Specific nuances of insulating the walls of a building with straw, positive and negative aspects of using this material, surface preparation, the main stages of thermal insulation, final finishing with siding panels. Insulation of walls with straw is a popular and recognized worldwide method of thermal insulation, which is distinguished by safety and high environmental friendliness. In recent years, this technology is gradually spreading on the territory of the post-Soviet space. In addition, special construction skills are not required for thermal insulation of a frame house.
Features of thermal insulation of walls with straw
Straw of various crops is used as a raw material: wheat, barley, rye, oats. First, the stems are dried in special heat chambers, after which they are pressed to a state of the desired density, tied and packed. Only after that, the raw material becomes a material suitable for thermal insulation work. You should not try to prepare raw materials on your own, because ordinary field straw can be affected by fungus and insect larvae.
Another important point is the correct strapping of each bale. Metal wire is not suitable for these purposes, as it will rust over time. Most often they are tied with a nylon or polypropylene cord. If the bale is tied correctly, then there is no way to even stick two fingers under the cord.
The material is produced in the form of blocks compressed under pressure in a special apparatus called a baler. The size of the blocks and their density will depend on its settings, which usually ranges from 80 to 100 kg / m3… The average weight of each product is approximately 16 kg, and the finished compressed block usually has dimensions of 50x40x100 cm.
If you want to insulate the walls with straw, you need to carefully approach the choice of material. Particular attention should be paid to the quality of the pressing. The blocks should keep their shape well, not deform under pressure. The thermal insulation properties, the stability of the insulated walls and a number of other characteristics will depend on the quality of the pressing. Since the qualities of this material are fully revealed only in compressed form, therefore, only carefully compacted straw is used for installation work.
One of the most popular methods of warming is the use of clay together with straw. This technology has proven itself well for thermal insulation of walls, roofs, ceilings. The process of applying this solution is simple and does not require a lot of time, but it is imperative to allow the insulated surface to dry, and this can take at least a month, even at positive ambient temperatures.
Advantages and disadvantages of wall insulation with straw
Let's highlight the following strengths from the use of straw as insulation:
- Despite its apparent fragility, straw is more durable and stronger than wood due to its increased silica content.
- As a porous material, it has high sound insulation characteristics.
- It has a low thermal conductivity and a high coefficient of heat transfer resistance.
- Resistant to biodegradation.
- Economical due to its low cost.
- The undoubted plus of the rammed blocks lies in the practicality of their use: in case of significant damage, a fragment of the block is simply cut out and replaced with a new piece.
- With a moisture content of no more than 20%, it is not subject to decay processes.
- The material has the ability to "breathe", which means that it can not only absorb moisture and harmful substances, but also return them back.
- Unlike a number of other heat-insulating materials, straw does not lower, but, on the contrary, increases a person's energy by 10%.
- The material that has worked out its operational resource is easily disposed of by burning or using it as fertilizer for the garden.
- Straw blocks can be easily and quickly cut with a chainsaw.
- Straw easily maintains favorable indoor climatic conditions.
- Insulated buildings significantly reduce energy consumption, which, as practice shows, does not exceed 38-40 kWh per square meter per year.
- The low weight of this material greatly facilitates installation work.
Consider the possible negative qualities from the use of this insulation. It is believed that straw itself is a highly flammable and combustible material. However, this does not apply to bales that are covered with plaster according to building standards. They are able to withstand up to 2 hours in open confrontation with fire.
The criterion of the durability of this insulation also depends on a number of subjective factors. For example, was the straw removed from the field correctly, where and how it was stored, how well it was packed and processed. Failure to comply with any of the requirements will lead to a deterioration in thermal insulation properties.
Rodents can start in the straw because it creates favorable climatic conditions. But this only happens if it was not sufficiently compressed and not treated with plaster or slaked lime.
Note! When working with such insulation as straw, a large amount of waste is necessarily generated. They must be cleaned up in a timely manner, do not smoke nearby, and have a portable fire extinguisher on hand.
Straw wall insulation technology
Insulation of a multilayer wall with straw consists in the alternate installation of thermal insulation layers made of clay, as well as straw sawdust. In order to ensure the long-term operation of the insulation, you first need to prepare the walls.
Preparatory work before fastening the straw
Before starting the insulation process, it is imperative to prepare the surface of the outer wall. At this stage, we must conduct a thorough inspection for cracks, irregularities or deep seams. The surface is carefully cleaned from traces of old coating, finishing materials and dirt. Large indentations are manually sealed with filler mortar.
For filling, you can use conventional gypsum mixtures, which are inexpensive and do not shrink much. In stores you can find ready-made putties that do not have to be diluted with water and kneaded. But they are more expensive than dry ones and have a much shorter shelf life. Puttying is carried out either in 2 layers, or use a painting net for this, on which the solution fits perfectly.
