Lithuanian residents interested in log homes and saunas should first familiarize themselves with the style of log buildings, structural forms, log (wall) profiles, and corner joint types.
Key concepts, terms, and definitions:
Wall log (Sienojus) – a log of varying profile and dimensions, processed by hand or machine, forming part of the building’s wall structure.
Corner joint (Kampų sujungimas) – the interlocking area of the building’s wall logs, commonly referred to as a notch, joint, corner, or lock.
Longitudinal groove (Išilginė išdroža) – a long continuous groove running the entire length of each wall log, traditionally called pazu or pozu.
Log projections (Rąstų išsikišimai) – the short end portion of a log extending beyond the corner joint (notch).
LOG BUILDINGS ARE CLASSIFIED ACCORDING TO ARCHITECTURAL STYLE, TYPE, OR STRUCTURAL FORM:
1. These are buildings whose wall structures use hand- or machine-processed logs of various profiles and dimensions, laid horizontally one on top of another, incorporating a continuous groove and connected at the corners with joints of different forms.
2. These are buildings whose main load-bearing wall structures use hand- or machine-processed logs of various profiles and dimensions, assembled both vertically and horizontally. These are known as “Post and Beam” or, in Lithuanian, “Stulpiniai-Sijiniai/Log Structures.” In such buildings, wall, floor, roof insulation, and finishing elements are installed between the vertical posts and horizontal logs. This construction method was originally applied in North America, particularly Canada. Very large logs are used for the structural elements. Choosing this style gives residential exteriors a striking appearance, as massive wood is combined with various finishing materials, while the interior conveys warmth and coziness.
3. These are hybrid buildings, where each floor can be constructed differently. This refers to horizontally stacked logs combined with a “Post-and-Beam” system within the same building. This style is very popular in Norway and is called “StavLaft.” It can also be combined with masonry, half-timbered frameworks, and other architectural styles.
4. These are buildings whose wall structures typically use machine-processed, double (paired, with an air gap) milled logs or beams (wall logs), with thermal insulation materials placed between them.
5. These are buildings where the wall structures of the same floor are hybrid, combining a stable (load-bearing) insulated frame from the interior, while the exterior is clad with log-imitating beams or real logs (wall logs). This is more of an exterior visual style rather than a true log building style. However, it is mentioned because there is public interest, and it is sometimes mistaken for genuine log homes.
LOG BUILDING WALL STRUCTURE LOGS (WALL LOGS) ARE CLASSIFIED BY SHAPE AND PROFILE:
1. Logs (wall logs) made from natural tree trunks, round in cross-section, of varying diameters, processed by hand. These logs must be prepared exclusively by hand, as the surface needs to be free of defects, which is difficult to achieve even with the most advanced machinery.
2. Logs (wall logs) made from natural tree trunks, machined on two sides (rectangular in shape), of varying thicknesses and heights, but finished by hand. Commonly referred to as “lafetas” in everyday language.
3. Machine-processed, milled or turned logs (wall logs) of various profiles and dimensions, in round, rectangular, square, trapezoidal, or elliptical shapes. The raw log is shaped using multifunctional machinery. When constructing buildings with machine-processed logs, the longitudinal groove and corner joint nodes are also typically formed with the help of computerized machinery, though exceptions do occur.
4. Glued laminated timber (glulam), machine-processed, milled or turned logs (wall logs) of various profiles and dimensions, in round, rectangular, square, trapezoidal, or elliptical shapes. For these building walls, dried timber pieces are glued together. The name of the wall log itself indicates that the shape, longitudinal groove, and corner joint nodes are formed using multifunctional, computerized machinery.
WALL LOG SURFACES CAN BE:
- Hand-hewn, made using a curved axe called a “skliutas.” Do not confuse this with machined logs, which some people mistakenly call hand-hewn. Machined logs can later be processed with a skliutas to achieve a hand-hewn appearance. Traditionally, round logs were hewn with a special axe to create a rectangular shape, which is the origin of this term.
- Planed, using hand planes or hand/electric planes. The log can also be planed with a shaping plane equipped with specially shaped blades, giving the wall log surface the appearance of being hand-hewn or textured with wave-like patterns.
- Sanded, using orbital, belt, angle, hand, or electric sanding tools. Rarely, logs can also be sanded with machinery.
- Aged / Textured, using special hand or electric tools for aging and texturing (with brushes) or sandblasting.
- Machined, refers to logs prepared using machinery. Their surface is immediately planed, as the logs are calibrated during processing.
- Machined, refers to logs prepared using machines. Their surfaces are planed immediately, as the pieces are calibrated during processing.
Another characteristic feature of log buildings, probably the most important, is the corner joint, also called the lock (spyne).
- Saddle notch at the bottom log, with protrusions. Also called a joint with protrusions. This is probably one of the first and most commonly used notches in the earlier period of log building. Especially in Russia, when constructing churches and temples, this corner joint was used in the late 19th and early 20th centuries.
There are two types of “saddle notch at the bottom log.” The first – simply an open rounded bowl-shaped notch. The second variant – the same notch but with a cut (wedge).
