Isover Spacesaver

Spacesaver is a glass mineral wool roll which is pre-perforated to fit between common joist spacing at ceiling level. It is supplied in longer-length rolls to help increase the speed of installation and ensure more efficient delivery and storage. Other products within the range include Spacesaver Lite, Spacesaver Ready-Cut and Spacesaver Plus. 

Spacesaver can also be considered for use between the joists in suspended timber ground floors and flat roofs.

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Product Features

  • Pre-perforated to 3 x 386mm and 2 x 580mm widths
  • Manufactured from up to 82% recycled glass
  • Achieves Eurofins Gold certification, the highest accreditation for indoor air quality

Fire Classification

Euroclass A1 Reaction to Fire classification according to EN 13501-1.

Product Specification

Thickness (mm) Length (m) Width* (m) λD Declared thermal conductivity (W/m.K) RD Declared thermal resistance (m².K/W)
100 12.18 1.16 0.044 2.25
150 8.05 1.16 0.044 3.40
170 7.03 1.16 0.044 3.85
200 5.20 1.16 0.044 4.50

*Pre-perforated to 3 x 386mm and 2 x 580mm widths

Product Benefits

  • Thermal Performance - Thermal conductivity of 0.044 W/m.K. Helps to reduce heat loss within the building envelope and decrease energy costs.
  • Easy to Install - Supplied in longer-roll lengths for quick and easy installation, maximising on-site efficiency. The rolls are pre-perforated (3 x 386 and 2 x 580mm widths) to fit common joist spacing, or can be used full width for quick coverage.
  • Fire Classification - Achieves a Euroclass A1 Reaction to Fire classification, according to EN 13501-1.
  • Sustainability - Manufactured from up to 82% recycled glass on a plant that uses 100% renewable electricity. For further details visit

Key Considerations

When using Isover Spacesaver, you need to satisfy yourself that use of the product meets all relevant national Building Regulations and guidance as well as local, national and other applicable standards relevant for your construction or application, including requirements in relation to fire and applicable height restrictions.

Please refer to the following product documents: