The use of local materials reduces the cost of building private houses. Slag insulation improves the energy efficiency of the home and reduces heating costs in winter and air conditioning in summer. Slags of different types differ in properties. This is taken into account in the design and construction.
Environmentally friendly slag
The material in question is production waste. Understanding whether slag is harmful as a heater is important already at the beginning of designing a house.
The insulation technology and the place of use of the backfill do not provide for direct contact with a person. Dust and gaseous emissions do not penetrate the rooms, therefore they are not able to harm health.
When buying, you need to require a security certificate. Some slags emit a radioactive background.
Types of material
The following types of insulation are obtained from the waste of metallurgical production and the energy industry:
- domain;
- metallurgical;
- fuel and coal.
Different types are used to insulate the structural elements of the house.
Domain
The material is obtained by smelting pig iron. The composition includes the remains of rocks, fluxes and fuel ash. The pieces are very porous, the material is free-flowing.
In private construction, the small (heavier) fraction is used for filling cavities in the walls or for screed concrete floors. The coarse fraction - light in weight - is suitable for filling attic floors.
This type of raw material is used for the manufacture of slag insulation materials.
Slag pumice, which has good heat and sound insulating properties, is most suitable for insulation. She also goes to the filler for cinder blocks.
Metallurgical
This type often includes waste from nickel and copper smelters, steel plants.
The material consists of sintered pieces of various fractions. They contain a lot of metal oxides, which is why the mass of the composition is large.
Metallurgical waste is more suitable for dumping tracks, parking lots. The high specific gravity and excessive thermal conductivity limit the use of the material for insulation, creating a large load on the foundation and building structures.
Fuel
The raw materials for the production are the remains of fuel oil and coal burned in boiler houses. Fraction and properties depend on the type of combustion (chamber or layer).
Fuel residues are hygroscopic, therefore, before backfilling, they must be dried for at least 2 months without being exposed to precipitation.
It is used for filling cavities in brick walls or under a concrete screed on floors and ceilings.
Advantages and disadvantages
Despite the difference in technical characteristics, all types of slags as insulation have similar positive qualities.
The material is different:
- ease of use;
- low cost;
- optimal air exchange;
- resistance to decay, fungus formation, mold spread;
- the ability to use in any premises;
- mechanical strength and chemical neutrality;
- inaccessibility to damage by rodents and insects;
- good indicators of thermal conductivity compared to monolithic concrete or brick;
- unlimited use time, subject to installation technology;
- fire safety.
The structure of the material imposes restrictions on the application. The high specific gravity is taken into account when designing load-bearing structures.
Slags are less effective in relation to modern specialized products for thermal insulation - polystyrene, foam insulation, mineral plates, etc.
Industrial waste is not used to insulate surfaces exposed to precipitation, or concrete screeds are applied over the backfill to protect against waterlogging. Wet slag loses its insulating properties.
Metallurgical type is susceptible to rust in high humidity conditions.
Industrial types of insulation are hidden with a screed or filled into the voids of the brickwork to prevent the ingress of harmful substances into the air of residential premises.
Specifications
The parameters of different types of backfill for comparison are collected in the table. The data are averaged, but sufficient for correct calculations of the mass and the effect of insulation.
| Slag type | Specific weight, kg / m3 | Thermal conductivity, W / (m * C) |
| Domain | 360 - 1000 depending on the faction | 0,12 – 0,18 |
| Boiler house, coal | 750 | 0,24 – 0,32 |
| Fuel | 1000 | 0,25 |
| Metallurgical | From 1000 | 0,35 -0,4 |
The thermal conductivity of solid silicate brick is 0.81 W / (m * C). Thus, a layer of coal slag with a thickness of 20 cm in terms of insulation properties is approximately equal to a masonry of 2 bricks (51 cm). Taking into account the difference in price, the developer significantly reduces the cost of materials.
Thermal insulation technology for building structures
Heat engineering calculations and instrumental measurements show that 5-10% of the heat leaves the dwelling through the floor and soil, 20-30% through the walls and the same amount through the attic floors and the roof. Slag insulation can be used for these building structures.
The sequence of work to improve the thermal insulation characteristics for the floor, ceiling, walls is different.
Floor insulation
Depending on the design of the dwelling, floor insulation with slag in private houses is carried out in different ways. If, in the spring and after heavy rains, water appears in the basement, the basement must be waterproofed.
Brief instructions for warming an earthen floor:
- The surface is freed from debris, leveled, tamped if necessary.
- Equip waterproofing, for which the floor is covered with clay, dissolved in water, and thoroughly mixed to a dough state. Another option: a layer of waterproofing roll material is spread, the joints are glued with mastic.
- A layer of insulation of the required size is carefully poured - the thicker the better. For most regions, it is enough to add 15 - 20 cm.
- Pour 5 cm of sand, ram.
- Pour a cement-sand screed (DSP) 5 - 10 cm.
If the height of the ceilings in the basement does not allow you to equip such a "cake", you can fill the floor with concrete, using slag as a filler. Before pouring, arrange a sand pillow, which is spilled with water and rammed.
An option is possible when it is not the earth base that is insulated, but the insulation is poured over the floor slab on the first floor. In this case, heat is obtained in the rooms and a cool basement.
The sequence of work is simple:
- They remove debris, dirt, dust.
- Cracks and technological holes are sealed with cement mortar.
- The stove is treated with an antiseptic to prevent mold and mildew.
- Cover the surface with a layer of vapor barrier film (membrane), which will prevent the penetration of vapors from the basement, but will allow moisture to evaporate into the underground room. In houses with dry basements, a vapor barrier is not required.
- DSP is performed on top of the heat insulator layer.
- After drying, they are finished with finishing materials (laminate, chipboard, linoleum).
To insulate wooden floors, the top layer is dismantled. Waterproofing is laid between the lags, on top of which slag is poured. On the upper surface of the lag, a vapor barrier and a counter-lattice are nailed. The thickness of the slats is 1 - 2 cm.It forms a layer of air between the fill and the flooring, which will prevent the formation of mold and mildew.
Ceiling insulation
Technologically, the work on floor and ceiling insulation does not differ.
Before insulating the ceiling with slag, it is necessary to carry out calculations so as not to overload the structures. To do this, you need to find out the bearing capacity of the floor slabs and compare it with the mass of the backfill.
Slag as ceiling insulation has the same pros and cons as when used in other building structures.
The height of the non-residential attic allows you to pour a layer of any required thickness (taking into account the characteristics of the slabs). The insulation will retain its properties throughout the entire life of the house.
In order for the slag for ceiling insulation to retain its properties, precipitation should not fall on it. The dormer should not be closed tightly - this will help the moisture evaporate in a timely manner.
Insulation sequence:
- Floor slabs are covered with a layer of waterproofing.
- The required amount of backfill is filled in.
- Equip a concrete screed with a thickness of 10 - 15 cm, observing the slope for draining water during precipitation.
- Waterproofing is carried out with roll materials.
In order for the coating to last a long time, the instructions of the manufacturers of building materials are followed.
Insulation of hollow walls
Insulation of walls with slag does not require special preparations. Any slag is poured between the outer and inner layers of the brick as the walls are being built. It is better to choose a porous material of the middle fraction. Such characteristics will make the house warmer, there will be no voids between the pieces of backfill.
Warming houses using the backfill method does not require special skills and the purchase of expensive equipment. In settlements where the material is a waste of local industries, thermal insulation will be the cheapest and easiest option.
