Glass Wool Board Insulation: Rigid Slab for Equipment and Roofs

Glass Wool Board Insulation

Glass wool board is a rigid slab of bonded glass fibers used where the insulation must hold its shape: equipment casings, flat roofs, behind cladding and as a stable base for weatherproofing. DonFoil supplies it plain or faced with FSK, PSK or MSK foil laminate.

Technical specifications

Property	Typical for glass wool	DonFoil grade data
Material	Glass fiber with thermosetting resin binder	By grade
Form	Rigid slab	Slab
Density	About 24 to 120 kg/m3 by grade	On request
Thermal conductivity (lambda)	About 0.030 to 0.040 W/(m*K)	On request
Compressive behavior	Holds shape under light load	By grade
Fire classification	Non-combustible, Euroclass A1 / ASTM E84 Class A (fiber)	By grade
Facing options	FSK, PSK, MSK, or unfaced	All options
Common dimensions	Slab 0.6 x 1.2 m, thickness 25 to 100 mm	On request

Figures marked typical reflect common glass wool values. DonFoil grade-specific density, lambda and dimension data is supplied on request or with the product data sheet.

What glass wool board is

The board is the same glass fiber mat compressed and bonded into a rigid slab. It resists compression far better than blanket but snaps if folded, so it is cut and bedded rather than bent.

Where glass wool board is used

It is specified for equipment casings, flat roofs under the waterproofing membrane, cladding backing and plant rooms where a dimensionally steady slab is needed. As duct board it gives a smooth, stable surface for lining air handlers.

Facing options

FSK facing suits general HVAC and equipment. PSK is chosen where a polypropylene scrim is preferred, and MSK gives a metallized finish. Plain board is supplied when a separate jacket is used. See FSK facing, PP scrim kraft facing and MPET scrim kraft facing for the laminate details.

Installation notes

Score both faces with a sharp knife and snap along the line, or use a fine-tooth saw for clean edges. Bed the board on adhesive or mechanical fixings and seal the board edges so there are no thermal bridges at joints. For roofs, use the board as the thermal layer under a separate membrane.

Common mistakes

Bending the board instead of cutting it cracks the slab. Over-compressing it under a load raises lambda and loses thickness. Leaving gaps at board joints creates thermal bridges, and exposing unfaced board to weather without a jacket lets water reach the fiber.