naturheld - It’s nature’s way of building the future

We need to reduce the energy our buildings consume to combat climate change. ANDRITZ and naturheld have therefore pushed the sustainability and technical boundaries in wood-based insulation.

Insulating homes and other buildings is one of the most effective ways of limiting climate change, be it to keep them warm in winter or cool in summer. The fact that typical insulation materials, such as mineral wool or fiberglass, are derived from non-sustainable materials therefore presents a dilemma.

In this context, the alternative of using wood-based insulation has grown in popularity, and the family-owned Ziegler Group, with the biggest sawmill in Europe among its 33 locations, saw an opportunity to develop a sustainable solution for insulating homes using a proportion of the woodchips which are an existing side-stream from its timber processing.

And so a new member of the Ziegler Group, naturheld GmbH, was born in Hütten in Germany. Its two pressurized refining systems and entire chip handling equipment were ordered from ANDRITZ in 2021. Together, they produce three main categories of product, including blown-in insulation for application between walls, ceilings, and floors in timber-frame construction. Then there are insulation boards weighing 110 – 220 g/m², which serve as underlays for roofs and walls. And thirdly Flex, a flexible material weighing 50 g/m², which can be cut to size to fit in the spaces between rafters.

A “tree to building” philosophy took root in the Ziegler group in 2018, when it bought a house-building company near Nürnberg specializing in timber-frame construction, thus giving rise to the launch of Ziegler-Haus. “From this base we considered how house-building could become more efficient and sustainable, and insulation offered interesting possibilities,” says Andreas Sandner, CEO of the Ziegler Group. “We started to look at how it is produced and concluded that the chips from our sawmill were the perfect raw material in terms of suitability for the purpose and for reducing carbon dioxide emissions from construction.”

naturheld GmbH, Hütten (Germany) is part of the Ziegler Group, a family-owned business founded in 1948 with more than 33 locations in Germany.

One tree, one journey

“The fact that the harvested tree makes a single journey to the sawmill, and that the distance for chip transportation from our sawmill to our insulation plant is so short, significantly reduces CO₂ emissions,” continues Andreas Sandner.

“This is the kind of smart and sustainable solution the sector needs and is applicable to all types of construction, from new builds to refurbishment. This is the rationale for establishing naturheld as a business.”

The complete ANDRITZ installation was commissioned in just a few months. Despite much of the work taking place amid the challenges of the COVID pandemic, and the need to coordinate things with the extensive civil engineering work on this greenfield site, the project turnaround time was impressively fast.

The scope of supply in this substantial delivery comprised two fiber processing systems with pressurized refining, each with a production capacity of up to ten tons per hour. Here are the details:

1. Chip handling system from the truck off-loading station with a tilting floor via chip feeding to the chip bin discharger.

2. Chip feeding from the chip bin discharger to the two pressurized refining systems.

3. Plug screw feeder for optimal dewatering before refining, including innovative wear protection for a longer screw lifetime.

4. C-feeder for a consistent supply of wood chips into the high-consistency refiner and stable operation throughout the performance range.

5. 44’’-1CP refiner (single disc) for the production of high-quality fibers with the lowest possible energy consumption.

Innovation at its finest: in naturheld’s board form, wood fiber insulation is 100% compostable and recyclable at the end of its useful life.

naturheld’s production facility is entirely self-sufficient, with spruce and pine wood chips coming from Ziegler’s nearby sawmill operations, energy derived from bark (along with a 2.2 MW solar PV installation when the sun shines), and on-site water treatment. The Group ensures the entire log is used within a fully sustainable process with no production waste and minimal transport.

naturheld Commercial Site Manager Florian Bösl

Andreas Sandner, CEO of Ziegler Group

Robert Friedl, CEO of naturheld GmbH / CTO of Ziegler Group

Full focus on sustainability: the short distance for chip transportation from naturheld’s own sawmill to the insulation plant significantly reduces CO₂ emissions per cubic meter of finished product.

The world’s most modern mill for insulation board production with ANDRITZ chip handling equipment and two pressurized refining lines.

ANDRITZ’ new generation of pressurized refining systems. High dewatering efficiency at the plug screw before refining itself ensures that much less water or condensate enters the refiner, thus requiring less drying energy.

Chip feeding to pressurized refining systems, ANDRITZ Chip Handling System

Pushing technical boundaries

“Thanks to ANDRITZ, we believe we have the most modern factory in the world for the production of wood-fiber insulation products, and they continue to support us in every way necessary,” says naturheld Commercial Site Manager Florian Bösl.

“It’s been a great cooperation, a true partnership that continues to this day,” agrees Robert Friedl, CEO of naturheld GmbH, CTO of Ziegler Group. “One particularly notable feature is the two silos storing spruce and pine chips separately to deliver a consistent and defined mixture to the low-energy refiners. This ensures we always deliver the same high quality through a very efficient manufacturing process. Also, with dedicated lines for hardboard and softboard, we can optimize the production of each. The integration of the production lines around a controlled chip-feeding system from the silos was the main challenge, particularly in view of the short time frame for delivery. But the teamwork between naturheld and ANDRITZ and a ‘can-do’ attitude on both sides have delivered a great result.”

A growing market segment

The market share of wood fiber products in the insulation market stands at around five percent, but ANDRITZ’s state-of-the-art technology and exceptional service are enabling a growing list of companies to follow a similar path to naturheld and enter a growing market segment for sustainable insulation.
“Market feedback on our product is very positive, particularly for a new entrant on the market. The biggest win from this great cooperation with ANDRITZ is that we can create a sustainable product to meet the environmental challenges of the future,” concludes Florian Bösl.