Warm wooden house calculation wall thickness and cutting angle features

Wood is one of the most common building materials to the land of centuries-old history. Wood build houses, baths, churches, erecting luxury cottages and temporary structures. Widespread prevalence and availability of wood, this material provides increased attractiveness to developers.

Our portal has in detail told, from which wood is better to build a houseand differs from conventional corrugated board. We continue this series of articles.

Calculation of log wall thickness and diameter of the log

Whether heat in a wooden house, if the diameter of the logs is 25, 30, 35 cm or more. This is - one of the main questions that should ask themselves any developer, planned to build a house or from debarked logs. Agree that it is unwise to build a log house, if later it turns out that the wall thickness is not enough to comfortably survive the harsh winter. Insulate the house from the outside or from the inside - is not an option: all will be gone aesthetics logs. It remains hard to heat a log house and increase energy expenditure or pre-calculate a sufficient thickness of the walls in relation to the region of residence.

In one of our previous articles, we have talked in detail, how to calculate the thickness of insulation for the stone house. At first glance it seems to do the calculation for log home is simple - it is necessary to find the required thermal resistance normalized wall (R) in your area of ​​residence. To do this, we find this information on the Internet. For example, for simplified calculation (For Moscow and Moscow region) take R = 3.0 (m² * ° C) / W.

Now we need to know the actual value of the thermal resistance of the wall, which is composed of a certain diameter logs. After that we will be able to learn (on the basis of calculation), if heat resistance compliance. To do this, use the following formula:

R = d / λ, where:

d - the thickness of the material;

λ - thermal conduction coefficient of the material (W / m · ° C).

Herein lies the first pitfall. wood Thermal conductivity coefficient (λ) is presented in the following table:

As you can see, there are three values. Which one to take, and what is meant by "normal" and "wet" conditions?

Hermes-sz (User FORUMHOUSE):

Thermal conductivity coefficient of the material (including a heater) is largely dependent on its moisture content.And the operational humidity of the material depends on the climate zone and the mode of use of the premises.

For example, the thermal conductivity of pine and spruce (dry) across the grain (the thermal energy of the wooden house comes out across the logs) is 0.09 W / (m · ° C). Under normal operating conditions (A) and during operation in a wet zone (B) the thermal conductivity of the material increases and is 0.14-0.18 W / (m · ° C).

If waterlogged material increases its thermal conductivity and decreases the thermal resistance of the structure. Therefore, For the calculation, take the following value: wall material - pine, thermal conductivity material (the averaged value under normal operating conditions) - 0.15 W / (m · ° C).

In most cases, heat conduction coefficient of materials and insulants indicated in the dry state, i.e., obtained in laboratory tests, which differ from the actual operating conditions. This should be remembered, producing an independent calculation.

So, wood thermal conductivity, we have understood. It remains to choose the thickness of the wall to which you want to make the calculation. And here lies the second pitfall. Logs are stacked on each other, i.e., a slot. Moreover, depending on the log diameter (D), customer requirements, is changing the groove width (H), and hence the actual width of the assembly in relation to the thickness of the log. This relationship is depicted in the following figure.

It can be seen that with the same diameter logs, depending on the design features of a node logs abutting width of the groove can vary. So just substitute in the above formula of the thickness of the timber can not be selected. We need a common denominator that can be used for the calculation. To solve this problem we use the experience of the user with the nickname of our portal zaletchik.

zaletchik (User FORUMHOUSE):

I want to live in a log cabin. There is no gas in the area, and is not expected. Region of residence - Moscow region. So - an urgent need to reduce the cost of heating. Heat the house going to the boiler, operating on diesel fuel. These inputs have forced me to study the thermo-physical properties of the carcass.

At first zaletchik counting teploharakteristiki log, calculating the average value of the thickness of the partition structure. This approach was not entirely correct, because heat loss is considered to be directly proportional to the thickness of the wall. As a result of brainstorming and communicating with FORUMHOUSE users zaletchik I made a correct calculation.

zaletchik:

To properly calculate the thermal conductivity of the walls of the house chopped I calculated thickness log of timber, having the same insulation properties as the frame of a particular log diameter (D).

Leaving outside the article details the calculations, which can be found in topic reflection and speculation about the thermal conductivity log, Go straight to the obtained coefficients, which we need for the calculation.

