Recommendation points
- Construction of a wooden attic floor
- The choice of material for insulation
- Bulk materials
- Piece materials
- Features of work on laying thermal insulation on a wooden floor
The attic floor separates the heated part of the building from the cold one. Choosing the right material and the thickness of the insulator means reducing heat loss and saving material costs during the heating season. Let’s talk about insulating the attic floor on wooden beams with our own hands.
Construction of a wooden attic floor
The load-bearing elements in the attic timber floor are beams. They are made from softwood. The size of the section of the beams is taken according to the calculation for the load that the element takes. We told you about the correct calculation of wooden floor beams in the article “How to calculate wooden floor beams”.
For each specific climatic conditions and depending on the ability of the material to resist heat transfer, according to the heat engineering calculation, its own thickness of the heat insulator is obtained.
Attic floor insulation scheme: 1 – lag; 2 – cranial bars; 3 – board board or boards; 4 – vapor barrier; 5 – counter lattice for the ventilation gap; 6 – insulation; 7 – clean floor; 8 – ventilation gap
The subfloor made of wooden boards or planks is mounted on cranial blocks. Next, a membrane-type vapor barrier is laid, insulation is laid on it, which is covered with another layer of membrane.
If the attic is in use, a clean floor is laid on top. If not, then running boards (min. 40 mm thick) are placed on the beams. All wooden elements are antiseptic. To ventilate wooden structures when laying a clean floor, a gap is left between it and the insulation.
The choice of material for insulation
Bulk materials
Expanded clay
It is possible to insulate the attic floors with bulk materials, which include expanded clay. It has a relatively low weight (250-600 kg / m3) and high resistance to heat transfer. Ease of installation and relative cheapness determine the choice of this material..
Vermiculite
Expanded vermiculite is obtained by heating a vermiculite rock to a temperature of 700 ° C, which increases in volume by 25 times. Its thermal conductivity ranges from 0.13 W / m K, and its bulk density – up to 200 kg / m3.
Perlite
Expanded perlite also belongs to bulk thermal insulation materials. Perlite rock is crushed and burned to obtain a porous structure. Expanded perlite is environmentally friendly, does not burn and is bio-resistant, has high thermal insulation properties (0.052 W / m · K). Its volumetric weight is 160-250 kg / m3.
Piece materials
Piece insulating materials are manufactured in the form of: sheets, rolls, plates, mounting shells and segments. Plates and rolls are most often used to insulate the attic floor. At the same time, roll-type insulation is preferable, since it does not leave butt seams, which slightly, but worsen the resistance to heat transfer.
Basalt wool
Mineral wool slabs and rolls of basalt fibers are the most popular thermal insulation material in housing construction. It is made from crushed and molten basalt by blowing. Basalt wool has low thermal conductivity (0.32–0.048 W / m · K), low volumetric weight. This material is bio-resistant, environmentally friendly and relatively inexpensive..
Glass wool
Glass wool is very similar in its characteristics to mineral wool. It is also obtained by melting the starting material, which in this case is glass breakage. Glass wool has longer strands, greater chemical resistance and strength, lower cost than mineral wool.
It is produced in the form of plates, mats, rolls, reinforced and with a reflective layer. The volumetric weight of glass wool is from 25 to 200 kg / m3, heat assimilation – 0.035–0.045 W / m · K. The disadvantage of fiberglass is the need for personal protection during installation.
Expanded polystyrene
Polystyrene foam (polystyrene) also belongs to plate heaters. It is a cheap, lightweight, moisture resistant material with good thermal insulation properties. In private housebuilding, it is often abandoned due to rodent damage and low resistance to high temperatures..
Extruded polystyrene foam
Extruded polystyrene foam (penoplex) has good insulation properties, is less fire hazardous than simple polystyrene foam, but when burned, it emits toxic substances.
Polyurethane foam
Slab polyurethane foam (foam rubber) has a high resistance to heat transfer (0.029–0.041 W / m · K) and a low volumetric weight (30–80 kg / m3). In construction, rigid types of this material are used. The sprayed polyurethane foam creates a continuous surface insulation, both heat and hydro. It is also resistant to temperature extremes and durable in operation (up to 20 years).
Foam glass
Foam glass is a type of glass that has a cellular structure. It has low thermal conductivity (0.04–0.08 W / m · K), waterproof, high strength and fire safety. The percentage of porosity of foam glass reaches 80–95%. The volumetric weight varies from 100–200 kg / m3.
Peat slabs
Organic thermal insulation materials include peat slabs. They are made from young sphagnum moss using a wet and dry method. Peat fibers stick together under the influence of temperature. Peat slabs are subdivided into ordinary and moisture resistant. Their volumetric weight is 170-300 kg / m3, thermal conductivity coefficient – 0.05–0.07 W / m · K.
