Sawdust insulation was widely used in the 60s and 70s in Western countries. But later sawdust was replaced with modern, highly effective insulation, more durable and reliable, which is easier to install.

However, it may be advisable to insulate with sawdust even now, if it is possible to “get” them for free. Until now, many organizations that process wood are ready to provide sawdust and shavings for free or at no cost; there are still costs for their transportation, for additional materials that are mixed with sawdust, as well as for the increased labor intensity of using this insulation.

But before we consider how to insulate using sawdust and shavings, let’s decide how much and what kind of sawdust will be needed for insulation, what layer needs to be created...

What sawdust and wood shavings should be used for insulation?

It should be taken into account that the larger the sawdust, the more advisable it is to insulate with it - the specific gravity and thermal conductivity coefficient are slightly lower. Also, as the size of sawdust increases, the dependence on its moisture content sharply decreases.

In fact, it is recommended to use small wood shavings, twisted into rings. It can form an elastic thick carpet filled with air with a volumetric weight of less than 200 kg/m3. It is better to leave small sawdust from sawing aside.

It is unacceptable to use small sawdust and shavings from sawing plywood, which are abundant in furniture factories and which no one needs. This plywood waste is oversaturated with formaldehyde and is not safe. Their thermal conductivity coefficient is high.

Sawdust layer thickness

The thermal conductivity coefficient of the sawdust layer is approximately 0.07 - 0.095 W/m?C, depending on the moisture content of the material, its size and packing density. For design and calculations, you can take the average value of 0.08 W/m?S.

Those. Compared to modern insulation materials (0.03 - 0.045 W/m?C), sawdust has approximately twice the body conductivity, and the thickness of their layer will be required twice as much.

For regions with the Moscow climate, when insulating the attic of a house, you will need a sawdust layer thickness of at least 32 cm to achieve optimal insulation according to the standard, and better - 35 cm. For a house of 100 sq. m. in the attic you will need a 30 m cube of sawdust, about 7 tons.

On the wall, for its insulation, there must be a layer of sawdust of at least 20 cm. Under the floor with a positive temperature - at least 26 cm, which no longer fits between the joists.

It is because of these figures that the question arises: “Is it advisable to use sawdust as insulation?” But still, the monetary savings compared to mineral wool insulation can be impressive with free material, especially if you do it yourself.

How to protect against rodents and decay

It’s probably hard to think of a better home for a rodent than sawdust. And all possible insects and microorganisms will eat sawdust very quickly. Therefore, fill them in their pure form special meaning no, the material must be treated with antiseptics. The most common and accessible is fluff lime. But it's not cheap.

Recipe for use: 20 volumes of sawdust per volume of lime. Water is added to this mixture to create a suspension and all the sawdust is saturated with antiseptics. But soap, boric acid, and copper sulfate(you can do a little of everything together for a comprehensive one, so to speak...). The material is laid wet, then within a week or two the water evaporates, and the dry, treated insulation remains in place.

Bonding the composition

Additionally, it is recommended to add two volumes of cement to this solution. As a result, after laying, the sawdust will bind together and become stronger, which will prevent their further shrinkage. When laying in vertical panels, binding sawdust with cement or gypsum is mandatory.

It is not permissible to place sawdust or wood shavings in direct contact with chimneys or similar heating structures. A fire barrier made of mineral wool of at least 30 cm is required. Electrical wiring is laid through sawdust only in a fireproof shell (in metal pipes).

How to use on floors

Sawdust and wood shavings are vapor-transparent materials, so you need to use the usual recommendations for the use of such insulation. A vapor barrier must be installed on the attic floor on the side of the house; it will reduce the humidity inside the thermal insulation layer and prevent it from getting wet in cold weather.

A ventilation gap with a thickness of 3 cm to the flooring or fence must be left on top of the layer. Typically, shavings are poured onto a vapor barrier film between the joists, then a counter-lattice with a height of 15 cm is made and the mixture is topped up, leaving the vent. gap under the top deck.

How to use wood chips to insulate walls

When insulating walls, wood shavings can be placed between the wall and the mesh fencing. If the wall is thick and made of dense materials (not a thin shield), then a vapor barrier is not needed.

A vertical sheathing is installed on hangers with a pitch of 600 mm along the thickness of the insulation - 20 cm from the wall, on which a fine fiberglass mesh is fixed.

Moistened wood shavings impregnated with cement or gypsum are gradually poured between the mesh and the wall from bottom to top in layers of 20 cm. To prevent the mesh from blowing out too much, plywood panels are used, temporarily installed on the sheathing until the insulation dries.

30 mm thick beams are placed on top of the sheathing to form a ventilation gap, after which siding or other cladding is installed.

Typical mistakes when insulating with sawdust

In this video about insulating an attic using sawdust, you can see some actions that can negatively affect the quality of insulation.

• There are gaps allowed during construction, which are sealed with polyurethane foam. But it is better not to use this foam in layers of insulation, where water vapor condenses due to temperature differences, since it is easily saturated with water and therefore collapses, leaving cracks open. Replaced with polyurethane foam glue.
• There is no vapor barrier on the room side. As a result, the insulation will become moisturized during the cold season, losing its heat-saving properties, with accelerated decomposition.
• Clean sawdust is used without treatment with antiseptics, as a result of which soon they may become putrefactive and become waterlogged.
• A layer thickness that is not optimal for economic feasibility is used - by eye, according to speculation and recommendations... - as a result, money is lost due to insufficient energy savings.

Even though V recent years A wide variety of modern insulation materials have appeared on sale; environmentally friendly waste from the woodworking industry has not lost its relevance as thermal insulation materials. It's about, of course, first of all about sawdust.