For different values ​​of ε (H / D the groove ratio of thickness to diameter logs) Are calculated corresponding values ​​μ (* D Heff the ratio of thickness to diameter timber logsHaving the same heat-conducting properties). The results are summarized in the table.

For clarity, consider the following example. Suppose the diameter of logs used in the construction of log - 45 cm. Groove width - 23 cm. Hence: ε = 23/45 = 0.5. Now we find in Table μ value corresponding to the received digit. This is - 0.83. Next, find the thickness of the wall of the timber folded in relation to the log diameter, having the same heat-conducting properties: 45 = 0.83 * 37.4 cm. Translations into meters - 0.374 m.

Given this figure, we can now calculate the thermal resistance of the wall, built of logs. For this substitute values ​​obtained in the following formula:

R = d / λ, where:

d - the thickness of the material;

λ - thermal conduction coefficient of the material (W / m · ° C). In this embodiment, logs of pine - 0.15 W / (m · ° C).

R = 0.374 / 0.15 = 2.49 (m² * ° C) / W

Or, you can use this formula:

R = μD / λ, where:

μ - coefficient is taken from the table above;

D - the diameter of the beam in meters;

λ - thermal conductivity of wood.

R = 0.83 * 0.45 / 0.15 = 2.49 (m² * ° C) / W

Previously we have indicated that for Moscow and Moscow Region R = 3.0 (m² * ° C) / W. Based on the result obtained, for walls, folded from pine logs, R = 2.49 (m² * ° C) / W. Those. wall does not reach the regulated values ​​of thermal resistance. You can increase the log diameter or choose a different wood - cedar pine. The thermal conductivity of this material (log diameter and groove width leave unchanged) - 0.095-0.10 W / (m · ° C).

We make the calculation.

R = 0.83 * 0.45 / 0.10 = 3.74 (m² * ° C) / W

Ie, the rate of the actual resistance to heat transfer is blocked.

You can go the other way and use a different formula to find the desired diameter of the log of the ratio: width of the groove in poldiametra logs.

D = Rtp * λ / 0.83, where:

Rtp - regulated thermal resistance of the wall;

λ - thermal conduction coefficient of wood;

We do the calculation for pine.

D = 3.0 * 0.15 / 0.83 = 0.54 m.

Using this method and "playing" with different values ​​- by varying the diameter of the log, the width of the groove, wood - can be made independent calculations and choose the optimum thickness of a log wall houses.

zaletchik:

My great-grandfather and grandfather were specialists in the construction of log cabins, logging and wood processing. From them I learned of the required slot width of 1/2... 2/3 of the diameter of the log.

Also on the thermal efficiency of the log wall it affects not only the width of the groove, but timber profile - its section: round or the so-called polubrevno, hewn from two sides - flitches. Skived wood, we reduce the thermal resistance of the wall, because beam in the wall running all of its cross-section.

Of course, the results of this simplified calculation for orientation. Most of the heat loss in a home occurs through the windows, ventilation systems, roof and foundation. Those. Warm wooden house - this is a balanced system where all the components work closely together and meet each other. No reason to make a wall of logs with a diameter of 0.4-0.5 meters and choose a slot, if the house is blown through the gap, and the angles are frozen.

Features log cabin

To choose the best option cabin log home and thus make it warm, you need to understand what options exist cuttings, and how they differ from each other. First you have to define concepts such as vrubka and crown.

Hermes-sz

Notching - a connection log various wooden parts together.

With proper notching load evenly redistributed between the logs. To do this, all wetted parts must fit tightly to each other. Also in these areas should not accumulate moisture, which over time can cause rotting of the wood.

Crown - a log building house, consisting of four logs stacked in a horizontal plane. In the corners of the crown associated notching. During the construction of the house crowns stacked on top of each other - it turns out the wall.

It should be remembered that the diameter of the logs and the groove width depends on the number of crowns, which affects the flow of the material, and thus - the final price and the thermal properties of the framework. For example, for the construction of wall height of 3 meters from a log diameter 25 cm and 40 cm will need a different number of crowns. When building a house of a larger diameter of the log decreases the amount vrubok, castles, mezhventsovogo connections. Those. Places, which can then be purged, resulting in heat loss.

Masters work with large diameter log harder physically. crane - the use of special equipment may be required.

