Foam Glass: Innovative Insulation Material for Building Projects

Are you planning a renovation or new build? Choosing the right insulation material affects energy efficiency, living comfort and sustainability. Foam glass is a versatile and robust alternative. This article explains what foam glass is, where you can use it and what benefits it offers.

What exactly is foam glass?

Foam glass is a mineral insulation material. Its raw material is recycled waste glass, usually from bottles or window panes. The glass is crushed, cleaned and put through a special foaming process.

In a rotary kiln at temperatures of around 900 degrees Celsius, the glass granules expand. This creates a closed-cell, porous granulate with a stable foam structure. The granulate is sold as loose fill or processed into rigid boards or moulded components.

Its production closes the material loop for glass. The result is a durable building material with outstanding properties.

“Foam glass creates the perfect combination of sustainability and performance. Waste becomes a high-quality, non-ageing insulation material that protects buildings for generations.”

What are the benefits of foam glass insulation?

Its material properties make foam glass interesting for many applications. It is versatile and long-lasting.

High compressive strength and dimensional stability

Foam glass boards can withstand high loads. They do not settle. This makes them ideal for insulating beneath ground slabs, terraces or flat roofs. Even beneath trafficked courtyard surfaces, their insulating performance remains fully intact.

Completely resistant to moisture

The material is water-repellent and capillary-breaking. It does not absorb water. As a result, it does not lose its insulating performance in wet soil or during driving rain. You can install it directly in the ground.

Non-combustible and resistant to pests

Foam glass is mineral-based and therefore non-combustible (building material class A1). It does not provide a breeding ground for mould, algae or vermin. Mice and rats cannot gnaw through it. This ensures hygienic and safe conditions.

Where can I use foam glass in and around my home?

Applications range from the foundations to the roof. The two main forms—loose fill and boards—determine where it is used.

Building envelope insulation: perimeter and ground slab

Boards are used here. They insulate the below-ground exterior walls of the basement (perimeter insulation) and are installed beneath the ground slab. This prevents thermal bridges and protects against rising damp. For all work involving plumbing and insulation, you will find suitable accessories in our range.

Roof insulation and flat-roof construction

Foam glass is ideal as a load-distributing layer beneath green roofs or gravel. It provides insulation and drainage and is root-resistant. On pitched roofs, the granulate is suitable as loose fill in cavities or between rafters.

Loose fill for cavities and beneath screed

Pour the granulate into cavity ceilings or into the floor build-up beneath the screed. It provides excellent insulation against impact sound and heat loss. It is easy to install and produces little dust.

“Foam glass is particularly effective in existing buildings. It can be blown into existing cavities, is compatible with older building materials and provides retrofit insulation that lasts without major intervention.”

How sustainable is foam glass really?

The environmental profile of foam glass is convincing on several levels. It helps address the problem of construction waste and waste glass.

Its high recycled content conserves natural resources such as sand and crude oil. The building material itself is 100% recyclable. After dismantling, you can melt it down again and process it into new insulation granulate.

Its service life of over 50 years without loss of performance saves resources for replacement work in the long term. Its resistance to moisture prevents building damage and subsequent renovation.

Foam glass in gardening and landscaping

You can also benefit from its advantages outside the home. In the garden, foam glass performs several functions at once.

As a drainage layer beneath terrace paving, it reliably channels water away and prevents frost damage. In raised beds, it serves as a mineral, rot-proof drainage layer. For gardening, our range has all the tools you need.

You can use it as a lightweight filler for gabions or as a substrate for extensive green roofs. Its neutral properties do not harm plants.

How much does foam glass cost compared with other insulation?

Foam glass is in the mid-to-upper price range for insulation materials. Its material costs are higher than those of conventional EPS (polystyrene).

However, you are investing in an extremely durable, maintenance-free solution. Savings from lower heating costs and avoided repair costs can make the investment pay off over the years. Calculate the total cost over the building’s service life.

Conclusion: Who is foam glass suitable for?

Foam glass is the right choice for builders who value durability and sustainability. It is particularly suitable for building components in contact with the ground, areas at risk of moisture and locations exposed to high mechanical loads.

If you are looking for a durable, damage-resistant and environmentally friendly building material, foam glass is an excellent option. It reliably protects your home from cold and moisture while helping to maintain a healthy indoor climate.

For practical implementation on the building site, our range in building tools contains everything you need. Our products support you from planning through to execution.

Suitable products for your insulation project

Flexible pipe insulation is ideal for insulating installations such as heating or water pipes. It minimises heat loss and prevents condensation.

AEROFLEX® SH XT pipe insulation - 2 m, self-adhesive, flexible insulation material made from closed-cell foam rubber, black - 54 x 10 mm

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AEROFLEX® SH XT pipe insulation - 2 m, self-adhesive, flexible insulation material made from closed-cell foam rubber, black - 28 x 10 mm

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For all other materials for professional pipe insulation, visit our pipe insulation category.

Frequently asked questions

Is foam glass sustainable?

Yes, foam glass is considered highly sustainable. It consists of more than 80% recycled waste glass, often sourced from the Green Dot recycling system. The manufacturing process requires energy, but its durability, reusability and contribution to a closed-loop material cycle make it an environmentally friendly building material.

Where can I use foam glass in home construction?

Expanded clay granules are often used as loose-fill insulation in cavities in floor slabs, beneath screeds or in roof structures. In board form, foam glass is suitable for perimeter insulation around foundations. It can also be used as insulation in timber-frame walls or for green roofs.

How does foam glass perform as thermal insulation?

The thermal conductivity (lambda value) of foam glass is between 0.065 and 0.085 W/(mK). This gives it good insulation properties, comparable to other mineral insulation materials. However, for very high efficiency standards such as passive houses, you will often need thicker layers than with high-performance insulation materials.

Can I install foam glass myself?

You can install loose-fill foam glass granules yourself for small projects. Make sure they are distributed evenly and that you use the recommended fill depth. Because correct installation and sealing are essential, foam glass boards for perimeter insulation should be installed by a professional.

Is foam glass also suitable for the garden?

Yes, foam glass granules are excellent for use in the garden. You can use them as a drainage layer beneath patio slabs or paths. They prevent waterlogging, help suppress weeds and are frost-resistant. They are also used as a mineral substrate in raised beds or for green roofs.