Perimeter insulation: Effective protection for basement walls and components in contact with the ground

Q: How do I attach a dimpled sheet to perimeter insulation?

A dimpled membrane mechanically protects the perimeter insulation and the underlying waterproofing from damage caused by the adjacent soil. It is not attached directly to the insulation, but positioned loosely in front of it. The necessary contact pressure is only created when the excavation pit is backfilled. Important notes on installation:Orientation of the studs:The studs face away from the building structure, i.e. towards the ground. This ensures an effective drainage function and optimum protection of the insulation. Height of the dimpled membrane:The dimpled membrane should extend approx. 10 cm above the top edge of the waterproofing to ensure complete protection.Overlap:If several sheets are used, an overlap of at least 10 cm is required to ensure a continuous protective layer.End profile:The top edge is fitted with an end profile that fixes the dimpled sheet and protects it from dirt and water.Drainage:Drainage should also be installed at the base so that any water can be reliably drained away.When GLAPOR cellular glass sheets are used, the high compressive strength and water resistance optimally complement the protective effect of the dimpled membrane. The system remains permanently functional – even under extreme mechanical and moisture loads. However, it is not possible to apply simple nopmembranes are installed. Drainage membranes are usually used here, which, depending on the type of waterproofing, are additionally equipped with an integrated sliding, protective and load-bearing layer. verare equipped with a separating layer. The basic distinction between orbital sealingwaterproofingwaterproofing in accordance with DIN 18533-2 and liquid-applied waterproofing in accordance with DIN 18533-3.

cellular glass is ideal for perimeter insulation: pressure-resistant, water-resistant and ecological.

What is perimeter insulation?

Perimeter insulation refers to the thermal insulation of building components in contact with the ground, such as basement walls and floor slabs, on the outside. The aim is to minimize heat loss and prevent moisture damage. This insulation is particularly important as it protects the building from the thermal and moisture-related influences of the ground.

Direct contact with the ground in particular places high demands on the material properties: Pressure resistance, watertightness, rot resistance and dimensional stability over decades are crucial. In addition to conventional insulation materials such as XPS, EPS and PUR, cellular glass is establishing itself as a much more reliable solution.

Advantages of cellular glass as perimeter insulation

GLAPOR cellular glass boards are made of 100% recycled glass, are resistant to ants and rodents and offer a compression-free and mechanically highly resilient insulation solution for demanding perimeter applications.

They combine ecological responsibility with technical durability – even for high-security basements for libraries, data centers or archives. GLAPOR perimeter insulation is approved by the DIBT for use in pressurized water up to 12 m immersion depth. This is unique and is not achieved by plastic insulation materials.

Perimeter insulation with cellular glass:

Basement exterior wall and base insulation

Reliable, secure, high-performance. Lifelong moisture, heat and fire protection. Sustainable insulation with cellular glass boards from Germany.

RDS: Combined perimeter system

The best of two cellular glass worlds: cellular glass boards as edge insulation formwork. Cellular glass gravel as load-bearing thermal insulation. In combination, the healthy basis for every house.

UMB1: Urban mining base plate

The world’s first 100% circular floor slab without concrete made of GLAPOR cellular glass. Quick to install. Insulates reliably, supports up to 68 t/m² and saves up to 95 % CO₂.

How does GLAPPOR RDS combined perimeter insulation work?

The long-term functionality of perimeter insulation requires that the material used can fully withstand the specific stresses of the soil. The following properties are essential:

High compressive strength: For safe absorption of traffic and building loads without deformation.
Water and moisture resistance: Reliable protection against moisture build-up.
Material stability: Resistant to rotting and chemical degradation.

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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

Advantages of cellular glass compared to other perimeter insulations

Criterion	GLAPOR cellular glass boards	XPS
Raw material	✓ 100 % recycled glass	Petroleum based
Water absorption	✓ None (vapor-tight)	Possible through diffusion
Compressive strength	✓ Up to 1,600 kPa - also suitable for parking decks	Max. 700 kPa
Fire protection class	✓ A1 (non-combustible)	B1-B2 (flammable)
Emissions / leaching	✓ None - emission-free	Waste disperses during processing
Waste disposal	✓ Reusable, urban mining ready	Construction waste or hazardous waste
Lifespan	✓ Lifelong - across generations	Characteristics fluctuate with moistening

Frequently asked questions (FAQ) about perimeter insulation

FAQ

What is perimeter insulation?

Perimeter insulation describes the thermal insulation of all components of a building that are in direct contact with the ground – typically external basement walls, floor slabs or foundations.
It not only protects the building from heat loss to the outside, but also permanently protects the building fabric from penetrating moisture.

Which materials are suitable for perimeter insulation?

In practice, two different materials are used to insulate building components in contact with the ground – XPS (extruded polystyrene) and cellular glass in sheet or gravel form. Conventional plastics such as XPS are petroleum-based. cellular glass, on the other hand, consists of 100% recycled glass, is completely recyclable and contains no harmful substances. It is inert, diffusion-proof and therefore absolutely waterproof, permanently dimensionally stable and has no negative impact on soil or groundwater – a sustainable solution for demanding perimeter applications in the spirit of circular, responsible construction.

