Underfloor Insulation Installation Instructions



Koolfoam Underfloor Insulation panels are cut from S class Polystyrene
The sheets are 1.2m long with concertina cuts down both edges
The sheets are cut to various widths and are all 60mm thick

The concertina edges allow the installer to obtain an easy snug friction fit between the floor joists and it is required that the Koolfoam Underfloor Insulation panels are pushed up hard to the underside of the floor to
retain the maximum construction R value.


Tape measure
Stanley knife with extendable blade
Straight edge


Step 1

Measure gap between floor joists.

Step 2

Choose a panel of Koolfoam Underfloor Insulation with the correct size. If cutting is required cut the panels at least 2mm greater than the distance between the framing members.

Step 3

Push one edge of the panel up against the corner between the floor joist and the floor and then push up on the other side squeezing the concertina edge. until it is fitted between the floor joists and then push the panel hard up to the underside of the floor. This will ensure a good friction fit of the Koolfoam Underfloor Insulation panel.

Step 4

Repeat Step 3 for the next panel ensuring that each panel is butted together end to end with no gaps and is tightly fitted between the framing members.

Step 5

Ensure the entire floor area is insulated. Check and repair any visible gaps
by using insulation off cuts or foam to fill small gaps around plumbing or other protrusions and where joists lap.


If the sheets are slightly loose use the Koolfoam PVC Fixing Clips to hold the sheets in place by simply placing the clip hard up underneath the Koolfoam Underfloor Insulating panel ensuring the insulating panel is hard to the underside of the floor and staple the bracket or nail it to the floor joist. Ensure that the nail is galvanised or that the staple is stainless steel.


Electrical cables should not contact Koolfoam Underfloor Insulation panels.

Methods to avoid contact

1 Sleeve cables in conduit.
2 Use polyethylene or polypropylene tape between the PVC and polystyrene.
3 Use cables with a non migratory PVC sheath.
4 Separate electrical cables from Insulation panels with a strip of paper.


EPS insulating panels must be separated from all sources of heat and naked flames.

BLACK PEARL Underfloor Panel Sizes

360*1.2*60mm R1.5
410*1.2*60mm R1.5
470*1.2*60mm R1.5
560*1.2*60mm R1.5


Installation instructions for Koolfoam underfloor insulation in MS Word format