When screwing down insulation and waterproofing, appropriate fixings and pressure distribution plates must be used. The type and size of these fixings depend on the substrate, insulation thickness, and the type of waterproofing (single or multi-layer).
Important: The fixing pattern of the waterproofing membrane is independent of the fixing pattern for the insulation.
Insulation boards must always be fixed according to the prescribed pattern below. The waterproofing membrane is then installed with a number of fixings adapted to the wind load.
For mechanical fixation of the insulation, apply sufficient screws per insulation board according to the appropriate fastening pattern:
| IKO Enertherm Board Size | Minimum Number of Fixings |
|---|---|
| 1200 x 600 | 4 |
| 1200 x 1000 mm | 4 |
| 1200 x 1200 mm | 4 |
| 1200 x 2400 mm | 6 |
| 1200 x 2500 mm | 6 |
Key Considerations:
- Tule fixings help reduce thermal bridging, contributing to a better EPB (Energy Performance) score.
- For profiled steel decks, screws must penetrate the steel by at least 15 mm.
For timber substrates, screws must be driven at least 30 mm into the structural layer. - For Indoor Climate Class IV, the vapour control layer must not be perforated, meaning mechanical fixation is not allowed in such cases.
For more details, consult our guide “Everything About Installing PIR Insulation on a Flat Roof”, available on the IKO website.