Insulating Below Suspended Timber Floors – Sitework

Insulating below suspended timber floors

Installation sequence

  1. Install joists at specified centres.
  2. Fix timber battens to the sides of the joists. *
  3. Cut Ballytherm boards to fit between the joists and set them on the battens.
  4. Lay and fix flooring.

* The distance from the top of the battens to the top of the joists will depend upon the thickness of Ballytherm board specified and whether a service void is specified.
Points to watch

  • Cut Ballytherm boards carefully to give a snug fit.
  • Pack insulation between the perimeter joists and the wall to avoid thermal bridging.
  • Seal service penetrations with flexible sealant.

Further Advice & Information

For more information about Ballytherm products, technical advice, or guidance on the suitability of our products for your project, contact us at + 353 (0)49 95 27000,, email us at or use our contact form.

Floor Insulation


Design Guidance