Klimaver solid wall – Advancement of precast construction through expanded glass granulate

Since 1904, H+L Baustoffwerke have been a family-run medium-sized enterprise with locations in the German towns of Glauchau and Uehlfeld. The company is specialized in planning, production and logistics of precast concrete elements and, as a system provider, they offer all necessary steps from quotation processing to project planning and production through to delivery and assembly from a single source. The objective is a consistently coordinated construction process with clearly structured workflows. The company‘s development comprises numerous technical extensions, including the introduction of various wall and floor systems since the 1970s and the start-up of additional production sites. The company can look back on more than 120 years of continuous activities in the field of precast concrete production.

As specialist in solutions for shell construction, H+L combines profound material knowledge, modern production technology and a consistently sustainable requirement on the construction of the future. The development of the Klimaver solid wall sets an innovative milestone in terms of ecologically optimized precast elements. This makes the manufacturer the only supplier of prefabricated exterior walls made of expanded glass granulate (according to one‘s own information )– a building material that combines ecological responsibility with excellent building physics properties.

Expanded glass granulate as key material of the Klimaver solid wall

The Klimaver solid wall is based on a high-performance expanded glass granulate made by Liaver, a company of the Sto Group. It has been manufactured from pure waste glass in a monitored process since 1996. Recycled crushed glass is finely ground, mixed and shaped. The raw granulate is sintered in a special kiln at up to 900 °C. Due to its advantageous combination of low grain bulk density, high grain strength and dense surface, the mineral material has proven itself in many ways in the field of construction. It is resistant to moisture and absolutely free of contaminations. The mineral material is distinguished by a low grain bulk density, high grain strength, closed surface and thus an extraordinarily good moisture resistance. Free of pollutants and permanently dimensionally stable, the granulate meets highest ecological and structural requirements. To get the Klimaver mixture, the loose Liaver expanded glass granulate is processed with a specially designed cement without any additional aggregates. Afterwards, this mixture is placed in the form that has been prepared accurate to dimension. Following the controlled drying process in weather-independent production halls, the finished wall panels are prepared for transport to the construction site and delivered for installation.

Lightweight concrete structure and conservation of resources thanks to expanded glass

The grain size of 2 - 8mm applied in the precast element gives the lightweight concrete a porous structure, offering numerous advantages: The entrained air provides for excellent insulation properties, whereas the mineral grain strength ensures the required high compressive strength. The decisive factor is the optimized pore structure that has been further developed over several years and makes the material to the one and only expanded glass granulate today that is suitable for prefabricated element construction with solid walls using expanded glass granulate.

Moreover, the building material makes an important contribution to the conservation of resources: It reduces the input of natural raw materials, such as sand and gravel, and allows for its high-grade upcycling as insulation material after a service life of at least 50 - 100 years.

Ecology, efficiency and healthy housing

With the market launch of Klimaver, H+L pursues a clear approach: to realize high-quality building envelopes without any additional thermal insulation composite system – and this on the basis of a low-emission, durable building material ensuring healthy housing. The solid wall is open to vapor diffusion, absorbs hardly any water, while complying with the requirements of the highest fire protection class A1  (REI90) simultaneously.

Hence, the Klimaver solid wall provides an above-average performance profile not only in structural terms, but above all in respect of healthy housing and sustainability. Especially under present demands on energy and comfort, it is essential to choose low-emission building materials because more and more airtight building envelopes require materials that control moisture, prevent the formation of mold and support a permanently balanced living climate.

The development of the Klimaver solid wall

With product development in 2021 and the market launch of the Klimaver solid wall in 2022, H+L Bau-stoffwerke pursued a clearly defined vision. The goal was to develop a sustainable wall building material that meets the increasing technical, ecological, and structural requirements for modern building envelopes.
The development goals focused on the following aspects:

the consistent avoidance of composite thermal insulation systems for exterior walls,

the development of an ecological and resource-saving wall construction material,

the achievement of optimal building physics values, and

the recyclability of the material in line with the circular economy principle.

Against the backdrop of increasingly higher requirements for building envelopes—especially for the thermal insulation of exterior walls—H+L Baustoffwerke needed to develop new lightweight concrete additives. These were intended to enable a significant improvement in thermal insulation properties without negatively affecting the structural and building physics properties.
The product development was preceded by comprehensive simulations of the long-term shrinkage behavior of the walls in collaboration with the IAB Weimar. In addition, corresponding evidence was provided in the areas of building physics, statics, and fire protection. The results of these investigations confirm the high performance of the system: The walls are diffusion-open, have very low residual moisture, do not absorb any more water, and are classified in the highest fire protection class A1.

The market success of the Klimaver solid wall is reflected in continuously increasing sales volumes. Since its market launch in 2022, more than 20,000 m² have already been produced. The range of applications extends from single-family homes to semi-detached and terraced houses to large-scale projects such as senior citizens’ resorts and multi-storey residential buildings, which have since been realized by H+L Baustoffwerke.

EPD certification 2023

In 2023, the Klimaver solid wall was granted an Environmental Product Declaration (EPD) of the German Building and Environment Institute (IBU - Institut Bauen und Umwelt e.V.). This internationally recognized certification documents the overall ecological life cycle assessment across the entire life cycle – from raw materials up to dismantling. The certificate confirms the climate-friendly character of the product and provides planners, clients/contractors and architects with a sound basis for sustainable building evaluations.

Comprehensive benefits in planning, construction and usage

The Klimaver solid wall combines robust solid construction, long service life, natural insulation and healthy housing in a single product. Architects and planners benefit from a tried and tested, industrially optimized wall system which meets all requirements of modern sustainability standards, simultaneously.

There are obvious advantages for building contractors and inhabitants:

low-emission construction method that is open to vapor diffusion

comfortable indoor climate that is permanently controlled

high energy efficiency without any additional exterior insulation

solid, durable building shells with stable in value

effective protection against fire, heat and sound.

This positions Klimaver as a future-oriented alternative to conventional wall structures – in particular, for environmentally- and health-conscious construction concepts.