioritise:

• surface temperature stability

• conservative wattage density

• controlled commissioning

• verification of moisture conditions

Retrofit commissioning must consider:

• gradual warm-up cycles

• occupant comfort

• protection of existing finishes

• staged system activation

• Renovations require adaptable heating systems

• Thin-profile solutions minimise disruption

• Mixed floor finishes require zoning and control

• Conservative design protects existing structures

• Staged installation improves flexibility

• Controlled commissioning protects finishes

DS-01 — How to Specify Underfloor Heating in Modern Buildings

DS-02 — Floor Build-Ups, Adhesives & Surface Temperature Limits

DS-05 — Commissioning, Warm-Up Cycles & Long-Term Stability