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Logluxe article
Types of timber beams used in house construction
Types of Timber for House Construction: Standard, Dry, Glued, and Insulated Timber
The timber used for construction of a timber houses has many completely different characteristics. Manufacturers offer timber of natural moisture content and chamber drying, solid and glued, models with flat and round surfaces, spikes, Finnish joint and German "comb". What to build a house from? Let's take a closer look at the types of timber.
Classification of glued timber by profile types
The horizontal plane of the part remains flat or is given a special shape for connecting the crowns. Profile section options that are used in most log house projects:
- Flat or with sloped edges. Suitable for the assembly of light structures, smaller in size. Additional inter-crown insulation is required;
- With one or two spikes and grooves. The parts are fixed to each other;
- Finnish type profile. There is space between the spikes for hidden laying of insulation. In some models, it is possible to install an insulating cord in the grooves;
- Comb type (German profile). The horizontal surface is made in the form of teeth that prevent air from passing through. Inter-crown insulation is not required.
German profile. The "comb" is more expensive to manufacture - high production accuracy is required. But if the technology is used, the result is a perfectly warm log house with strong walls that do not need additional insulation.
Sidewall processing
The outer side of the timber is treated in the form of a flat or semicircular surface.
Standard glued-laminated log, with recesses at the top and bottom.
1) In the first case, an almost flat wall is obtained with recesses at the joints of the crowns.
Semicircular log on both sides.
2) In the second case, it resembles a rounded log. The semicircular part is usually left for the outside - it is more convenient to have a flat surface inside.
Timber Types by Moisture Level
Wood moisture level is measured with a specific device.
Natural Moisture Timber:
Kiln-Dried Timber
- This is the cheapest option - the wood is delivered to the construction site immediately after processing. Natural moisture timber can be flat or profiled, but cracks and gaps still appear in it after shrinkage.
- All types of timber houses undergo a shrinkage process, but natural moisture wood deforms more than the rest. The material behaves unpredictably: it bends, twists, cracks, shrinks unevenly, and changes its linear size. The owner will have to seal the gaps and cracks, insulate the walls, and deal with the final finishing no earlier than a year after assembly.
Kiln-Dried Timber
- The material is brought to the required moisture content (usually 8-14%) in special drying chambers, then processed and assembled in a dry state. The shrinkage of such wood is close to the parameters of glued timber, if only the wood does not get wet during construction.
- The main problem with kiln drying timber thicker than 100 mm is cracking. To preserve the surface, it is necessary to increase the time spent in the chamber. The standard treatment for thin wood is 10-12 days. High-quality drying of 150-200 mm timber takes up to several weeks or even months. Attempts to increase the temperature and speed up the process lead to uneven drying - the wet center tears apart the dry outer part.
- Additional drying time and a large amount of defect rejects (some parts crack) make the material more expensive. The wood must be protected from moisture until it is coated (paint or exterior insulation), but the walls deform much less and no repairs are required after shrinkage. If you choose solid timber, kiln drying is much better than natural moisture material. It is from kiln-dried boards that high-quality glued timber is made.
In practice, manufacturers often use "pre-dried" timber, which means that the material spends the prescribed 10 days in the chamber in normal mode. The result is a workpiece with a dry surface and a wet core, which is easy to machine. Such wooden log cabins take on their permanent shape faster, but there is no protection against deformation and cracks.
Wood Types for Timber Production
The choice of wood for timber production significantly impacts the characteristics and overall quality of the final product. Here's an overview of common wood types used for timber:
Proper material combination:
It is possible to use lining boards or make the lower crown from larch. This wood species is less prone to decay, handles moisture well, and protects the rest of the log house from damage.
Improper material combination:
Sometimes manufacturers offer a composite glued timber: the core is made of pine or fir, while the top is made of a more expensive material. Such bonding is unreliable: wood of different species differs in temperature deformations and reacts to changes in humidity.
It is possible to use lining boards or make the lower crown from larch. This wood species is less prone to decay, handles moisture well, and protects the rest of the log house from damage.
Improper material combination:
Sometimes manufacturers offer a composite glued timber: the core is made of pine or fir, while the top is made of a more expensive material. Such bonding is unreliable: wood of different species differs in temperature deformations and reacts to changes in humidity.
Regular, insulated, and glued timber
Regular, double-insulated, and glued timber
The main difference between the materials is the beam structure:
The main difference between the materials is the beam structure:
Regular solid timber in the assembled wall
- Regular solid timber. Produced from a solid log by planing. Minimal processing preserves the natural structure of the wood with all its advantages and disadvantages.
Double-insulated timber with insulation inside
- Double-insulated timber. Consists of three separate parts: two boards (inner and outer) and an insulation layer. The structure resembles a sandwich panel with a wooden base. In some designs, the parts resemble a full-profile timber with insulation in the middle, while in others, a double frame is assembled, into which insulation is placed.
Glulam timber wall with extended log height (2 boards high)
- Glued timber. The part is glued from pre-dried and processed lamellas. With the correct selection of wall thicknesses, strong and warm timber houses are obtained. When the technology is followed, a high-strength part is produced from 5, 7, or more boards.
So, which timber is better to use? Conclusion:
Regular, double-insulated, and glued timber
The main difference between the materials is the beam structure:
The main difference between the materials is the beam structure:
By all signs, it can be seen that quality timber should be:
- Profiled. It is desirable to make the profile in the form of a comb — this way, it is possible to do without insulation and ensure reliable crown grip;
- Glued. Characteristics and properties of glued timber: minimal settling, reduced construction time, and absence of deformations, which gives advantages over regular timber. Compared to double-insulated timber, glued material wins due to wall reliability;
- Sufficient thickness. A difference of 1-2 cm noticeably affects strength, thermal and sound insulation. For sustainable year-round living in the European climate, the optimal option is a wooden wall with a thickness of at least 200 mm.
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