Despite the appearance of a large number of various modern insulation materials, sawdust insulation does not lose its relevance. It is an environmentally friendly and inexpensive material with good thermal insulation, which is most often used during the construction of private houses. Insulation from sawdust can be prepared independently or purchased ready-made at a woodworking enterprise. Before using such material, it is worthwhile to study in advance the ways of using it and the installation process, which has its own nuances.
Pros and cons of sawdust insulation
Sawdust as insulation can be used to work with any elements of the house, including attic floors, floors, walls, cellars and much more. This material must undergo special processing, only in this case it will fit into the complex of construction work. All electrical cables crossing the layers of insulation must be insulated, and great attention is also paid to the thermal insulation of chimneys in those places where they pass through the ceiling of attics.
Sawdust used as ceiling insulation or for other parts of the room is divided into several varieties depending on the type of wood. The best choice is oak sawdust, which has low hygroscopicity when compared with analogues of other wood species. They are the least susceptible to the spread of rot and are not able to swell when exposed to water. In addition to oak, coniferous waste, for example, larch, pine or spruce, is suitable for thermal insulation.
The list of the main advantages of the material includes:
- increased level of environmental friendliness, since sawdust does not emit toxins;
- very low price;
- the ability to use the material in a free-flowing or other state, for example, in combination with natural or synthetic materials.
The main disadvantage of sawdust or sawdust concrete is a high level of flammability. If the material is used in combination with clay or concrete, its flammability is sharply reduced.
Scope of application
Loose material is suitable for coatings in buildings where there is a basement or insulated basement, ceilings over a cold basement and external walls. It is also used for ceilings on the upper floors, if the plans include the creation of a cool attic, or a technical floor and pitched roofs, if it is necessary to install an attic.
Walls
It is advisable to insulate walls with sawdust using waste from recycled hardwood, for example, pine, spruce, ash or oak. Oak is considered the most suitable option, albeit the most expensive. It helps to keep heat in an initially cold room, even in frosts down to -30 degrees. A good choice would be coniferous shavings, which contain a large amount of resins that repel insects or rodents. For insulation, they take sawdust of the middle fraction, since the small ones create a lot of dust, and the large ones are not able to retain heat.
Sawdust should be free of impurities and odors; for this purpose, they are dried in a chamber. The shavings with optimal humidity are dried in the air, and sawdust is never used without thorough antiseptic treatment.
Ceiling
Insulation of the ceiling with sawdust is mainly carried out using the dry method, during which the material is not mixed with binding components.The warm layer turns out to be as light as possible and does not create additional stress on the floors. Do-it-yourself ceiling insulation with sawdust in a private house can also be done using sawdust mixed with cement or clay. The procedure itself begins from the attic side, before that formwork is installed from boards with a width of at least 20-35 cm. Care must be taken that the fasteners are strong enough, since the sawdust "pillow" weighs a lot.
All wood structures are treated with fire retardants or antiseptics to reduce flammability, protect against mold, fungal organisms and rot. It is important to protect the insulator from water; for this, a layer of vapor barrier is placed on the floors, gluing the joints of the joints with tape or bitumen. Then sawdust is poured onto the vapor barrier with a layer of 20-30 cm. If the dry method is chosen, all layers are pressed and slightly moistened with a spray bottle, then after precipitation, another layer is added and sprinkled with ash. With the wet method, the insulation is allowed to dry completely within one month.
In order to properly insulate the ceiling with sawdust, you should cover up the cracks formed during the drying process with liquid clay or cement mortar.
Floor
It is advisable to insulate the floor with sawdust by mixing the raw material with lime or pouring boric acid into it in the form of a solution. For the floor, it is worth taking ordinary sawdust, since it is much easier to work with them, unlike wood concrete or sawdust concrete. The starting material is well dried, slaked lime is put into it before work to scare off rodents and insects. The filling is carried out in two layers, the height of the lower one can be no more than 10-15 cm, after it is carefully tamped.