Sawdust is especially often used as insulation when building houses in regions rich in forested areas, since a large number of sawmills are usually located here. This means that it is possible to purchase material at a low price, and sometimes even find it for practically nothing.

Sawdust as insulation - “pros” and “cons”

Sawdust and materials made from it are used to insulate almost any element of the house - attic floors, walls, floors, cellars, etc. In addition, from wood waste produce blocks that are widely used for the construction of residential and ancillary buildings.

Sawdust is a waste that has a wide range of uses.

This material does not lose its popularity due to its positive characteristics, which include the following:

• One of the most important advantages can be safely called the absolute environmental purity of sawdust. They do not emit substances toxic to human health, so they can be used in any quantity.
• An important advantage is the already mentioned accessible to everyone low price material, and sometimes the opportunity to get them for free.

• Sawdust is wonderful, naturally, if the installation technology is followed correctly. If the thermal insulation layer corresponds to the required thickness, in accordance with the climatic conditions of the region, then such insulation will be in no way inferior in its effectiveness to other modern materials.

• Sawdust can be used for insulation, both in the usual bulk state and in other forms. For example, these could be slabs mixed with other natural or artificial materials.

The disadvantages of using this insulation in its pure form include high flammability. However, if sawdust is used in clay or cement mixtures, their flammability is significantly reduced.

If we think from the standpoint that the rafters, attic floors and walls are made of wood pre-treated with fire retardants, then sawdust will fit perfectly into this building complex, provided that it is also subjected to special treatment. In addition, it will be necessary to provide high-quality insulation for all electrical cables that will cross the insulation layer or be located in its thickness. The thermal insulation of the chimney pipe where it passes through the attic floor or located near the wall also requires special attention.

It should be noted that sawdust is by no means the only natural material that has been used for home insulation for a long time. And if you look at the table below, they are in no way inferior to other natural ones." thermal insulators».

Natural insulation material	Weight of material kg/m3	Thermal conductivity coefficient
Tow	180	0,037-0,041
cotton wool	80	0,036
Different felts	-	0,031-0,050
The fire is different	150-350	0,04-0,065
Moss	135	0.04
Sphagnum peat	150	0,05-0,07
Needles	430	0.08
Chopped straw stuffed	120	0.04
Straw mats	-	0,05-0,06
Fine wood shavings in packing	140-300	0,05-1,0
Dry leaves	-	0,05-0,06
Wood sawdust	190-250	0,05-0,08

Of course, not all sawdust is the same - much depends on the type and quality of the wood from which it was processed.

So, the almost unconditional “leader” in this matter is oak sawdust. They are less hygroscopic than sawdust obtained from trees of other species. Even if moisture gets on them, it will not cause them much harm, since oak contains natural antiseptic substances. Therefore, they are not susceptible to rot and do not swell when exposed to water.

However, oak sawdust is too widespread you can't call it material. It’s okay - waste from coniferous trees: spruce, larch or pine will also work well as insulation. Coniferous wood contains in abundance essential oils, steadfastly resisting the appearance of fungus or rot, that is, the very nature of the material contains antifungal and antiseptic qualities.

Preparing sawdust

Sawdust, clean, not prepared cannot be considered completely suitable for making blocks or for backfilling as insulation. After final drying, they become a very fire hazardous material. In addition, various insects or rodents may choose them to build nests.

Therefore, you must first work with clean material:

First of all, sawdust is treated with special compounds that also have fire retardant properties.

The fire retardant will make sawdust practically non-flammable...

First, the sawdust is mixed with a deep penetration antiseptic, and after drying - with a fire retardant. All processes can be carried out on a lined film a ventilated area under a roof, for example, under a canopy.

... and an antiseptic will prevent biological processes rotting, the appearance of fungus, nests of insects and rodents

• After treatment with a fire retardant, the sawdust is mixed with slaked lime, which will not allow rodents and insects to settle in the insulation.

Lime is added to sawdust in proportions of 1:5, that is, one part of lime to five parts of sawdust. The measurement can be carried out in bags - for example, pour out five bags of sawdust and one bag of dry lime, and then mix thoroughly. If the work will be done manually, then mixing can be done using a regular hoe and shovel.

• In addition, it is necessary to take into account that sawdust used for insulation in bulk form tends to sag over time, reducing the formed air gap and, naturally, losing its insulating qualities. Therefore, after a certain period, you will have to top them up or lay other insulation on top of them.

Considering this negative factor subsidence, in order to avoid the need for periodic renewal or strengthening of the thermal insulation layer, a mixture is made consisting of sawdust, lime and gypsum in proportions of 9: 1: 5. Then the mixture is moistened with water, mixed, and immediately laid on the prepared base.

Since gypsum hardens very quickly, the composition must be prepared in small portions in order to have time to place them in the place intended for them before they harden, otherwise the material will be damaged.

If you don’t want to rush, adjusting to the hardening time of the gypsum, it can be replaced with cement mortar.

When using this insulation method, pre-drying of the sawdust is not required. They can be used immediately after delivery from the sawmill.

Prices for various types of antiseptics

Antiseptics

Methods for insulating a house with sawdust

As mentioned above, for insulation using sawdust, several options for various mixtures with the addition of gypsum and cement are used, but the old one still remains the most popular folk way- composition with clay.

Sawdust with clay

Clay and sawdust are two natural materials that are absolutely safe for the health of home residents. When mixed, they form a material with excellent heat-insulating and waterproofing qualities, so they are well suited for insulating walls and. After hardening, the clay is not affected by hot steam, which cannot be said about most other modern insulation materials or waterproofing materials. Well, the sawdust in the mixture will create a good thermal insulation effect.

In addition, the clay-sawdust mixture tolerates quite well high temperatures And fireproof.

