Low wall (architecture)

A low wall in architecture is a Mur of dry stones or a built wall.

The role of the low wall in the biodiversity of the garden

There exist various installations making it possible to support the development of a specific flora and a fauna at home, the construction of a low wall (dry stone wall or built wall) in fact part.

He proposes a vision different from the garden (deprived, public, of company, etc), so that he becomes a garden with positive Biodiversité.

The installation of a wall (as of a stone heap) can allow the installation of a diversified wild life which will find a refuge of quality if one takes some precautions in his realization.

A whole miniature world survives it and hides there.

The low wall constitutes a point of observation and discovered considerable for the urban naturalist. During the day, the wall absorbs the heat of the sun, which it restores during the night, a little with the manner of a radiator with accumulation. Many insects come to be heated there, benefitting not only from the direct rays, but also from the heat which emanates from the stones

One can thus find a quantity of insects there (spiders, wasps build, etc), of reptiles (lizards, grass snakes, vipers, etc). Even the birds and the small mammals can find refuge there.

For the plants, being given the nature of the low wall, one finds plants adapted to the dry climates (lichens, foams, ferns, etc).

All these species, animal and vegetable, will be different according to the exposure and from the orientation of the low wall. One will be able to even find species very different on each side of the wall…

To build a low wall

One distinguishes two types of walls:

the Wall of dry stones.
the Wall built.

For the biodiversity, construction is carried out by using traditional materials and processes; indeed the walls of traditional invoice are to be avoided because their smooth and uniform walls are not very accessible for fauna and the flora. The absence of small cavities, anfractuosities and point of anchoring in fact very often of the sterile mediums. The use of materials to the irregular structure like the stones or bricks is thus recommended in order to give to the wall a whole ecological potential. The use of a mortar containing lime, or stones limestones, supports obviously the presence of calcicoles vegetable communities. Conversely, one will be able in an area rather given to privilege the silicicolous groupings on other materials.

The stone wall dries

the orientation
Unless it is not a retaining wall, the wall has two faces. In order to maximize the specific variety of the animals and plants which will colonize it, one will be able to choose an orientation which makes it possible to have two exposures to the sun and the dominant winds very different.

the foundations
For a wall a height from 1 to 1,5 m and 0,8 to 1,20 m of width, one will be able to envisage foundations between 20 and 30 cm of depth. These sand foundations and gravels or small well packed stones will make it possible to ensure the stability and the drainage of the work. One will be able to cover them with a layer of large stones for more solidity.

the stones
the chemical nature of materials is also a big factor. One will be able to use stones out of sandstone or out of limestone, that will support in particular the presence of calcicoles communities. The stones punts will be appropriate better, it will pile up easily.

One can then assemble the wall on a height from 1 to 10,5 m, with a slope from 10 to 20% to ensure the stability of the work.

One can fill the space ranging between the two rows of stones by sand (favorable to the laying of the lizards).

The built wall

To build a built wall, one will be able to use the same technique as for the dry stone wall and to use a mortar made up of an extinct air lime bucket (lime CAEB or flower) for three fatty sand buckets.

If the wall provides a function of supporting, to prefer a mortar made up of a lime bucket for two of stream sand. At certain places, one can put ground instead of mortar.

Installation

To supplement the stone wall advantageously, one will be able for example to associate nesting boxes to him (nesting boxes with insects, birds or chiroptères,…)

See too

Biodiversity in the frame and the garden
Fifteenth target HQE
Pierre dries
Mur vegetalized
Nichoir

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