In addition, the choice as a construction material debarked logs are mindful of this parameter as a taper.

taper - the difference in the thickness of the beam in a ratio of the diameter of the butt and tops. Debarked log is not elapsed, unlike logs, machining may not be completely smooth. Its lower part (especially with a large length of the log) is always thicker than the top. That the wall was obtained even in the construction of chopped home master at laying of wreaths, a series of different thickness logs.

Cutting itself can be divided into two types:

• Without the rest (in the leg).
• Since residue (in the bowl).

Felling without a trace, or in a clean corner involves maximum utilization of the full length material.

With such a cutting turns at right angles, which increases the useful area of ​​the house and reduces timber consumption. But, on the basis of practical experience, we can say that this kind of angle is subject to freezing. To avoid this, even in the old corners of the house, cut down "in a paw" trimmed overhead boards, or as an option, then obkladyvali house brick. This prevented freezing and blowing angles.

Chopping with the remainder - more expensive, but also more heat-effective option. Because ends of logs appear at the corners of the house, this node more protected from blowing, pouring rain and freezing.

Leaving the scope of this article all the variety of different types of cutting, focusing on the key features of the three main types of log cabin. It:

• Russian felling;
• Canadian cabin;
• Norwegian cabin.

In our country, the traditional wooden houses are built of round logs. Along the timber is semi-circular groove. Corner notching lock is in the "Oblomov" in the bowl. The name comes from the word "obly", ie round. The cup may be positioned up or down.

If the cup is down (cutting bowl "in coir"), such a connection is more water resistant, and the beam is better preserved.

Hermes-sz:

The main disadvantage of Russian cutting is that the logs dry out the length and breadth of fibers differently. As a result, after shrinkage log in securely seated in the wooden house.

When reducing the beam diameter is changed form the connecting bowls. Bowls open and semi-circular from becoming oval. There are gaps. As a result of felling is necessary caulk more times. In addition, the outdoor heater is exposed to adverse weather conditions. He saturate with water, and logs can start to rot.

This deficiency deprived frame made in Finnish. The principle is the same as that in Russian wheelhouse, except that in this embodiment mezhventsovogo groove is of smaller radius (zaovalen). Thus, the upper beam is supported only on the lower edges (undercut).

As a result of shrinkage of logs mezhventsovogo edge of the groove are not disclosed, the logs are sitting tight, no gaps, and insulation is not exposed to wind and rain.

Norwegian cabin. Traditionally, the frame in Norwegian - is the log carriage, although the main difference - is the type of lock.

Hermes-sz:

The main difference between the Norwegian castle from Russian cup is that the Norwegian castle has a tapered (trapezoidal) profile.

Due to this structure, when desiccation timber sags under the weight of the log in the log structure and is wedged into the lock. This provides strength and integrity notching.

Canadian cabin similar to the Norwegian castle, but there are differences. Bowl in a trapezoid shape, are cut in a round log, doing zatosy side and in the lower part of the log is cut barb. Accordingly, in the upper part of timber cut groove Studable overlying timber.

Mezhventsovogo compound is similar to the Finnish version - undercut. When shrinkage upper log log abuts on the bottom.

No cracks, mezhventsovogo heater is buried, and the walls are log look like a single array.

Also, there is no need to re-caulking.

In addition, the Canadian log cabin using the so-called Equipment zaveshivaniya angles. The ends logs located outside the log and an inner array (located in the heat in the house) have different moisture. Logs are exposed to temperature changes. As a result, due to the different degree of shrinkage, the corners and the central portion of carcass can "hang". Gap is formed between the logs, and the frame will be purged and freeze.

To prevent this, the outer corners of "post", ie between the ends of the logs that are outside, leaves more clearance than the inside.

As a result, after the log cabin sits down, the gap along the entire length equalized logs.

Log house - it is a time-tested method of building a beautiful and environmentally friendly homes. To get high quality results, you need a balanced and thoughtful approach, as well as close monitoring of all phases of construction.

The topic wooden houses FORUMHOUSE your question and get a comprehensive answer can be set. For a quick search the answer to any question related to the construction of a wooden house, We recommend to use a special navigator. Also recommend that you read the article, how to deal with pests of wood, and what features have roof system wooden house.

can be found in our movies about features chopped home, and take a virtual tour of the chopped bath called "Fairy Tale".

Discuss the article and read other materials devoted to country life you can on the websiteFORUMHOUSE.

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