Massiv-Holz-Mauer // Solid Timber Wall

A wall for the future

Article by Günther Jauk, translated by Susanne Höfler | 10.12.2018 - 20:19

If on a cold winter's day, the heating system of the office in the MHM model house in Woringen/DE is malfunctioning Karl-Heinz Karrer will only notice that a day later. The timber engineer likes to use this anecdote to illustrate the excellent thermal storage properties of the MHM system to interested visitors. Karrer already participated in an MHM production line in Saxony in 2005 – during the past year, he decided to launch his own line in the Allgäu region. "We've known for a long time already that the system works. Now, we want to become a local supplier to the growing market in the Allgäu region", Karrer, who put an MHM production in operation at the headquarters in Woringen in April, explains. Next to MHM projects, the carpentry offers its customers conventional timber construction services like roof structures, carports or hall constructions.

Karrer wants to utilize the capacities of his MHM line in two ways: "With my more than 20 employees I can realize around 20 houses per year. In the future, we want to use the remaining MHM volumes to service carpentries from the region."

But not only the MHM system can be found in Woringen – the town has been home to the MHM model house mentioned above much longer. According to Karrer, it is currently the only one of its kind. Next to different wall thicknesses and sample items for visitors to touch, what they especially appreciate is the "great indoor climate that can be felt from the moment you enter". "Combined with the production line, customers can now experience the entire process first hand – from the rough-sawn board up to the completed house", Karrer describes the experience that turned many a skeptic into customers.

Fruitful partnership

Entirely different was the starting starting point for the newly found company R3 Massivholzbau that launched an MHM line in June in the Upper Bavarian village of Asch (near Landsberg am Lech). The co-founders are two architects, one structural engineer, two timber construction companies as well as a biomass farm with the appropriate capacities. In contrast to a conventional carpentry, R3 Massivholzbau considers itself more of a joining center with extensive service features. The aim is to find more firms for partnerships next to the wood farms already participating. The production with more than 100 houses per year is supposed to go into operation as quickly as possible, as timber construction consultant Thomas Rümetz explains – a goal he deems by all means realistic: "Timber construction is becoming increasingly important. With our solid outer walls of more than 20 cm, we offer an exceptionally great alternative to conventional solid construction." Since the launch of production, several single-family homes as well as a large-scale office and commercial building have  already been realized.

Regional value creation

The story of Sterk Holzhaus (Sterk timber house) is remarkable – even though strictly speaking, it hasn't even started yet. Only in 2019, the young company will start supplying its customers with first MHM elements. Founded in 2001 as an individual enterprise, Klaus Sterk today calls the divisions Sterk Building Design, Sterk Screed and since 2014 also the Sterk Joining Center his own which he is running together with Franz Zodel. The latter has already been working with CNC controlled joining as well as CAD planning of timber construction projects for the past 20 years.

"Just like with the joining center, we also won't bring our MHM products to the construction site ourselves. Our goal is to offer our customers another local product of top quality", Sterk elaborates on the company's philosophy.

Next to the actual joining work, the in-house metalworking department also manufactures all steel and welded parts necessary for timber engineering. Furthermore, the company also takes implementation planning off of the customers' hands.

With the Sterk timber house, they not only want to target timber construction companies but also architects as well as private builders in the future. "We will then coordinate all desired services and on demand establish contact with carpentries and other craftsmen in the region. MHM opens up possibilities for us to work even more across trades and plan and act more sustainably in the future", Sterk concludes.

MHM – Massiv Holz Mauer (solid timber wall)

The MHM system enables companies to independently manufacture solid timber walls and therefore build whole houses from dried, rough-sawn boards. In detail, the line consists of three working areas. In the first step, the automatic grooving and rabbeting machine mills grooves into rough-sawn boards which are subsequently flushed. This creates standing layers of air in the walls increasing the insulation value by 20% compared to conventional solid wood. From the grooved boards, the "Wall Master" makes raw wall elements of up to 4 by 6 m and thicknesses of 11.5 to 34 cm. The boards are pressed crosswise and connected with aluminum groove pins layer by layer; meanwhile the wall master is measuring the individual widths of the boards so that the nailing unit can detect every board intersection and insert two aluminum groove pins diagonally at the largest possible distance. Joining is taken care of by a PBA panel cutting machine from Hundegger.