Which adhesive is used for the lamellar structures of wooden houses

Prefabricated frame houses, those that are largely factory-built, have the walls built on a timber frame. Each wall consists of a frame of vertical posts and horizontal beams, stiffened with OSB or other structural panels. In order to be very stable and strong, the frames are made of laminated elements, i.e. structures obtained by overlapping and gluing several layers of wood, a process similar to that used to obtain massive panels. For a secure and strong bond, D4 wood adhesives are used, i.e. an adhesive that is highly resistant to moisture and outdoor conditions. Consistent quality glue is the key to durable houses, which is why long-lasting partnerships between the house and glue manufacturer are built on long-lasting partnerships. This is demonstrated by the partnership of over 10 years between Szolvegy - manufacturer of adhesives and Dimmer, one of the best-known manufacturers of prefabricated houses.

What are laminates and how are they made

They are called laminate because the overlapping of all the wood elements is parallel to the grain, not perpendicular, as in tackle. Their purpose is to eliminate defects and stabilize the wood. Compared to a post or beam made from a single piece of wood, there is no risk of cracking, warping or dimensional variation in laminated beams.

After the lumber has been cut and dried in the dry kilns, each piece is analyzed to identify knots, cracked or loose knots and other possible defects, which are then removed. The remaining pieces of wood are too small in size to be used to make poles, so they are milled at the ends to be finger-jointed. Teething allows long elements with very good strength. The resulting teeth increase the contact surface area between the two elements and transform a bond of fiber ends into a bond of parallel fibers, which is much stronger.

Adhesive is applied to the side edge of each such extended element, and then several similar elements are placed in the press, edge on edge, forming a panel of elements glued to the sides. The adhesive is applied in excess so that, by pressing, the excess comes out. This is a way of checking that there is adhesive all over the surface. After the time needed for the adhesive to react, the panel is removed from the press, sanded and calibrated to remove the hardened adhesive on the outside and cut to obtain the beams and posts.

Qualities of the adhesive used to produce laminates

The adhesive used for both the finger-joint and the panel joint must be very strong. This is why D4 wood adhesives are used, which are the best adhesives in terms of moisture resistance and outdoor conditions. Dimmer uses TISZAPUR D4, a polyurethane adhesive.

Polyurethane adhesives are the most durable and strongest adhesives for wood. They are versatile and can bond wood, glass, metal, ceramics, polyurethane foam, textiles, plastic or stone in addition to wood. They resist moisture very well and are very suitable for use both indoors in high humidity and outdoors. They can equally well bond solid wood or wood derivatives.

The TISZAPUR D4 adhesive used by Dimmer for the production of laminate elements is one-component. The film-forming reaction takes place with the help of atmospheric and wood moisture. It is simpler to use than conventional two-component polyurethane adhesives (adhesive and hardener), provided that it is protected from moisture when not in use, i.e. the packaging is hermetically sealed. The resulting adhesive film adheres very well to the surface of the wood, is very elastic, resistant to water and mechanical action and very durable.

To ensure that it was the best option for obtaining structures for houses, Szolvegy tested the gluing under conditions tougher than those recommended in the product data sheet. They made beams that were tested in autoclaves at high temperatures and then left outside for a long time in both winter and summer conditions. The beams withstood all these tests very well.

A partnership based on the quality of the product supplied and compliance with recommended technology

The tests to which the adhesives have been subjected, the permanent and random quality control of the manufactured adhesives are the reason why, in more than 10 years of collaboration, there have been no quality problems. I would like to mention, however, that no matter how good an adhesive may be, if it is not well and correctly applied, if the setting or rest times are not respected, if it is not correctly stored and if the shelf life is not respected, the results will not be as expected. There needs to be collaboration between the two parties to avoid mishaps. The adhesive, without correct application, loses its qualities, however good it is.

Dimmer has been producing wooden houses for many years and many of them have been made in European countries. Romanians have been more reluctant to this type of construction, mainly due to lack of information in the field. Fortunately, we have been building them for a few years now and the number of people who choose to build their homes in this way is growing all the time. This is also because more and more information about energy efficiency prefabricated wall houses, short working time and lack of on-site waste.

And one of the reasons for their strength and durability is also the use of adhesives with good bonding properties, resistant over time and in extreme conditions and consistent in quality.