Pressure-resistant flat roof insulation with GLAPOR cellular glass for walkable flat roofs

cellular glass is ideal for flat roof insulation: non-combustible, extremely pressure-resistant and permanently moisture-resistant.

Up to 30 % energy savings thanks to flat roof insulation

Flat roof insulation is more than just thermal insulation – it is a central functional element of the entire roof structure. In addition to insulation performance, fire protection, moisture resistance, pressure stability and removability are particularly important today.

This is precisely where GLAPOR cellular glass sets new standards: non-combustible, dimensionally stable, ecological and permanently functional – even under extreme conditions.

cellular glass is ideal for:

Green roofs: pressure-resistant, root-resistant and rot-proof
Accessible roofs: permanently load-bearing under slabs or technology
PV roofs: stable and non-combustible – without material ageing
Sloped insulation: can be cut to size, free of harmful substances

Advantages of cellular glass compared to other flat roof insulations

Criterion	GLAPOR cellular glass boards	EPS / XPS / PUR	Mineral fiber insulation
Raw material	✓ 100 % recycled glass	Petroleum-based	Sand & lime (mined)
Water absorption	✓ None (vapor-tight)	Possible through diffusion	Possible
Compressive strength	✓ Up to 1,600 kPa - also suitable for parking decks	Max. 700 kPa	Rather low
Fire protection class	✓ A1 (non-combustible)	B1-B2 (combustible)	A1
Emissions / leaching	✓ None - emission-free	Waste is dispersed during processing	Fiber dust possible during installation
Waste disposal	✓ Reusable, urban mining ready	Construction waste or hazardous waste	Cumbersome, partly landfillable (for bitumen lamination)
Lifespan	✓ Lifelong - across generations	Characteristics fluctuate when exposed to moisture	Properties change with moisture

Flat roof insulation with cellular glass: processing options

Classic: Flat roof insulation with cellular glass laid in hot bitumen

Underflow-proof high-security system for demanding flat roof constructions and high-rise buildings

Innovative: GLAPOR Urban Mining Smart Roof

The ecological basis for green roofs, retention roofs and roof turf: recyclable, non-combustible and urban mining ready

Not sure which product

is the right one for you?

GLAPOR Technology Team

+49 (0) 9633-400769-0
technik@glapor.de

Guaranteed free of charge & non-binding

The structure of flat roof insulation

Depending on the roof type and use, a professional flat roof structure essentially consists of the following layers:

Supporting structure (e.g. reinforced concrete, trapezoidal sheet metal, timber formwork)
Vapor barrier: This is not required for cellular glass boards bonded in hot bitumen. A vapor barrier is required in the circular Glapor UMS Roof.
Thermal insulation with GLAPOR cellular glass boards – moisture-resistant, dimensionally stable, non-combustible
Sealing: Two-layer bituminous or single-layer plastic-based – depending on the usage category in accordance with DIN 18531. Glapor systems can also be combined with plastic waterproofing systems
Useful or protective layer – e.g. gravel gravel, green roof structure or PV mounting systems

For particularly sustainable roof constructions – such as green roofs or retention roofs – GLAPOR offers the Urban Mining Smart Roof, a bitumen-free, loose-laid flat roof system that is completely mineral, pollutant-free and reversible. The system is compatible with modern leak detection technologies and meets the highest ecological and cradle-to-cradle requirements.

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✔ Customized project consulting

cellular glass 100% made in Germany

✔ 1 00+ million m³ of cellular glass installed

✔ Customized project consulting

cellular glass 100% made in Germany

✔ 100,000,000+ m³ of cellular glass installed

Frequently asked questions (FAQ) about flat roof insulation

FAQ

What thickness should flat roof insulation have?

The required thickness depends on the desired U-value and the insulation material used. According to the German Building Energy Act (GEG), the U-value should not exceed 0.20 W/(m²K). With cellular glass, this value can already be achieved with a lower insulation thickness.

What is the best flat roof insulation?

The optimum insulation combines good insulation values, fire protection, compressive strength and environmental compatibility. cellular glass meets all these criteria and is therefore an excellent choice for sustainable construction.

How high should the compressive strength of flat roof insulation be?

The required compressive strength depends on the planned use of the flat roof. For accessible roofs, roof terraces or green roofs, insulation materials with compressive strengths from 600 kPa (PG 600) are generally sufficient. For higher load requirements – e.g. for technical areas, intensive greenery or parking decks with occasional to regular vehicle traffic – higher compressive strengths are necessary.

GLAPOR cellular glass sheets are available in various compressive strength classes – up to 1,600 kPa – and are therefore also suitable for heavy-duty flat roof constructions, for example in traffic areas, parking decks or helipads. Thanks to their mineral structure, they retain their shape permanently, even under long-term loads and changing climatic conditions.

Is flat roof insulation flammable?

This depends on the material used. While EPS, XPS and PUR are combustible, cellular glass is non-combustible (A1) and therefore offers a high level of fire protection.

How much does flat roof insulation cost?

The costs vary depending on the material, roof size and structure. On average, the costs are between 50 and 150 euros per square meter. cellular glass is more cost-effective in the long term compared to petroleum-based insulation materials such as XPS or PUR due to its durability and maintenance-free nature.