The advantages of this composition include the fact that such insulation is perfect for a house built in any region - both where the summer heat reaches critical thermometer levels, and where there are bitter frosts in winter.

A mixture of clay and sawdust not only retains heat during the cold period, but also prevents the rooms from heating up in the most intense heat, so in the house, thermally insulated This mixture is warm in winter and cool in summer.

Unlike modern insulation materials, clay-sawdust material can last for centuries without decomposing or losing its original qualities.

Insulating a building using wood waste and clay is not so easy. To achieve the desired thermal insulation effect, it is necessary carry out work in accordance with certain requirements:

• The mixture must be prepared in compliance with certain proportions, otherwise the composition will have low adhesion, and if the walls are coated with it, then after drying, crumbling is possible.

• To achieve the maximum effect from insulation, the mixture on the walls must be applied correctly and have a certain thickness.

In modern conditions, this composition is rarely used for application to walls - most often sawdust with clay is used to create an insulating layer in the attic floor, where the material will not be subjected to serious load.

If you want to insulate the walls, then it is best to make insulating slabs from clay and small sawdust or from chopped reeds or straw.

Experienced builders working with this material recommend using reeds, since for some reason it is absolutely resistant.

Plant fibers mixed with clay will become a kind of “reinforcement” for the solution, which will increase the load-bearing capacity of the insulating layer on the walls.

Preparing the mixture

There are several ways to make a clay-sawdust mixture for insulating a house. There are also several methods for laying it. Yes, from ready mixture mats can be made that are fixed to the walls and laid on the attic floor.

Another option is to spread the mixed wet mixture between the floor beams or apply it on the wall, on in advance fixed sheathing.

To produce an insulating mixture and its further use, it is necessary to prepare certain materials and tools. You will need:

• Sawdust, clay and water.
• Glassine and waterproof tape for fastening.
• A metal box with low sides (or trough) for mixing the mass.
• Large container for soaking clay.
• Bucket .
• Shovel and hoe.
• Smooth boards from which forms will be assembled for the manufacture of block panels.

In order for the mixture to be plastic and not crack upon drying, it is necessary to maintain the correct proportions of the starting materials.

A. In the event that the mass in its raw form will be laid on the ceiling or on the surface of the walls, take ⅔ of a bucket of sawdust per bucket clay diluted to creamy condition.

To obtain this clay consistency, it is placed in a large container, for example, in an old bathtub or trough, and filled with water in a 1:1 ratio. The clay is left to swell for a day or more, depending on the initial dryness of the material.

Then the mass is mixed well until smooth. If the mixture turns out to be very thick, you can add a small amount of water to it, mix well again and leave more for 5 ÷ 6 hours. To process pr It went faster, the mass needs to be stirred periodically.

If possible, it is best to soak all the clay needed for the work at once - it will not deteriorate in any way, no matter how long it is in the water. And the solution can be mixed as the previously prepared portion is consumed.

If the farm has one, then the work will go much faster. But it is most convenient to mix manually using a hoe and shovel.

To mix the clay-sawdust solution, you will need another large but shallow container made of thin metal, with sides 150 ÷ ​​200 mm high. Gets enough sleep there required quantity sawdust for one portion of the batch, and, according to the proportions, the clay mixture is laid out. Then the composition is mixed well and laid out on the prepared attic floor or applied to the walls.

B. If it is decided to insulate the house with mats made from a clay-sawdust mixture, then the materials are taken in 1:1 proportions. While the clay is swelling, during this period you need to make molds of the required size into which the finished mixture will be placed.

If the mats will be laid on the attic floor, then it is worth determining the distance between the beams and their height - the forms are made according to these parameters. They are essentially a box with no bottom.

It is best to make several molds to make several mats at once. To make the blocks even on all sides, it is recommended to do the following:

• One or more plywood sheets are laid on a flat surface, which are covered with thick polyethylene film.
• Forms are installed on top.
• The prepared clay-sawdust mixture is laid out in them and, as far as possible, compacted.
• The composition is leveled from above using a rule - in this case, the sides of the form will serve as beacons.
• After the mixture has set and dried slightly, the mats can be removed, and further drying will take place without form, in a well-ventilated place under the roof. They cannot be taken out in the sun, since upon final drying the resulting blocks may crack.
• The emptied molds are filled again with the mixture - and this continues until the required number of mats is made.

The process of insulation with clay-sawdust composition

The technology of insulation with a clay-sawdust mixture is quite simple, both with the help of mats and by laying out the mixture in a wet state.

Insulation with clay-sawdust wet mass

1. When insulating an attic floor using clay-sawdust mass, you must first prepare the surface on which it will be laid out.

• Floor boards and beams are treated with antiseptic compounds. If there are wide gaps between the boards, then glassine can be laid between the floor beams. In the case when several sheets of glassine are laid, they must be overlapped and preferably secured with waterproof tape.

• Next, a clay-sawdust mixture is laid out on the floor and leveled using a rule.

• Then the leveled surface can be moistened with water and further leveled using a spatula.
• After the clay has completely hardened, it will become dense and you can safely walk on it.

2. can be carried out in two ways - throwing a wet mixture onto the walls or pouring it into formwork attached to a finished main or frame wall.

• On the main wall, the clay mortar is applied between the installed beacons using a trowel or thrown on by hand and leveled with a rule.

• Another option is to sketch the mixture on the wall on which the shingles are fixed. But in this case it will not be possible to lay a thick layer. A clay pile of no more than 30 mm can be supported on shingles.

• After the clay-sawdust layer has dried, it is leveled with sand-cement mortar and then with plaster.

3. The third option for insulating walls with a wet mass is to lay it in formwork installed along the main walls, or fixed on both sides to frame posts.

