Which Aluminium Spreader Plate Do I Need?

Aluminium heat diffuser plates are designed to hold underfloor heating pipe securely within timber joists while maximising heat transfer into the room. We offer a full range of fit-from-above and fit-from-below spreader plates for 16mm pipe systems:

• Fit From Above Spreader Plates – Designed to span standard 400mm centred joists, these plates are installed from the top side of the floor. Choose:
  • Double Plates – Hold two pipe runs at 200mm centres, ideal for standard applications.
  • Triple Plates – Hold three pipe runs at 150mm centres for higher heat output, perfect where lower flow temperatures are required such as with heat pump systems.
• Fit From Below Spreader Plates – Ideal where it is not possible to remove the floor above. Installed from underneath, these plates are available as:
  • Double Plates – Hold two 16mm pipe runs at 150mm centres.
  • J Plate – A single-run plate used alongside a double plate to achieve three pipe runs per joist cavity, giving maximum heat output for heat pump installations.

For most projects, double plates provide an efficient solution, while triple plate options or double + J plate systems deliver higher outputs and are recommended where underfloor heating is supplied by a heat pump at lower flow temperatures.