As a second layer, sawdust dust is poured to fill the voids in the shavings, after which the final compaction is carried out. The thickness of the main layer should be at least 30 cm. It is left for 2-3 days, if it settles, you will need to re-bring the layer to the required level. In the process of warming the floor with sawdust in a wooden house, before laying the finishing layer, check for the presence of a gap for ventilation. The dry method is used extremely rarely when it comes to gender. Most often, cement or clay is added to the sawdust, which protect the material from rotting and accidental fire.
Roof
Insulation of the roof of a house with sawdust is carried out in order to prevent heat losses and provide good thermal insulation to roof structures. The material is poured into the intervals between the lags of the attic floors with a layer of at least 15-30 cm, after adding auxiliary components to it, for example, clay. The most effective option is a mixture of sawdust material with clay. To prepare this insulation, water is poured into the clay to soak. Then it is combined with sawdust in a special mixer or barrel. To achieve an ideal result, the preparation and the main stage of installation must be carried out according to the rules.
What to mix sawdust with
Sawdust cannot be used in its original form, they are capable of caking, forming empty spaces in the insulating layer, rodents and insects often settle there. An additional component disinfects the sawdust layer and makes it more convenient for installation.
Lime
Lime helps prevent the formation of pathogenic microorganisms, protects the insulation from rot and other problems. It is a strong alkali, so insects will never start in the sawdust layer with lime. It is used to prevent the ingress of beetle and rodent larvae, as well as in the form of an astringent, but as such, lime is noticeably inferior to other components. Nevertheless, it is always recommended to add lime to the sawdust layer.
Cement
Cement is not very convenient, it hardens for a day, and it is much more difficult to apply it to the wall covering. It is the most durable binder, the combination of sawdust and cement is suitable as a plaster for walls outside, filling ceilings, gaps under the floor, and as a composition for filling walls inside. After hardening, it is a loose, but solid gray stone, its color can be changed if additional coloring components are added to the original mass in the required proportion.
Clay
Clay is the cheapest binder and has many benefits. The main disadvantage is that due to the effect of water, the dried layer of the mass can become sour. In the process of drying, clay is capable of losing weight during evaporation of moisture, but in terms of strength it is practically not inferior to gypsum and cement. This is a convenient and quite plastic material that does not cause problems during installation.
Gypsum
Gypsum is no less popular due to its ability to quickly solidify, the composition based on it hardens in 10 minutes and dries completely after 2-3 hours. Sawdust insulation based on it is strong enough and weighs little, dips and cracks do not appear in it. Compositions with gypsum are not used for insulation outside without finishing, since this component is destroyed due to exposure to moisture.
The use of pressed sawdust
Pressed sawdust is suitable not only for heating, they are also used as insulation in private buildings and baths. Special boards made from wood fiber and compressed sawdust exceed standard sawdust in terms of efficiency. Antiseptics or fire retardants are always added to the material for their creation, which increase the resistance of the plates to negative influences. Their installation is carried out in a few hours, but additional coating is required for such plates.
How is styling
The process of laying sawdust should be described using the example of insulation of an attic space in a residential or utility building. During warming with sawdust, you need to weigh the pros and cons, then familiarize yourself with the technology of their installation.
First, the surface is prepared for the thermal insulation coating, the cracks are covered with clay or filled with polyurethane foam to improve the quality of thermal insulation. In the presence of a chimney, in order to protect against fire, the area around it is lined with non-combustible material, for example, slag.
For the attic, sawdust with a fine fraction is more often used, mixing them with 10% lime and 5% gypsum, first treated with boric acid and dried. All substances are combined in containers and water is added to slightly moisten the sawdust layer. Next, the solution is distributed over the entire surface of the attic with a dense layer no more than 25 cm thick, compacted and waiting for complete solidification. After that, a floor is laid on top, made of the most suitable material, which will become an ideal coating if you install it according to the rules.
