A return to partially neglected construction technologies is associated with the tendency to use natural materials. They give homes a natural coziness and have good environmental qualities. A classic example of such buildings are adobe houses, the main material of which is a mixture of clay and straw. Buildings gained their popularity for their environmental friendliness, natural climate control in the room and the relative ease of construction.
What is adobe house?
Analogs of modern houses made of straw and clay existed in ancient times. Some of them have survived to the present day - in the arid regions of Asia and Africa, you can find whole adobe cities. Improvement of construction technologies has led to the widespread distribution of clay buildings in central Europe and modern Russia. Properly built clay houses have more than a century of operation and are safe for residents.
Visually adobe buildings are not always different from ordinary ones, although their main “charm” is the ability to give the walls an arbitrary shape and adapt to home furnishings. Numerous excavations, bathtubs and smooth transitions strikingly distinguish clay buildings from brick and other block-cement structures.
Old technologies are rarely applied in their original form, since the operational parameters of modern houses are increased through the use of modern additives. Natural fire-fighting properties of clay, prone to baking at elevated temperatures, are improved with the introduction of components that increase the strength characteristics.
Adobe construction technology
1. Materials to be stocked up in advance:
- wooden planks and bars for the construction of the frame of the walls and roof;
- clay;
- sand;
- straw;
- water (well or centralized water supply).
Additional materials that are useful in the preparation and finishing stages include:
- gravel - for preparation of bedding under the foundation;
- material for the manufacture of solid or brick foundations;
- flat wooden planks for upholstering the walls of the house;
- wooden (metal) formwork or form for the manufacture of blocks.
Although the house will be clay, its foundation is better to make a classic - tape. Strong and elevated above the ground base will increase the life of the house and reduce the impact of melt water on the lower part of the walls.
A place for construction should be selected away from the lowlands and exit to the surface of the groundwater. The optimal location of the clay house is on a hill.
In order to get the most durable building suitable for our latitudes, it is better to make walls by pouring mortar into the formwork. You can also use clay blocks, which are stacked similarly to the classic block designs.
A significant reduction in the cost of construction is achieved through self-extraction of clay on its site. Small amounts of straw are cheap, and the largest costs will be associated with the purchase of sand and lumber.
The straw must be dry, without rot. It is best to buy it immediately after the harvest season, and then leave it for the winter in a dry and ventilated area.
2. Preparation of the solution
Many authors advise not using pure clay, but its mixture with sand. Since clay and sand differ in composition for different regions, we can test their different proportions (2: 1, 1: 1, 1: 2, etc.). The clay-sand mixture, to which water is added until a doughy consistency is obtained, should be clenched in a fist and dropped onto a solid foundation from a height of 1.5-2 m. A lump of suitable composition should not crack or collapse strongly when dropped.
To prepare the solution, you can use a concrete mixer or a flat base with the edges bent up (mix the solution with your feet). Clay is crushed to a finely divided state, after which sand and water are added to it. The latter should not be much so that the mixture retains a highly viscous consistency and does not flow out of the formwork.
Straw is added to the resulting clay-sand solution in an amount of 30 to 60%. The more straw, the lower the thermal conductivity of the walls and their strength (will have to be limited to one floor). The resulting solution is poured into the formwork, exposed along the edges of the wooden frame of the house.
The frame is assembled from beams and is a vertical and horizontal guides. There should be a blank for the roof above, since after pouring the walls, you must immediately start covering it. The solution is poured in steps (up to 30 cm per day), after which the wall should be allowed to dry. With self-construction, the wall usually "grows" by 10-15 cm in one day cycle.
Outside, the walls are covered with a crate of straw or reed - they create an additional insulating layer. The crate is attached with a thin layer, which is pressed against the wall with wooden flat strips (nailed to wooden supports). Outside, the crate is covered with clay or lime plaster.
The use of lime plaster is optimal, since it prevents the appearance of parasites inside the walls.
3. Roof made of straw and clay
On top of the roof frame upholstered with boards, bundles of straw are laid, which are then leveled (the rope fastening them is cut). The straw is fixed in the same way as the crate on the wall - with wooden slats. After covering the roof, you can proceed to coating it with clay-sand mortar.
The process is carried out from the lower edges of the roof to the ridge. After hardening, the coating will not allow moisture to pass through, but it will leave the room the opportunity to “breathe” and maintain humidity at an optimum level of 50-55%.
Feature: roof pouring should be done alternately and evenly on both slopes to avoid skewing.
4. Wall decoration
Inside the house, upholstery is made of wooden planks, which are then plastered. Unlike clay plaster, wallpaper can be glued on top of the lime (they will not be damaged by parasites). Clay plaster can not always protect against the appearance of insects, but it is cheaper.
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What is the difference between modern houses and old buildings?
To give additional tensile strength to the clay solution (straw partially copes with this), cattle manure was widely used before. The same solution plastered the walls of the room, called the "hut." The main disadvantage of such houses is the abundance of insects in the walls.
Now, natural chaff and bonfire are used to increase strength. A couple of centuries ago it was difficult to get them, and now it is the waste of plant processing.
An increase in strength and a decrease in shrinkage during drying increases the addition of crushed stone or expanded clay. An auxiliary element is sand. To increase the speed of solidification, cement or lime can be added to the clay-sand mortar. Their additives are used during construction in wet weather, with the goal of reducing the risk of wetting of still wet wall material.
Casein, starch and water glass help to increase the viscosity of the solution during operation. The latter is an antiseptic, therefore, additionally prevents the appearance of mold and insects.
The use of modern construction technologies, including the sublimation of a strong foundation, increases the strength and stability of the building. Instead of a clay roof, you can lay out the usual ruberoid coating, which is closed on top with slate or tile. This will not degrade the environmental properties of the house, but will improve performance.
To protect the house from rodents, it is necessary to provide for the presence of a thin metal mesh under the crate.
Features of care for thatched houses
A separate point in the operation of buildings is fire safety. Clay houses with a coating of the outer and inner surfaces with clay or lime mortar are less prone to fire damage than ordinary ones. When a flame occurs, the straw in the composition of the walls does not ignite, since the air is closed to it by a layer of clay.
Despite the high fire resistance of the walls of adobe houses, the wooden parts of the roof do not possess it. To reduce the likelihood of fire, consider treating wood with flame retardants. They do not provide absolute protection against fire, but are very effective when observing the application technology.
Construction companies involved in the construction of houses made of clay and straw assure the practical impossibility of the appearance of insects in the walls. This is true only when maintaining low humidity, which is not always possible. Do not neglect the advice to use lime plaster, which clogs the walls to access moisture and will inhibit the development of insects.
Before building a house, consider the location of the stove and bathroom. In places of contact with heated surfaces, reflective screens must be placed and waterproofed in wet places.
Pros and cons
Advantages of adobe buildings:
- clean and healthy "atmosphere";
- indoor is cool in summer and warm in winter;
- low cost of building materials;
- relative simplicity of construction.
Disadvantages of straw houses:
- construction cannot be carried out in winter;
- when damp, insects start to wall in the walls, which “gnaw through” the wallpaper;
- weak strength in hurricane winds (less important in rough terrain).
It is not necessary to magnify the durability and safety of clay houses, however, they should not be minimized either. An adobe house is ideal for a summer house or as a summer house on a personal plot. A properly built clay house will stand no less than its predecessors, but it will give more pleasant sensations and health.