• Formwork panels are made from boards 1000 mm high. They are fixed on both sides of the frame posts or parallel to the main wall, at a distance of 200÷250 mm from it.
• The formwork is laid sawdust-clay mixtures with careful compaction. After this, the composition is given time to dry.
• After the mixture has dried, the formwork is removed and raised higher, where it is secured again in the same way.
• The filling process is repeated in the same order until the top of the wall is reached.

• Since there will be openings on top between the frame beam or wall and the ceiling that cannot be filled using this technology, you will have to make mats of the required size, install and fix them with clay mortar on top of the finished lower sections of the walls.

Insulation of walls and ceilings with clay-sawdust mats

Sawdust-clay mats are laid in the same way as mats of other insulating materials.

• The diagram looks like this:

1 – Attic floor beams.

2 – Ceiling.

3 – Subfloor of the attic floor.

4 – Glassine is placed on the bottom and top of the insulation.

5 – Sawdust-clay plate.

6 – Finished attic floor boards.

• The preparation of floor boards is carried out in the same way as when pouring clay mass.
• Next, the finished slabs are laid on the covered surface. If large gaps remain between the floor beams and the mats, they will have to be filled with a damp mass of clay and sawdust.
• To insulate main walls, a sheathing made of a block having the size of the mat thickness (if it is not more than 100 mm) is attached to them. The distance between the sheathing bars should be equal to the width of the mat. It will be most convenient to fix the installed slabs with slats, nailing them onto the sheathing bars.
• In the event that insulation is carried out in a cold region, where average winter temperatures reach minus 25 ÷ 30 degrees, insulation boards must be at least 300 ÷ 400 mm thick. Such slabs, or rather blocks, are mounted on a clay-sand mortar, according to the principle of brickwork.

• If insulation is carried out frame walls, then it is necessary to provide for the installation of two rows of bars or boards with a thickness of at least 70 ÷ 80 mm. If two bars are installed that determine the thickness of the wall of the house, then sawdust-clay the blocks will be stacked between them. To ensure that the blocks fit tightly together in the places where the frame bars are installed, square cutouts are made in their corners, repeating the shapes and dimensions of the block.

• When main walls are insulated, it is recommended to make masonry from blocks at a distance of 70 ÷ 100 mm from the wall.
• After the insulation layer has been raised by 800 ÷ 1000 mm, it is recommended to make a backfill of expanded clay between it and the wall.
• Then the insulating wall rises another 700 ÷ 1000 mm, backfilling is done again - and so on until the very top of the wall.
• Upon completion of insulation, the walls must be cement or clay mortar.

Sawdust with cement

If instead of clay, cement is chosen as a “partner” for sawdust, then the process of making, applying or laying the mixture is not much different from working with sawdust-clay solution, but the components and proportions are slightly changed.

So, in this case, in addition to cement and sawdust, lime is required. The components are taken in a ratio of 1:10:1. Additionally, copper sulfate or copper sulfate can be added to the mixture as an antiseptic. boric acid. These components will require approximately 50 g per 50 kg of mixture. Each portion of the mass will require from 5 to 10 liters of water, depending on the method of insulation.

If all ingredients are available, mix the mixture:

• All ingredients are poured into a container prepared for mixing and mixed dry with a hoe until smooth.
• Antiseptics are added last, and after that the mixture is immediately filled with water and mixed. It will be better if the antiseptic components are diluted in water poured into the mixture - then they will be absorbed into the sawdust faster.
• The mixed mixture must be checked for readiness. This is done like this: the mixture is taken into the palm of your hand and squeezed. If water does not ooze from the lump and it does not crumble, then the composition is ready for the manufacture of slabs, for laying in formwork or for spreading over the surface of the attic floor.

On the attic floor, just as in the case of clay, glassine is placed under the mixture being laid out, but in this case it can be replaced with plastic film.

After laying the wet insulation is completed, it is left to harden.

Insulation with bulk material

Insulation with dry sawdust is quite simple. Treated and dried sawdust is simply poured onto the attic floor. The thickness of their layer varies depending on the winter and summer temperatures of the region. More precisely, this parameter can be found in the table located at the beginning of the article.

Sawdust for insulation is used dry or in the form of sawdust granules - pellets.

They are made from fine sawdust with the addition of an antiseptic, fire retardant and carboxymethylcellulose glue. The finished granules are practically non-flammable and do not harbor rodents. It should be noted that they are more convenient and practical for insulating floors than just sawdust, since they do not shrink and retain heat well.

• The granules are poured onto the prepared surface - cracks The boards are coated with a clay-lime composition, or the subfloor of the ceiling is covered with glassine.
• The granules are distributed in an even layer between the floor beams. If a layer of greater thickness is required, then sides are installed along the perimeter of the attic, with a height equal to the required thickness of the backfill layer - then the granules are laid to their top.
• If you plan to make a floor in the attic from a plank covering laid on top of insulation, then additional sheathing is fixed to the floor beams, that is, they are raised in height.

Video: insulating the attic with dry sawdust

Dry sawdust or granules are also used to insulate the walls, filling them inside. If ordinary sawdust is used, then it must be well treated with antiseptics. In addition, in order to make them heavier but maintain their low thermal conductivity, sawdust is sometimes mixed with slag. Walls built and insulated in this way reliably protect the house from the penetration of cold and summer heat.

• The insulation is backfilled as the main walls are raised by 700 ÷ 1000 mm, with obligatory, but not excessively strong, tamping for compaction.

• After backfilling and compaction, the walls are again raised to a certain height, and so the process continues until the entire required height has been reached.

