DD18 Module - Lorenz Straw Building

Product description DD18

The DD18 module is available as a wall, roof, floor, ceiling and gable module. Its construction depth is 18cm. The low specific weight (24.9 kg/m2) allows for simple superstructures with lighter foundations. The DD18 is available with frame thicknesses of 45 mm.

Construction method

wooden frame construction, hand-made prefabricated wooden frame
machine pressed and shaved straw infill

Assembly

quick and easy to assemble
can be plastered or paneled immediately
sizes adjustable (up to 4-fold in width)

Environmental aspects

completely biodegradable and recyclable
wood and straw store CO₂
tested free of harmful substances

Building physics parameters DD18

Straw quality: construction straw, regional origin
Fire behavior: E (normal flammability)
Bulk density straw: 100 kg/m3 ± 15 kg/m3
Straw moisture content: <18%
Compression type: mechanical pressing of small bales into compartments
Straw orientation: stalk orientation perpendicular to heat flow

Wood quality: spruce dried, planed, untreated
Bulk density wood: 420 kg/m³
Wood moisture: <15% ± 3%

Dowel bars, beech untreated, 8mm
Pan head screw, galvanized, 6 x 140 mm / 6 x 160 mm
Spruce cross bars, pre-sorted 24 x 24 mm

Thermal conductivity value (λ): Construction straw 0,049 W/(m*K), Softwood 0,130 W/(m*K)
U-value (without cladding): 0,289 W/(m²*K)
spec. heat storage capacity straw: 2,0 kJ/(kg*K)

Product advantages and
special features DD18

Walls open to diffusion with good insulating properties, easy assembly, combined with a small construction depth – all this is offered by the DD18. Coated with clay plaster, it shows its advantages especially in smaller buildings, where every centimeter and low weight matter the most.

Phase shift: 8.3 h

Straw has a heat storage capacity of 2 kJ/kg*K. Heat is only lost very slowly to the outside. A time delay of the heat transport takes place. With a construction depth of 18 cm, this slowed-down heat transport corresponds to 8.3 h.

Specific gravity: 24.9 kg/m²

Due to its low specific weight, the DD18 module is ideally suited for pile, screw, point or strip foundations. The DD18 module is ideal for buildings where the optimum of heat-cold protection, useful area and safe integration into the site are sought.

Per m² stored CO₂: 30 kg

The production of the renewable raw material straw binds far more CO₂ than is required for transport and further processing. Each square meter of DD18 module installed binds 30 kg of emissions into the building structure – much like a CO₂ vault.

Infill width: 62.5 cm

The infill width of DD modules corresponds to the common grid dimension in timber frame construction. As other building materials also conform to this dimension, waste is reduced. Overall, this dimension simplifies planning and handling during construction.

3 products in one

DD modules are wall, insulation and plaster base in one prefabricated element. This reduces costs and planning effort. Depending on the coating, the shell can be closed directly after delivery and assembly. Breathing walls are achieved with natural materials.

Plane surface

The high dimensional accuracy of machine-guided production at LORENZ enables smooth surfaces that do not need to be reworked on the construction site. This simplifies construction, saves time and makes assembly uncomplicated.

Realized projects with DD18

A straw lodge overlooking the lake

Built on a steep slope, the sauna house harmonizes perfectly with the natural surroundings. With a view of the lake, the builders enjoy a healthy indoor climate during the sauna session.

DD18