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Common reed

Common reed

A grass species (Phragmites australis) with creeping rhizomes and dense panicles, purplish or yellowish in color; it is almost cosmopolitan, commonly found along the banks of ponds and watercourses, where it often forms dense reed beds.

A humble grass, which grows spontaneously in marshy areas, along streams, lakes, and the rivers, harvested by humans and used like a construction material since the Paleolithic era, for its properties and benefits. Today, in green building, the stems of the common reed, tied together in mats (known as arelle or reed) or compressed into panels, are used as roofing layers, plasters support and as thermal-acoustic insulation materials.

Features:

Durability
Thermal insulation
Breathability and moisture resistance
Enviroment impact
Acoustic insulation

Applications:

Roofing layers
Plaster support
External insulation
Internal insulation

Breathability (μ)

2-5

Ability of a material to be passed through by water vapor
To prevent condensation and mold: the lower the value, the better the internal moisture regulation
Thermal Conductivity (λ)

0,053-0,056 W/mK

Indicates a material ability to conduct heat.
To prevent against cold: the lower the value, the better the insulation performance
Specific Heat Capacity (Cp)

1.200-1.500 J/KgK

The amount of heat to raise the temperature of a substance by one degree.
To prevent against heat: the higher the value, the slower the material heats up
Density (ρ)

150-190 Kg/m

How is the mass of a material distributed in the space it occupies
To prevent against heat: the higher the value, the better the material’s capacity to resist heat

Durability

Common reed has proven extremely durable over time, both in indoor and outdoor uses, likely due to high silicon content. it grows in water and, as a result, is not affected by humidity and resist decay. In Sweden and other parts of northern Europe, we find examples of roofs made entirely from reed mats that are about 80 years old, lasting longer than many modern roofing materials.

In the interior application, durability is even greater due to lower exposure to the elements. This is evidenced by 15th-century Italian buildings with reed-and-plaster ceilings that remain in excellent condition.

Thermal insulation

The Bio-Architecture Office of the Piedmont Region includes common reed among the fibrous plant-based insulating materials with excellent thermal conductivity values.

Common reed has a thermal conductivity slightly higher compared to some other insulation materials, but it stands out for its moisture resistance.

Even in high moisture environment, thermal conductivity remains stable, unlike other materials that deteriorates or lose effectiveness over time.

Breathability and moisture resistance

As a natural material, reed ensures breathability, preventing the formation of vapor water condensation that can damage masonry, and cause mold or rot.

Thanks to his breathability and moisture resistance it is widely used as a support for plasters including frescoes surfaces and is still employed in the restoration of damp walls.

Environmental impact

At all stages, from processing to application, reed does not release any toxic substances, whether chemical (e.g. VOC), or microbiological like bacteria or mold, it is odorless and non-radioactive. It also is electrostatically neutral, meaning it does not promote buildup of static electricity on its surface.

Applications

The most common applications in green building are roofing layers that serve both as insulation and as a covering and external thermal insulation and plaster support.

Reed mats

Held together by galvanized wire or nylon mechanically applied, called also “arelle” or “cannicciato” or “reed matting”, they are used as a support for plaster layers, especially in combination with indoor plaster realizing by natural materials as clay, lime o “cocciopesto” (crushed pottery plaster).

Pressed reed panels

With thicknesses from 3 to 10cm, they are used to create insulating layers both thermal and acoustic and are usually finished by a plaster layer. They can be used for internal or external insulation systems, inside wooden walls or structures, for suspended ceilings and even for partition walls.

Composite blocks in lime and reed shiv

Increasingly used like construction materials due to their excellent insulating and hygrothermal properties, as well as their ease of installation.

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Common reed

Features:

Applications:

Durability

Thermal insulation

Breathability and moisture resistance

Environmental impact

Applications

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