⃰ ⃰ ⃰ ⃰ ⃰

Conclusion:

With proper pre-treatment, both the sawdust itself and the compositions made using them are excellent thermal insulator, which is quite capable of replacing any of modern materials. Using them, you can be 100% sure that none of your household will develop allergies or other diseases associated with the release of toxic substances, which is sometimes the problem with some synthetic insulation materials.

Sawdust is the most accessible and inexpensive raw material with a wide range of uses. These are crushed beige shavings, fine particles that are formed as a result of cutting wood. Note that sawdust should not be confused with wood chips, because they are obtained specially.

Properties of sawdust

Wooden sawdust is lightweight. Their bulk density is approximately 220-580 kg per cubic meter, it all depends on the level of humidity (standard indicators are from 8% to 15% or more). The dimensions do not exceed 50 mm, and the dry windage coefficient reaches 0.13-0.8 units.

Sawdust contains approximately 27% lignin, which is responsible for woodiness, as well as 70% cellulose, hemicellulose (actually carbohydrates). The number of chemical components is:

• nitrogen - 0.1%
• hydrogen - 6%
• oxygen - 44%
• carbon - 50%.

The main indicators, differences and characteristics of crushed wood are indicated in GOST 23246-78, which regulates this type of raw material. The same document specifies the main terms and definitions of this material.

This raw material can be called the most:

• environmentally friendly. Sawdust does not cause allergies, does not produce harmful emissions, and is completely natural
• cheap. Often you only have to pay for delivery, because most sawmills give sawdust for free, considering it waste
• heat-saving. Sawdust perfectly insulates the room from cold bridges. In this parameter it is no worse than mineral wool.

Use of sawdust

The simplest and most straightforward method is combustion, in other words, disposal. However, unlike direct disposal, when sawdust is burned without extracting any beneficial properties, today sawdust is used as a solid fuel. The use of sawdust, especially pressed sawdust, is popular due to its small volume. Pressed sawdust is very convenient to transport.

Sawdust is also in demand in gardening. IN agriculture sawdust is used quite often. They are a valuable fertilizer that improves the quality of the soil. In addition, they are used for mulching. They sprinkle the soil where seedlings are planted. All this has a positive effect on plant growth. Sawdust delays the evaporation of liquid, protects against temperature changes, prevents soil erosion, and also inhibits the germination of weeds. Various mushroom crops, such as oyster mushrooms or champignons, are often grown on sawdust.

The use of sawdust in the construction industry is also in great demand. They are created by particle boards (chipboards) and fibreboards (fibreboard or MDF). Various pieces of furniture are created from such slabs. Also, after pressing with glue, parts of the most bizarre shapes are obtained. The cost of such products is significantly lower than products made from solid wood.

The pulp and paper industry also uses sawdust. Sawdust is used to create paper, cardboard and other wood and paper materials. Deciduous and coniferous sawdust helps preserve hectares of forests, preventing the massive cutting down of trees.

The low level of density and lightness, in other words “airiness”, makes sawdust in demand as a packaging material. Sawdust filler makes it possible to protect fragile objects, for example, bottles or vases, from damage during transportation.

Strictly defined types of sawdust are used for smoking meat or fish. An excellent option for smoking are dry waste from alder, oak, beech and any fruit species. They are used separately from each other or mixed several varieties to achieve a more refined taste.

When talking about the use of wood waste as fuel for heating systems, many people see the process as quite easy: take a bag, pour the raw material into the firebox, set it on fire and get the desired temperature. However, do not forget that not all sawdust can become fuel. Key parameters to take into account:

humidity level

density of raw materials.

The efficiency of the boiler depends on these two characteristics. Research has shown that:

• fine undried sawdust from the band sawmill has a density of approximately 250 kg/m3. Their consumption per 1 kW of boiler power reaches approximately 0.5 kg per hour during continuous operation
• porous dried shavings from milling machine differs in density from 100 to 150 kg/m3. The consumption of such material will be 0.25 kg per hour per 1 kW. Therefore, for the most efficient operation of the boiler, you need to purchase the driest raw materials, because much less of it is needed than wet ones.

However, remember that the most vulnerable point of the entire heating system, built for the use of bulk waste from woodworking production, is the place for storing fuel. A boiler with a power of 25 kW in not very cold winter needs about half a cubic meter of sawdust every day, so you will need regular fuel supply, or a fairly large warehouse.

The above tips only applied to heating using bulk raw materials. But today there are technologies that make it possible to make fuel compact by pressing chips into small briquettes.

Pressed sawdust firewood releases the same amount of energy during combustion as solid wood of the same volume. At the same time, the cost of such pressed bars is significantly lower than firewood. Considering the ease of transportation, such fuel is preferable to use. Briquetting is most often carried out at the same enterprises that dispose of wood waste.

Despite the fact that the woodworking industry, as well as the wood waste processing business in Russia, has been developed for a long time, the niche is still not filled. Many methods have been developed for processing sawdust, wood chips, bark and other waste. Sawdust processing uses only 50% of the available raw materials, and in Siberia it is even less - 35%. At the same time, the remains of logging and sawmilling are not processed or used at all. Approximately 45% of wood waste is used in the manufacture of furniture. Therefore, starting a business in this field today is a profitable investment.