Craftsmen working with the bottom log saddle notch say one of the advantages is that when logs dry, cracks often appear in the lower part of the log, which can split the log itself. With the bottom log saddle notch, this problem is largely resolved. Advantages include – simplicity and ease of execution, as well as warmth.
The disadvantage is supposedly that it is not a long-lasting notch. Since moisture enters more quickly between the joints, which are directed upwards. However, this depends on the caulking (insulation layer). As we know, such notches were often made and flax was used for caulking. The density of its application influenced protection against moisture entering the gaps between the logs. Despite concerns about longevity, in the previously mentioned Russia, buildings constructed 200–300 years ago used the saddle notch at the bottom log.
2. Saddle notch, top log cut, with protrusions. Also called a joint with protrusions. It is considered that this notch is more resistant to moisture than when cut in the bottom log. One disadvantage is that wood dries unevenly along and across the grain, and after the logs have dried, they do not fit evenly, sit unevenly in the saddle, and stretch, changing from round to oval, creating gaps. This requires additional caulking, and as is known, open insulation material is affected by moisture.
The saddle notch in the top log is simpler and easier to make quickly because only one log is processed, unlike the bottom log saddle where processing involves three logs.
Scandinavians, specifically in Finland, when making wall logs with saddle notches in the top log, to prevent log stretching, improved the design. They made the edges of the bottom groove (longitudinal notch) narrower and changed the groove shape to a more oval form. As a result, the groove log contacts the bottom log only along the longitudinal groove edges.
Due to its specific nature, buildings with classic bowl-shaped saddle notches usually use wetter logs, and during operation, gaps appear between the logs or joints, making it necessary to additionally caulk, seal, or waterproof with special materials.
The first two described “saddle notches” are commonly called Russian, as they were first developed there.
As mentioned above, both open notches described in the first two points are called – Classic open saddle. However, they can also have an internal cut (wedge).
3. Most log corner joints are saddle notches. Over time, craftsmen experimented, explored new variations, and assigned seemingly different names. Gradually, various saddle notch modifications appeared, featuring internal cutouts, cuts, wedges… Often, both the bottom and top logs are cut for a single joint. However, the advantages and disadvantages of these notches remain the same as those of saddle notches cut in the bottom or top log.
4. The “Saddle Notch” style for corner joints is applied not only to hand-processed round and hewn logs, but also to machine-processed (milled, turned) logs of various shapes.
5. There is a notch where the log ends do not protrude in the corner joints. This notch is called a Trapezoid (Dovetail). This type of corner joint is most often used when the building exterior is further insulated with masonry or when installing a ventilated frame, with boards or planks used for finishing. In earlier times, the external corner of the “dovetail” was simply covered with boards to protect against rain and wind. The advantage of this corner joint is that it is less labor-intensive. Buildings with such notches cannot be tall.
6. Norwegian notch. This is a trapezoid-type notch that self-tightens, so the logs of a drying structure settle under their own weight and fit snugly into the joint. This provides good stability and airtightness. It is the tightest corner joint for buildings constructed using hewn or manually shaped logs (sienojai).
7. Canadian notch. This is essentially the same as the saddle notch with a protrusion, but slightly modified to be self-tightening and self-drying. In proper Lithuanian, it would be called “umbrella-shaped.” It is also referred to as a wedge-type notch.
The Canadian method of corner joining is effective because the log (sienojus) with a prepared longitudinal groove is placed onto the lower log precisely along the edges of the groove. When using wetter logs (20–25% moisture), a larger gap is left at the upper log’s joint, and as the logs dry, they simply “slide/fix” into the lower log. This better prevents wood cracking. Optimal work quality is achieved when a special “compass”/“scraper” with levels is used.
Canadian corner joint also features exterior log protrusions beyond the corner, with groove gaps and without insulating material. To an untrained eye, these gaps might appear as poor workmanship, but that is not true—the gaps of several centimeters allow for wood ventilation and prevent moisture accumulation. They also prevent the log (sienojus) from “hanging,” as drying occurs differently in the protrusions than in the logs within the wall. The Canadian notch is very strong because the corner joint itself secures the logs in place, preventing twisting or shifting.
The Canadian notch is similar to the Norwegian notch and does not require additional insulation.
The Canadian notch can also include an internal wedge.
8. “Blind joint”. This is a log connection where one log does not cut into the other log.
It is considered that the “Saddle” joint with log-end projections is warmer than the trapezoidal/dovetail type connection (joint described in point 5). This is because cold tends to pass along the wood fibers rather than across them. Since the logs have projections, the cold entering through the log ends is slowed at the corner, in the middle of the joint, where thermal insulation is already present, and it is automatically affected by the heat coming from inside the house.
Essentially, each of these corner joint variants has its own production nuances, and by inspecting log buildings, one can discern professional workmanship and spot the shortcuts of less skilled workers. If these details are not noticed at the initial stage, or the client does not know how it should be properly executed, all discrepancies and issues become very apparent later during the building’s operational life. Therefore, hire professionals to avoid regrets in the future.
For each selected style, by applying the wall construction form, the log (sienojus) profile, and the corner joint variant, there are specific exterior design solutions characteristic only to that form. Additionally, by referring to the information provided above, it will be easier to orient yourself when choosing a manufacturer or builder.
