HardRock® Underlay Slab
Thermal and acoustic insulation for flat roofs.
1/2
Application(s)
- Roof
- Flat Roof
Product description
Designed to be installed with HardRock® Multi-Fix DD, HardRock® Underlay is a vital component in a ROCKWOOL flat roof solution. Manufactured from non-combustible stone wool, this robust product offers a thermal and acoustic foundation for a insulated flat roof system.
*Subject to application
- Euroclass A1 in accordance with BS EN 13501-1 Reaction to Fire rating
- Thermal conductivity 0.039 W/mK
- 70kPa Declared Compressive Strength
- Up to 120 minutes of fire integrity and insulation*
Areas of application
HardRock® Underlay Slab is suitable for use on the following construction types:
- Flat roof – in conjunction with HardRock® multifix DD
Documentation
Hardrock Multi Fix DD Datasheet
HardRock Multi-Fix (DD) is a BBA-approved dual-density insulation board suitable for various surfaces, including flat roofs. In addition to thermal comfort, it provides independently tested acoustic and fire resistance properties.
Hardrock Multi Fix DD BBA Certificate
Certificate No. BBA-21-5878
SUIS ROCKWOOL UK
Safe use instruction sheet ROCKWOOL stone wool insulation products
Republic of Ireland Price List
Price List March 2025
UK Price List
Price List March 2025
Product properties
| Name | Value | Test standard | Symbol | Unit |
|---|---|---|---|---|
| Declared thermal conductivity | 0.039 | EN 826 | λD | W/mK |
| Reaction to Fire | A1 | EN 13501-1 | Euroclass | |
| Long term water absorption | WL(P) | EN 12087 | WL(P) | kg/m² |
| Short term water absorption | WS | EN 1609 | WS | kg/m² |
| Product standard | EN 13162:2012+A1:2015 | |||
| Facing type, side 1 | No Facing |
Product variants
Looking for answers?
Whether you need help finding a local stockist, have a technical question, or want to speak with a sales representative, we’re here to help. Choose the option that best fits your needs.
Speak to an expert
If you have technical questions about products or need support for your project our technical experts are here to help you.
Find sales representative
Find your local ROCKWOOL UK & Ireland sales representative.
Find a stockist
Find a stockist where you can purchase ROCKWOOL stone wool insulation and fire protection products.