Table of density of wood chips and sawdust depending on the type of wood

	Bulk density of freshly shipped process chips		Bulk density of freshly shipped sawdust
Wood species	Density (kg/m3)	Limit density (kg/m3)	Density (kg/m3)	Limit density (kg/m3)
Oak	292	248-371	227	193-288
Acacia	277	234-288	215	182-225
Hornbeam	273	266-286	213	207-223
Ash	270	187-342	210	146-266
Rowan (tree)	262	248-320	204	193-249
Apple	259	237-302	202	185-235
Beech	244	223-295	190	174-230
Elm	238	202-295	185	157-230
Larch	239	194-239	186	151-186
Maple	236	205-248	183	160-193
Birch	234	184-277	182	143-216
Pear	241	211-256	188	164-199
Chestnut	234	216-259	182	168-202
Cedar	205	202-209	160	157-162
Pine	187	112-274	146	87-213
Linden	184	158-288	143	123-224
Alder	180	169-209		132-162
Willow	176	167-212	137	129-165
Aspen	169	166-198	132	129-154
Spruce	162	133-270	126	104-210
Willow	162	151-180	126	118-140
Hazelnut	155	151-162	120	118-126
Walnut	202	176-212	157	137-165
Poplar	153	140-212	119	109-165
Fir	148	126-216	115	98-168

Sawdust is the name given to waste generated in as a result of felling and processing of wood.

Despite the common name, they differ in many parameters, which determine the further use of this material.

In this article we will talk about various types sawdust and main differences, affecting their applicability for certain jobs.

Sawdust is a wood processing waste obtained as a result of its sawing.

They differ from shavings and chips:

• method of receipt;
• sizes.

GOST adopted in the USSR and the Russian Federation 18320-78 calls sawdust waste from sawing wood, but does not include waste obtained as a result of sawing:

• plywood;
• other wood processing products.

The higher:

• calorific value;
• density

wood, the more calorific the fuel from it will be.

And the higher the calorific value, the the price of such fuel is higher, therefore, the correct selection of sawdust will increase income from the production of pellets and briquettes.

Here coniferous tree species

• pine;
• larch;
• cedar.

Here hardwoods, sawdust of which is the most popular:

• birch;
• acacia;
• pear;
• apple;
• cherry.

Conifers

Softwood sawdust differs from hardwood sawdust high resin content.

Coniferous wood contains many different resins, because of this, during combustion, smoke with a pungent odor is released, therefore waste from sawing coniferous wood not used for smoking.

It is also undesirable to use them for making fuel briquettes and pellets due to:

• low calorific value;
• high ash content.

The exceptions are larch and cedar, but the cost of their wood is much higher than pine or fir trees.

For this reason, many enterprises working with wood of these species try to sell their sawing waste. as expensive as possible.

While softwoods are suitable for most applications, keep the following in mind:

1. If you use waste from sawing softwood to fertilize your garden and create compost or humus, as well as to fill paths, then add wood ash along with it, because they slightly increase the acidity of the soil. Therefore, for some plants such soil may be harmful, which will negatively affect their growth and fruitfulness.
2. If you use pine sawdust as bedding for pets, then remember - they retain a pungent odor for 1–3 weeks. In this case, the smell of pine needles can persist in a house or apartment for 4–6 weeks. If this does not bother you, then use them for bedding, but if this smell irritates you, it is better to use birch or beech waste.

Pine

A distinctive feature of pine sawing waste is general availability.

After all, pine is the main material for manufacturing:

• windows and doors;
• skirting boards and platbands;
• stairs;
• house kits;
• fences;
• sheds and garages.

Pine lumber is much cheaper cedar or larch, as well as most hardwoods, so they are widely used in:

• construction;
• various industries.

Due to its high resin content, pine sawdust not very suitable for the production of fuel pellets and briquettes.

But in regions where more suitable types of wood are not mined or massively processed, fuel is also made from pine waste.

However, they are not recommended for use in boilers and furnaces that are not designed for high ash fuels.

The waste from sawing pine is very light, almost white with a slight yellowish tint, and has a strong resinous odor that disappears after a few weeks. They are universal and suitable for most types of processing, as well as for the production of fiberboards.

Due to their high resin content, they are better preserved in sawdust-filled houses. Sawdust concrete (wood concrete) based on pine sawdust is obtained more resistant to high humidity due to the abundance of resins in sawdust. Read more about this material.

Spruce

This type of wood sawing waste is also very affordable, because spruce is no less popular building material than pine.

Spruce sawdust is darker than pine sawdust and has the same pungent resinous odor.

Pellets and briquettes made from them too leave a lot of ash after combustion, therefore they cannot be used in boilers and furnaces designed for low-ash fuel.

Very often, spruce and pine waste are mixed, because:

• logging;
• sawmill;
• in the carpentry shop

don't see the difference between spruce and pine.

Like pine sawdust, spruce sawdust emit smoke with a high resin content when burned, so in boilers and stoves with a low smoke temperature or an uninsulated chimney, fuel is made from them leads to the formation of tar condensate.

Because of this, even white (that is, consisting of wood and not containing bark particles) pellets and briquettes must be used with caution, because tar corrodes both metal and brick.

Cedar and larch

The waste from sawing these types of wood differs from the products of processing spruce and pine:

• more rich and dark color;
• special smell.

Wood of these species:

• denser than spruce and pine;
• more saturated with resins,

That's why calorific value is much higher and is comparable to the calorific value of such rocks as:

• birch;
• acacia.

Cedar and larch burn producing a large amount of ash, so they the same restrictions apply, as for spruce or pine.

Waste from sawing larch is more resistant to water, so it is not used to produce alcohol at home through natural decomposition.

Sawdust from cedar and larch is widely used for industrial production of biofuels, because chemical hydrolysis using sulfuric acid gives the same result as with any other wood.

Due to the higher:

• density;
• resistance to rot and mold

these materials, if possible to purchase them free or very cheap, are widely used for:

• insulation of houses;
• production of sawdust concrete.

Deciduous

Waste from sawing hardwood wood less accessible, because such types of wood are rarely used for construction.

Most often, hardwood is used for making:

• furniture;
• plywood;
• various finishing works.

