Pressure-resistant sloped insulation for flat roofs, terraces & balconies

Sloped insulation ensures controlled water drainage and protects flat roofs, terraces and balconies from moisture damage – efficiently and ecologically with cellular glass.

Non-combustible sloped insulation for flat roofs

Sloped insulation is a special form of thermal insulation that integrates a slope for targeted water drainage. It is mainly used on flat roofs, terraces and balconies to prevent standing water and the associated damage. The standard gradient is min. 2%.

Typical areas of application:

Flat roofs (warm, cold or inverted roof)
Balconies and loggias
Roof terraces and accessible roofs
Parking decks and garage roofs

The use of sloped insulation means that there is no need for costly screed work.

Glapor offers different slope systems: 1.0 – 1.7 – 2.0 – 2.5 – 3.3 – 5.0%. cellular glass roof riders are also available on request

Sloped insulation in comparison

Criterion	GLAPOR sloped insulation boards made of cellular glass	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
Disposal	✓ Reusable, urban mining ready, disposal class Z0 "harmless"	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
Cutting and fabrication	✓ Available in many slope systems, also: roof rider ("pig's back")	available as a slope, often expensive or not available as a roof rider	Available as a slope

Sloped insulation with cellular glass: processing options

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

Absolutely backflow-proof and resilient sloped insulation with sloped insulation boards laid in hot bitumen.

Innovative: GLAPOR Urban Mining Smart Roof

Circular, highly pressure-resistant gradient insulation made of 100 % cellular glass. Quick and easy installation without adhesives, easily removable.

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

Sloped insulation for flat roofs: what to look out for

The following points must be observed for effective sloped insulation on flat roofs:

Minimum gradient: According to the flat roof guideline, a slope of at least 2 % should be maintained in order to drain water reliably (exception: retention roofs).
Planning: A detailed gradient plan is essential. GLAPOR offers a sloping roof service: preparation of individual planning documents and construction site service
Installation: The sloped roof systems are fully bonded with hot bitumen. In most cases, the UMS Roof flat roof is installed without a slope under retention roofs.
Waterproofing: GLAPOR flat roof systems can be combined with all standard waterproofing membranes, including plastic and EPDM waterproofing.

All necessary installation instructions and data sheets are available in the Glapor Technology Library.

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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 slope insulation

FAQ

What thickness should flat roof insulation have?

The required insulation thickness is determined by the desired heat transfer coefficient (U-value) and the thermal characteristics of the material used. According to the German Building Energy Act (GEG), a U-value of ≤ 0.20 W/(m²K) must not be exceeded for the roof as a rule. Due to the low thermal conductivity of cellular glass, the required U-values can often be achieved with comparatively low layer thicknesses. The exact dimensioning is carried out via the component-specific U-value verification.

What is the best flat roof insulation?

High-performance flat roof insulation combines low thermal conductivity, high compressive strength, non-combustible properties and long-term moisture and dimensional stability.

GLAPOR cellular glass fulfills these requirements in every respect: The closed cell structure is permanently waterproof and diffusion-tight, does not absorb moisture and retains its insulating and compressive properties over its entire service life.

The combination of fire protection (A1), moisture resistance, load transfer and environmental compatibility makes GLAPOR a particularly robust and sustainable solution for flat roofs – in both new builds and renovations.

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

Roof surfaces that can be driven on or walked on – such as parking roofs or roof terraces – require permanently high compressive and surface load resistance. GLAPOR cellular glass offers compressive strengths of up to 1,600 kPa and remains dimensionally stable, compression-free and moisture-resistant even under car and truck traffic loads. Thanks to its closed cell structure, GLAPOR does not absorb moisture, is non-combustible and retains its load-bearing capacity over its entire service life. Also ideal for hospitals, schools and data centers.

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.