If there are protruding parts or dry plaster residues on the surface, they can be knocked down with a hammer and chisel. After that, the wall should dry well, otherwise moisture will destroy the insulated insulation.
If there are areas of accumulation of moss and mold, then after removal, they must be additionally treated with bioprotective drugs. Otherwise, residues of substances can grow through the insulation.
Now you can proceed to priming the surface, which will provide good adhesion properties. The primer is applied either with a roller or with a paint spray. To calculate the volume of the required substance, you can use the instructions indicated by the manufacturer.
Before you start applying the primer paint, be sure to protect all areas that should not be painted: doorways, windows, steps, blind area and plinth. For this, ordinary plastic wrap is quite suitable.
For thermal insulation, we need such tools: a regular pencil, a ruler, a hammer, a plumb line, a jigsaw, a level, a screwdriver, containers for putty and paint, paint brushes and rollers, sandpaper of varying grain size, a fine sieve, a folding ladder, dry rags, a chisel, spatulas, usually.
The following must be prepared from materials and consumable components: sand, cement, briquetted straw, dry clay, siding panels for finishing, ground paint, putty, screws or nails, bioprotective and antiseptic solutions.
Straw Wall Mounting Instructions
The step-by-step algorithm will be expressed in the following actions:
- First, a vapor barrier is arranged on the walls. A plastic film is taken as a basis, which will protect our insulation from getting wet and condensation accumulation. Pieces of the film are cut according to the size of each cell from the installed crate.
- The working mixture is kneaded from clay and straw in a ratio of 2: 3. To do this, it is convenient to use a metal trough, a boil or a large basin. Water must be added until the consistency resembles sour cream.
- The finished mass is laid out on boards already covered with a vapor barrier material. The layer is made 2-3 cm, after which it should dry completely.
- If we find cracks after complete drying, then they need to be repaired with the remains of liquid clay.
- When the clay insulation finally hardens, it becomes covered with dry sawdust, straw, shavings. A layer of 5 cm is enough.
- If dry compressed straw is stacked, then this should not be done in a chaotic manner. Experienced installers calculate in a special way the optimal angle at which the fibers are located, which will reduce heat loss to a minimum.
- It is advisable to build a wooden flooring on top of the insulation. A board made of any well-dried wood is suitable for him. It is stuffed onto the mounted lathing so as to completely cover the frame.
Surface finishing
This stage largely depends on what kind of insulation was carried out - outside or inside the house. For exterior decoration, you can use one of the following options:
- Brick cladding, which immediately gives the building respectability and solidity. But before such a choice, you need to make sure that the walls and foundation can withstand the mass of brickwork.
- Finishing with a wagon board, which has an attractive appearance and is also easy to assemble.
- Siding trim, which is a set of metal or vinyl panels. They can be made in any color according to the wishes of the owner. They are necessarily mounted on insulated walls.
Let's take a closer look at how to decorate a heat-insulated building with siding. This technology is not only famous for its aesthetically pleasing surface appearance, but is also considered environmentally friendly. It is distinguished by its strength and durability, has a relatively low cost in relation to other finishing works.
Siding begins with the installation of the sheathing. If it is made of wood, then it is advisable to impregnate it with an antiseptic composition. Another option for manufacturing the lathing is the use of a galvanized profile. The fastening of the slats must be vertical, since a ventilated gap must be left between the wall and the cladding. The slats cannot be interconnected with horizontal bridges, because it is thanks to the free circulation of air that we can protect the insulated walls from the appearance and growth of fungus or foci of mold.
After we have finished plastering the walls with clay and straw, the siding panels can be closed. This material can change its shape under the influence of moisture and temperature extremes, so the panels do not need to be nailed tightly. They should be left with space to shrink or expand, otherwise they may warp.
Nails are driven into the pre-prepared mounting holes strictly at an angle of 90 degrees. If the panel is installed correctly, then it will be able to move to one side and the other within the width of the hole. As soon as we take the next siding panel for fastening, we first click the lock, and only then proceed to fix it with nails or self-tapping screws. Weak tension will necessarily lead to poor fit of parts.
After all the panels have taken their place, they begin to install the outer and inner corners. They are necessary in order to hide the edges on the adjacent walls of the building. After that, you can put the edging of doors and windows. All that remains is to remove the scraps of material, and the insulated, siding house is ready.
How to insulate walls with straw - watch the video:
With proper observance of building technologies and the rules of careful operation, straw-insulated walls can last for more than a decade. The process of warming itself is not laborious, so it can be done with your own hands.