Here main differences deciduous sawdust from coniferous:

• lower resin content;
• wide palette of colors;
• higher calorific value;
• less strong odor;
• less ash formation during combustion.

Birch

The waste from sawing birch is usually white or light cream in color.

If they are light brown, they come from old and diseased wood, so their characteristics are much worse than normal ones.

Birch sawdust is noticeably superior to spruce and pine sawdust in terms of calorific value and is on par with:

• elm;
• acacia;
• larch.

They have very low thermal conductivity, so the use of birch sawdust well suited for insulating houses.

If the sawdust is obtained from a healthy birch tree, cut in the spring and in the first half of summer, when the wood is filled with juices, then after drying it much more effectively resist any bacterial infections.

After combustion, they leave a minimal amount of ash, so they make very good fuel pellets and briquettes.

Birch sawing waste is also suitable for any other work, therefore their use is limited only by its availability, because birch is mainly used to make:

• furniture;
• joinery;
• stairs.

They suitable for any application, including for:

• supplements for hamsters and other domestic rodents;
• supplements for chickens, nutrias and small cattle;
• growing mushrooms;
• insulation of houses;
• filling paths and fertilizing the soil;
• making crafts and producing biofuel or pyrolysis gas.

Oak

The color of this material ranges from light cream to beige or light brown.

They are pointed and feel very different from:

• pine;
• spruce;
• obtained from fruit wood.

The smell of even fresh sawing waste is very weak, barely noticeable.

Oak waste – leader in calorific value. In addition, they are very dense, therefore, at the same moisture content and volume, they are heavier than most sawing waste from other types of wood.

When burned they leave little ash, therefore they are in great demand among those who produce fuel.

They are also in demand in operations such as:

• insulation of houses.

Despite the low resin content, oak highly resistant to most bacterial infections, that is:

• rot;
• mold.

Thanks to this, oak sawdust, poured between the walls of a house or in the attic, does not decompose, which is why (if it is possible to get it) they are used as insulation.

Basic limiting factor of this material is associated with the low prevalence of enterprises working with oak wood.

The use of oak sawdust is possible not only for smoking food and insulating houses, but also for:

• receiving ;
• making various crafts and wallpaper;
• production of pyrolysis gas;
• growing mushrooms;
• filling paths in the garden;
• plant nutrition;
• quality manufacturing.

Beech

The color of this material ranges from light yellow, almost white, to light brown. Because of high hardness wood beech sawdust, like oak sawdust, feels sharp to the touch, and its density is much higher than that of sawing waste from most other trees.

In terms of calorific value they are comparable to oak and when burned form a small amount of ash.

The minimum amount of resins allows the use of fuel from this material even in stoves and boilers with an uninsulated chimney, because formation of tar condensate is minimal.

Beech wood very sensitive to water and bacterial diseases Therefore, it is undesirable to use sawing waste for insulating houses without serious processing.

At the same time, beech and its processing waste are in great demand in the chemical and pulp industries due to high fiber tensile strength.

Since beech is used only for making:

• expensive furniture;
• carpentry,

Finding pure beech sawdust is very difficult.

Acacia

The color of these sawdust can be white, light green or even dark brown. Fresh sawing waste has a rather pleasant, slightly sweet, oily odor that disappears after 3–10 days.

The calorific value is comparable to larch or beech, and also when burned leave little ash, and also contain very small amounts of resins, Therefore, they are well suited for the production of fuel pellets and briquettes.

They are comparable in density to beech sawdust, but due to the lower strength of the wood, the sawdust does not feel sharp to the touch.

Due to their unusual color, such sawing waste is very in demand in various crafts, and are also suitable for creating:

• paintings;
• decorations

Due to the high strength of the fibers, they also suitable for self-made wallpaper.

Acacia is used not only as a material for making furniture and carpentry, but also as a means for:

• dividing agricultural fields into plots;
• reducing soil erosion,

Therefore, it is easier to get sawdust from it than beech or oak.

Fruit wood

The color of sawdust from fruit trees can be from light green to light brown, the smell of fresh sawing waste is weak, indistinct, depends on:

• wood species;
• places where the tree grew.

The wood of fruit trees is soft, so the sawdust feels comparable to acacia or cedar waste.

Calorific value depends on:

• wood species;
• age of the tree;
• places where trees have grown.

But on average, the calorific value is comparable to cedar and slightly lower than that of most dense deciduous trees.

• wood species;
• felling time;
• growing conditions.

On average slightly higher resin content than most hardwoods, so such sawdust is not very suitable for making fuel pellets and briquettes.

Another factor limiting the use of such sawdust– low availability, because furniture is made from fruit trees, but such wood is not used for the production of carpentry (windows and doors).

It is also not used for the manufacture of boards that can be used in construction.

Therefore, waste from sawing fruit trees most often used for:

• making various homemade products;
• home use.

Types by composition

Despite the fact that all sawing waste is clearly divided into:

• wood species;
• parts of the tree from which they are obtained,

There are situations when sawdust of different species or parts are mixed.

The value of such sawdust is determined by their composition, for example, pine-spruce sawdust from industrial wood is no different from good pine or spruce sawdust.

When cutting unbarked logs, waste with a high bark content is obtained, so their calorific value is lower and their thermal conductivity is higher.

Sometimes such sawdust, like fuel pellets or briquettes made from them, are called “gray”. Therefore, when choosing sawing waste for any work it is necessary to clarify their composition, this applies to sawdust from any type of wood.

When choosing sawdust, it is very important to pay attention to the absence of foreign additives.

For example, at a sawmill you can collect material that will contain:

• pieces of earth;
• leaves;
• dried branches.

On a sawmill, if a band saw is installed in it, the material will be high content of machine oil, so it can only be used for heating or insulation.

