Insulation Below A Groundbearing Slab – Sitework

thermal insulation


  1. To provide a smooth surface, blind the hardcore using sand.
  2. Install DPM/Radon barrier.
  3. Determine necessary height for edging and cut Ballytherm boards accordingly. Place vertically around edge of floor.
  4. Position boards across floor in broken bond.
  5. Position boards tightly against each other including at edges and around obstacles.
  6. Lay VCL, lap and then seal every joint.
  7. Pour and tamp slab.
  8. Pour screed.


Prior to pouring slab, test any embedded services. To prevent damage to Ballytherm boards use barrow boards whilst pouring the slab and screed. When levelling the slab, protect exposed edges of the boards. Finally, be certain when fitting boards together to obtain as close a fit as possible.

Find out more:

For more information about Ballytherm thermal insulation for under groundbearing slabs, contact one of our technical experts at 0800 644 6900, or email us at Alternatively, fill out our contact form here and one of our agents will be in touch shortly.

Floor Insulation


Design Guidance