Fiberboard plates
Fiberboard boards are made from wood fiber, which is first subjected to mineralization and then mixed in the required proportion (cement – water). Thermal insulation boards have a lower volumetric weight (300-350 kg / m3) and thermal conductivity (0.085–0.95 W / m · K) than constructive fiberboard.
It is quite possible to make a fibreboard mixture yourself and lay it directly into place. You can first use a special technology in the formwork to make slabs of the desired size from it, and then mount them on the floor.
Reeds
Reed is also used as a heat-insulating material, which is practically the cheapest. It is made from compressed reed stalks sewn with steel wire.
The volumetric weight of reeds is 175-250 kg / m3, heat assimilation coefficient – 0.05–0.08 W / m · K. Its disadvantages are low fire resistance and biostability, high water absorption and damage by rodents..
Ecowool
Ecowool (cellulose wool) belongs to environmentally friendly thermal insulation materials. It is made from recycled cellulosic raw materials with the addition of antiseptics and fire retardants. Most often they are boric acid and borax.
In stores, you can find it packed in plastic bags. When laying, ecowool is loosened and then laid out at the place of insulation. In fact, the density of the insulation should be at least 35 kg / m for the overlap.3, which is quite difficult to determine “by eye”.
This heat-insulating material has good thermal conductivity values - 0.037–0.042 W / m · K, small volumetric weight (28–63 kg / m3), moderately flammable and bio-resistant. Ecowool can not allow about 20% moisture to pass into the inner layers, while maintaining its thermal insulation properties.
Cork insulation
Cork boards for thermal insulation have been used for a long time. They are made from crushed waste of cork production by mixing with glue or heat treatment. Pressed boards in special forms are dried at a temperature of 80 ° C.
The volumetric weight of cork insulation is small and amounts to 150-250 kg / m3, the heat-insulating index is high (0.04–0.08 W / m · K). The advantages of this insulator include:
- biostability;
- low water absorption;
- low volumetric weight;
- relatively high strength as a heat-insulating material;
- fire resistance (smolders slowly);
- not affected by rodents.
Features of work on laying thermal insulation on a wooden floor
Insulation made of mineral and glass wool is laid with mandatory vapor barrier. By absorbing water, the insulation loses its thermotechnical properties, so careful protection from moisture is needed. Vapor barrier films are laid with an overlap of 100 mm.
A heat insulator with a reflective coating reduces the heat loss of the floor. It is laid down with the foil. The use of penofol is justified only in baths and saunas.
If the thickness of the insulating material is greater than the height of the floor beams, it is necessary to install additional battens to create an air gap. Multilayer thermal insulation is arranged with overlapping butt joints.
The dimensions of rigid insulation boards are adjusted with great care so that the gaps do not increase the thermal conductivity of the floor. Otherwise, the installation of this type of insulation does not differ from the thermal insulation device made of mineral wool slabs.
Bulk heat insulators are evenly distributed over the entire space between the beams, observing the required (calculated) layer thickness. Since they almost all absorb moisture, such an insulator is protected from moisture by a membrane film from above and below..
The choice of material for thermal insulation of the attic floor is due to the following criteria:
- Material costs including shipping costs.
- Local material availability.
- Ease of installation.
- Health safety.
- Fire safety.
It is possible to reduce the stress of the building structure by choosing a heater with a lower volumetric weight and a low heat absorption rate.
What are some key factors to consider when insulating an attic floor using wooden beams?
When insulating an attic floor using wooden beams, there are several key factors to consider. Firstly, it is important to determine the appropriate type and thickness of insulation material to use based on the climate and desired R-value. The material should be placed between the wooden beams, ensuring a snug fit to prevent air leakage. Secondly, it is crucial to consider the vapor barrier. Installing a vapor barrier on the warm side of the insulation can prevent moisture buildup and reduce the risk of mold and rot. Additionally, attention should be given to air sealing. Properly sealing all gaps and cracks can minimize heat loss and maintain energy efficiency. Lastly, it is vital to consider the accessibility of the attic space. Ensuring easy access for maintenance and repair purposes should be kept in mind when insulating the attic floor using wooden beams.
Can wooden beams be a suitable material for insulating an attic floor? Are there any advantages or disadvantages in using them? What other types of materials can be considered for attic floor insulation?
Wooden beams themselves are not a suitable material for insulating an attic floor. They lack the ability to provide adequate thermal resistance. However, wooden beams can be used as a structural base to support other insulation materials. Some advantages of using wooden beams include stability, durability, and ease of installation. Nonetheless, disadvantages include potential for heat loss/gain, limited insulation value, and the need for additional insulation layers. Other insulation materials commonly used for attic floors include fiberglass batts, cellulose insulation, rigid foam boards, and spray foam insulation. Each has its own advantages and disadvantages, so the choice depends on factors such as the desired R-value, budget, and accessibility.