Mulching the garden with such sawdust will only lead to soil pollution and reducing its yield for many years.

Where is it used?

We have compiled a short list of things that can be made from sawdust and attached to it links to relevant articles in which this or that method of application is described in more detail:

1. Fertilizing the garden, filling paths, mulching and protecting plant roots from the cold.
2. Supplement for rabbits, chickens and small cattle.
3. Additive for hamsters, birds, dogs, cats and small livestock.
4. Growing mushrooms.
5. Smoking of various products.
6. Crafts, papier-mâché and appliqués.
7. Homemade stylish wallpaper.
8. Insulation of walls, ceilings and floors.
9. Production of fuel pellets and briquettes.
10. Production of sawdust concrete and wood concrete blocks.
11. Biofuel (technical alcohol).
12. Pyrolysis gas suitable for use in heating boilers and cars.

You can read more about these and other ways to use sawdust in this article (Using sawdust).

We have compiled a table from which you can find out what types of sawdust used for certain operations and actions.

We included everything in the table the most famous methods the use of sawdust, as well as white sawdust of various types of wood. To ensure that all types of sawdust fit into the article, we replaced them with the initial letters of the species names:

• A– Acacia;
• B– Beech;
• Br- Birch;
• D– Oak;
• E– Spruce;
• TO– Cedar;
• L– Larch;
• P– Fruit trees;
• WITH- Pine.

In addition, we used gradation of effective use from 1 to 5, where 1 – cannot be used due to extreme negative consequences, and 5 – provide the best result when applied.

Application	Wood species
	A	B	Br	D	E	TO	L	P	WITH
Heating with sawdust	5	4	5	5	1	1	1	3	1
Production of fuel pellets and briquettes	5	4	5	5	2	2	2	3	2
Creation of sawdust concrete	5	4	4	5	5	5	5	3	5
Insulation with sawdust	4	3	4	5	5	5	5	4	5
Use in the pulp and chemical industry	4	5	5	5	5	5	5	5	5
Paper making	5	5	5	5	5	5	5	5	5
Filling paths in the garden	5	5	5	5	5	5	5	5	5
Mulching plants	5	5	5	5	4	4	4	5	4
Creating humus	5	5	5	5	5	5	5	5	5
Growing mushrooms	5	5	5	5	5	5	5	5	5
Home production of biofuel and alcohol	5	5	5	5	4	4	2	5	4
Industrial production of biofuel and alcohol	5	5	5	5	5	5	5	5	5
Production of pyrolysis gas	5	5	5	5	3	4	4	5	3
Creation of fiberboard, chipboard and other building materials	5	5	5	5	5	5	5	5	5
Supplement for hamsters and other pets	5	5	5	5	3	4	3	4	3
Bedding for chickens, rabbits and other animals	5	5	5	5	4	5	4	5	4
Use for making crafts	5	5	5	5	5	5	5	5	5
Smoking	5	4	4	4	1	1	1	5	1

Useful video

In this video you can see how the type of sawdust affects the quality of sawdust concrete:

Conclusion

To choose correctly sawdust for certain jobs, you need to clearly understand how they differ.

After reading the article, you learned about:

• various types of sawdust;
• qualities that distinguish one type of sawdust from another.

In addition, you found out what properties do they have various types sawdust and for which jobs they are better suited than others.

Recently, construction companies have increasingly begun to pay attention to sawdust, which accumulates in large volumes, both in production and during the construction of buildings. Recently, sawdust has been used not only as an additive to the composition of building materials, but is also the basis of some of them. You won’t surprise anyone with a house whose walls are made of wood concrete slabs, and the foundation is insulated with economical sawdust concrete.

Use of sawdust in everyday life

Concrete screed is quite expensive for home owners, especially with a large living area. You can save money by adding sawdust to the solution in the optimal proportion. Experts recommend making this type of screed in two layers to ensure high-quality thermal insulation and maintain strength properties. The bottom layer does not take significant mechanical loads and is resistant to external factors, but must provide low level heat loss

To do this, add the standard two parts of sand to one part of cement and an additional six parts of sawdust. The resulting mass is placed directly on the ceiling and blocks possible cold bridges. The second layer of screed is laid on top. Here, instead of six, only three parts of sawdust are used to ensure that the surface of the screed achieves the required hardness and abrasion resistance.

The financial benefits from using such a screed are enormous. After all, 70% of it consists of sawdust, which can be bought for next to nothing at woodworking or furniture factories. Often they are simply thrown away due to lack of a market. Plus, the sawdust in the screed acts as a heat insulator, the need for which automatically disappears.

Sawdust in building materials

It is becoming increasingly common to see sawdust used as a concrete filler. The result is the so-called “sawdust concrete”, which is used for monolithic pouring of building frames. This type of monolithic structure is much cheaper due to the saving of expensive high-grade cement. Just one part of it accounts for four parts of sawdust, which in turn provides heat and sound insulation of the walls.

An even more affordable sawdust-based thermal insulation material is wood concrete. A higher quality mixture is made with the addition of cement, while a budget mixture replaces it with clay or lime. The use of such material at this stage is the most profitable in comparison with analogues.

Related materials:

In order to neutralize impurities that cause metal corrosion, there are rust converters. These substances can prevent further development of the process...

Now we can observe a situation where corrugated sheeting is becoming more and more popular every day. This is due to the wide possibilities of its application. Corrugated sheeting is...

There are quite a few types of equipment designed to move goods. The most common devices used to perform these tasks and...

The progress of many areas of science and industry has also affected the construction sector, in which new techniques are constantly being developed. For example, constructing buildings using...

If in old buildings only swing doors were used as entrance and interior doors, today there are many ways to open the door: folding doors, swing doors...