How are GLAPOR cellular glass boards fixed in the perimeter insulation?

GLAPOR cellular glass boards are bonded with bitumen-free, mineral-based system adhesives over the entire surface and full joints. On absorbent substrates, priming with GLAPOR system primer is required beforehand to ensure even adhesion. After bonding, the boards are given a thin top coat.

Can I also use other adhesives for the installation?

No – the approval of the suitability of an adhesive for bonding Glapor cellular glass boards is approved by Glapor Technik. Note: Bituminous adhesives in particular must not be used with the Glapor RDS system or in areas exposed to sunlight.

How thick must the perimeter insulation be?

The required insulation thickness depends on the energy requirements in accordance with the Building Energy Act (GEG), the calculations of the building physics planning and the use of the building. Insulation thicknesses between 80 mm and 140 mm are usually used. GLAPOR cellular glass boards can also be processed in two layers for increased requirements or for two-layer designs – for example in the area of external basement walls. Bonding is carried out over the entire surface and full joint with the bitumen-free, mineral-based GLAPOR system adhesive. This design not only guarantees a permanent insulating effect, but also extremely high compressive strength up to 1,600 kPa – ideal for demanding load cases in areas in contact with the ground.

How do I attach a dimpled sheet to perimeter insulation?

A dimpled membrane mechanically protects the perimeter insulation and the underlying waterproofing from damage caused by the adjacent soil. It is not attached directly to the insulation, but positioned loosely in front of it. The necessary contact pressure is only created when the excavation pit is backfilled.

Important notes on installation:

Orientation of the studs:
The studs face away from the building structure, i.e. towards the ground. This ensures an effective drainage function and optimum protection of the insulation.
Height of the dimpled membrane:
The dimpled membrane should extend approx. 10 cm above the top edge of the waterproofing to ensure complete protection.
Overlap:
If several sheets are used, an overlap of at least 10 cm is required to ensure a continuous protective layer.
End profile:
The top edge is fitted with an end profile that fixes the dimpled sheet and protects it from dirt and water.
Drainage:
Drainage should also be installed at the base so that any water can be reliably drained away.

When GLAPOR cellular glass sheets are used, the high compressive strength and water resistance optimally complement the protective effect of the dimpled membrane. The system remains permanently functional – even under extreme mechanical and moisture loads.

However, it is not possible to apply simple nopmembranes are installed. Drainage membranes are usually used here, which, depending on the type of waterproofing, are additionally equipped with an integrated sliding, protective and load-bearing layer. verare equipped with a separating layer. The basic distinction between orbital sealingwaterproofingwaterproofing in accordance with DIN 18533-2 and liquid-applied waterproofing in accordance with DIN 18533-3.

How much does 1 m² of perimeter insulation cost?

The costs vary depending on the material thickness and quality requirements. While conventional solutions such as XPS appear cheaper, GLAPOR cellular glass scores points for its longer durability, complete recyclability and minimal follow-up costs. In the long term, cellular glass is the more economical choice.

How high is the perimeter insulation in the base area?

In the base area, the perimeter insulation should extend at least 30 cm above ground level in order to safely cover water spray. GLAPOR cellular glass not only provides insulation here, but also optimum protection against moisture and frost.

What goes under the perimeter insulation?

The professional installation of perimeter insulation requires a stable and even subgrade. A clean layer of lean concrete is usually created for GLAPOR cellular glass slabs. This serves as the basis for the load-bearing thermal insulation and ensures even support and optimum force transmission into the substrate.

The cellular glass boards are bonded over the entire surface and fully joined. Thanks to this processing method and the high material resistance, the system has been approved by the German Institute for Building Technology (DIBt) for use in pressurized water up to an immersion depth of 12 m – a unique selling point in the world of insulation materials.

When using GLAPOR cellular glass gravel (e.g. in the RDS system), on the other hand, conventional planning with an optional additional drainage gravel layer is sufficient. The cellular glass gravel is installed freely, compacted at a ratio of 1.3:1 and leveled – without bonding, completely mineral and removable.

Important: In the GLAPOR RDS combined perimeter system, installation must always be carried out at least 30 cm above the highest groundwater level and a compaction log must be kept (available from us). Load plate compression tests are not suitable for cellular glass gravel.

How is the frost resistance of the GLAPOR Urban Mining floor slab ensured?

Frost protection is ensured by the targeted installation of GLAPOR FSP frost protection boards in the base area of the building. These form a standard-compliant frost shield that functionally replaces the classic, deep-founded frost apron structure.

This not only saves concrete, excavation and construction time, but also enables a material-efficient, demountable foundation – in line with circular construction. This means that the foundation remains frost-free in accordance with DIN EN ISO 13793 – even without conventional reinforced concrete measures, e.g. as a frost apron.