Liquid cork or cork sealant: characteristics and prices

Recommendation points

• Composition and properties of the sealant
• Manufacturer’s choice
• Use in thermal protection systems
• Sealing of building structures
• Floor finishing
• Sealing assembly seams
• Application in sound insulation systems

Relatively recently, a new type of plastic fillers has appeared on the building materials market – cork sealants, or liquid cork. It is to them that our today’s educational program is dedicated, which will acquaint readers with the properties of this material, the features of choice, as well as the scope.

Composition and properties of the sealant

The practical characteristics of cork sealants are determined by its main filler – cork chips, the share of which can be up to 90%. Another 5-7% of the volume is occupied by polymer binders, the rest is water, which is necessary to give the composition the desired consistency.

The qualities of the raw materials used as fillers determine the behavior of the sealant during operation. The cork has firmness and elasticity, these properties are preserved after the composition hardens. Other most pronounced features are low thermal conductivity, low specific gravity, environmental friendliness and resistance to organic damage.

The behavior of the composition during application and the scope of its application depend on the properties of the polymer binder. Most manufacturers use polyacrylate-based glue as a bonding agent for cork granules. It is a water-soluble composition that does not contain and does not release volatile substances when solidified. Polyacrylates have excellent adhesion to most building materials, and their physical properties are very similar to cork chips. At the same time, the binder eliminates such disadvantages of the cork as hygroscopicity and the ability to decompose under the influence of oxidants and ultraviolet radiation..

Manufacturer’s choice

On the market of Russia and the CIS countries, cork sealant, or liquid cork, are represented by several brands. ISOCORK and Bostik have the largest sales area, and there are also lesser known manufacturers. The cost ranges from 250-300 rubles per 500 ml when packed in a plastic tube and can reach 500 rubles when delivered in syringe tubes. The choice of cork sealant on the market is significantly lower than that of conventional liquid cork. These compositions should not be confused: stabilizers and modifiers are added to the cork plaster, which increase the operational properties, but such substances reduce the environmental friendliness of the material..

It should be noted that the technology for the production of cork sealant is simple and therefore products of different brands do not have any significant differences. The choice should be made based on the cost of the material and the volume of packaging, taking into account the recommendations of the contractors and the developer of the construction project.

There is also one caveat. Polyacrylates and compositions based on them are capable of losing their properties over time, therefore, the less the sealant has been in the warehouse, the better. It is worth asking the seller which manufacturer from his assortment is in the greatest demand: this sealant is imported more often, which means there is less chance of purchasing an illiquid product.

Use in thermal protection systems

If cork agglomerate is used as insulation, there are several important requirements for the installation process. Seam sealing is a mandatory step. In hidden systems of insulation, it is necessary to eliminate blowing and cold bridges while ensuring maximum layer uniformity. If the cork material is used as a topcoat or under wallpapering, it is necessary to eliminate irregularities at the joints and hide them visually.

Cork sealant copes with all these tasks perfectly. It is quite sticky and, when attached to the cut of the cork board, forms an almost monolithic structure. The plasticity of the composition allows you to fill the entire cavity of the joint and carefully smooth the surface. Most series of such sealants are available with an extended color card and can be easily tinted with dispersed tinting concentrates..

The installation process consists in applying or introducing a small amount of sealant into the joint, pressing it in and smoothing it with an elastic spatula. When working with roll materials, it is convenient to use a sealant packed in a polyethylene tube: the composition is squeezed out of it in small portions onto a palette, where it is given the desired color and shade, then the composition is pressed into the joint with light movements of a spatula. To seal joints in black agglomerate, it is convenient to use sealants in syringe tubes: a thin nozzle allows you to fill the seam from the root itself, and with due diligence – without excess that needs to be removed or smoothed.

Sealing of building structures

Prefabricated structures made of self-supporting insulated wire or reinforced concrete panels have low stability and are prone to seasonal linear fluctuations. It is rather difficult to ensure the tightness of such buildings: most aggregates in such conditions quickly lose their qualities. So, the most commonly used polyurethane foam for this purpose becomes brittle over time and crumbles into gunpowder. Hard sealants, in turn, do not have sufficient elasticity and form cracks. The only suitable material for such purposes is non-drying viscous mastics, but they do not quite fit into the environmental construction standards, and they are expensive..

Cork sealant is well suited as a filler for joints, including for joints. With its help, it is possible to achieve a very high-quality sealing of the edges of the sandwich panels and the elimination of cold bridges at the junctions to the frame. Inhabitants of apartments in panel houses can also be very useful in the next renovation to cut the joints between the panels and the ceiling and fill them with cork sealant, which will eliminate air noise, drafts and block the path of insects from neighboring apartments.

However, cork sealant is not very well suited for caulking a log house using the “warm seam” technology. With a minimum amount of risk, you can use it for established houses from profiled timber with high-quality dowel fastening. However, in log cabins, twists and linear displacements are too large, while the cork sealant does not show sufficient elasticity and adhesion to wet wood..

Floor finishing

When laying linoleum, open joints are very popular: the absence of a threshold has a beneficial effect on both appearance and safety. Cold sealing with cork sealant can be used to fill a pattern-oriented joint. This is especially beneficial for thick linoleum where the cork filler can be the base of the joint for use with a thinner welding cord. The most important requirement for such an application is thorough cleaning of the joint with a vacuum cleaner and degreasing it with alcohol..

Using the same technology, it is possible to perform a very technological sealing of the adjoining tile to the laminate or linoleum. If the level of the finished floor is initially adjusted to a uniform surface, this method demonstrates high aesthetics and durability. The ductility of the joint is high enough to compensate for both shrinkage and thermal deformation of the laminate, and vibrations from through loads. The best result is achieved provided that a groove is made in the glue joint under the edge of the tile, then the composition forms a reverse wedge that cannot be squeezed out.

When laying floor coverings, cork sealant is well suited for sealing floor-to-wall joints. Such a seal does not interfere with linear vibrations of the floor, while small insects are blocked. The benefits of sealing a floor insulated with mineral wool are especially great: when the floor vibrates, there is no air flow that takes out small stone fibers from the cavity.

Sealing assembly seams

The ability of fella (plug) to prevent the propagation of mechanical vibrations is well known. This property is widely used in noise protection systems, and here cork sealant is once again used. The most famous example is the device of expansion gaps between partitions and capital structures. Filling them with a liquid plug almost completely eliminates airborne noise and well prevents the proliferation of structural.

In addition, due to the elastic properties of the cork filler, the impact on the partition from building structures is reduced. When installing frames under the gypsum board, the sealant is applied to the middle shelf of the guide profiles, prepared for installation. This allows you to more accurately adjust the clamping position and compensate for gaps of varying thickness. The seams of the abutment of partitions made of aerated concrete or gypsum blocks are filled after the masonry has shrunk from a syringe tube, and the composition does not have to be applied to the full depth of the seam.

Application in sound insulation systems

The properties of cork granulate make it possible to use sealants based on it for joining and gluing sound-absorbing panels. The latter is also facilitated by the high adhesion of the acrylic binder to a wide range of materials..

The high density of the cork sealant does not completely eliminate construction noise, however, it will not be superfluous to use the cork when laying subfloor or floor boards. A small porous layer will prevent squeaking between floorboards and joists, and will also act as an impact noise damper.

Cork sealants are also used in automotive sound insulation. The purpose is the same: sealing the joints and fixing the main blocks of the sound-absorbing filler. The use of cork filler for vibration damping is widespread: in the supports of table-top machines, small vibration tables, when installing portable power generators. Cork sealant can also be used to make parts by injection molding, which expands the range of possibilities for the DIY DIYer..