According to the tests that were conducted by an accredited laboratory of the Russian Service for Customer Protection and Wellbeing, Japanese OSHIKA P.I. BOND PI-5340_S2 adhesive has not been classified as hazardous to human health or the environment. The cured product does not contain phenol or formaldehyde, is chemically neutral, and does not emit any odors or toxic compounds.

Glued wooden structures manufactured using this Japanese adhesive comply with all applicable health & safety requirements. This adhesive complies far beyond the environmental standards in the field of residential building materials – even in Japan which has the world's most stringent environmental regulations.

In mid-2020, OSHIKA CORPORATION signed an agreement with Kucherenko Structural Engineering R&D Institute (Russia) and began work on the Russian certification testing of P.I. BOND PI-5340S, PI-5340_S2, and PI-3210_S3 for compliance with functional classes 2b and 3 of Glued Laminated Timber (Glulam), as well as long-term testing of the adhesives for compliance with 1a, 1b and 2a functional classes of Glulam under Russian standard GOST 20850-2014.

Timber for house production undergoes four sorting stages: primary acceptance, screening after drying, sorting after the initial gouging of lamellae (detection of defects), and final sorting prior to gluing of the lamellas. Even when using high-quality rough materials, up to 15% of timber falls short of internal quality standards.

Carefully selecting rough materials, we do not use spliced joints so that the house walls would not look like a chessboard. The elements of 12 meters in length may have 1-3 stud joints visually indistinguishable on the walls covered with glaze finishing compounds.

In LVL manufacturing, we use no.1 and no. 2 (AB) grade spruce in accordance with GOST (State Standard) 8486-86 (Picea abies).

Distribution area: South of the Arkhangelsk region and the North, Northeast of the Vologda region. The timber in these areas has dense annual rings, but not excessively dense as in the Far North regions, where the material becomes spalt.

Why do we use exclusively spruce for the production of houses?

As a house construction material, spruce has a number of indisputable advantages:

• In terms of heat conductivity, spruce houses are the warmest next to cedar;
• Spruce wood is much lighter than pine and larch (workability and lower foundation load);
• Spruce has no duramen, so the wood has level white shade not darkening with time, which makes the glue joint indistinguishable;
• The knots ate light, small and of regular shape, which does not spoil the aesthetics of the walls;
• Spruce branches are light, small, and of right shape, so the aesthetic look of the walls is not spoiled;
• Spruce has small regular-shaped resin pockets and produce less resin than pine;
• Spruce wood is straightgrained, less exposed to deformation and is bonded more firmly due to its moisture-resistant structure. Minor fine checks that appear on the walls surface in the process of house maintenance do not affect the aesthetic perception.
• Spruce has higher load-carrying capacity than pine, for instance. Spruce is less dense, but more flexible material. The ultimate tensile strength of spruce relative to pine is 1223/1150 kgf/m2. Therefore, load-bearing structural elements made of spruce are more solid than of pine.

The lower heat conductivity, the better the heat-trapping ability of the material.

The key reasons for protective treatment of wood are the following:

1. Protection from adverse environmental factors at construction stages (temperature extremes, excessive moisture, uneven wood shrinkage, solar UV radiation, exposure of joining elements to rainfall, unfinished open construction) preceding walls finishing with paints and varnishes.
2. Maximally extended maintenance overhaul period of house elements.
3. Additional protective properties of structural elements: low flammability and fire resistance.

It is worth mentioning that, contrary to log houses, the replacement of parts of glued timber houses is a serious challenge due to perfectly fine factory connections, mortise and tenon cutout (“coating fitness gauge”).

Protective treatment of wood and the use of sealing compounds for abutting ends against cracking allows for even loss of moisture, which significantly reduces the probability of large cracks.

Colour matching of protective compositions allows for tinting the surface of laminated logs and provides additional protection against solar UV radiation, which makes the extensive polishing of UV-damaged rough material prior to laying of the finishing coat unnecessary.

Fire protection of wooden structures mitigates ignition risks and increases the burning time/smoldering period of the building, which makes it possible to evacuate people and valuables from a residential building in sufficient time.

Protective treatment of laminated logs on construction site afield has a number of significant setbacks:

1. Spraying, coating or brushing techniques are applicable only at positive temperatures during the warm season;
2. The precision of works and productivity depends on the motivation of the builders (defects, drips, insufficient penetration depth of the composition);
3. The preservative treatment of the assembled walls does not allow for protecting LVL cross sections and joining elements;
4. Сheaper protective compositions can be washed off the LVL surface;
5. Underconcentrated (water-diluted) composition.

Advantages of in-house protective treatment in the factory:

1. Automatic application of composition using “Scorpion 20” machine-tool, which provides sufficient penetration depth and even application due to nylon rollers and brushes that allow for even and simultaneous penetration of the composition into the material from 4 sides.
2. Action speed of the flow-line method that makes it possible to save considerable time during the assembling of the building.
3. The material is processed in shop-floor conditions that allows for retaining the origine quality of the processed surface.
4. Non-existence of stains on the surface of elements.
5. The machine-tool filters the wood waste and reutilizes defluent preservative which makes it possible to economize the material.
6. Extended storage period of the preservative-treated and packaged kit house under unfavourable environmental conditions, in particular when transporting it to tropical countries in containers by sea.