EP3784455A1

EP3784455A1 - Physical decoupling of above- and below-ground wood moisture of wooden components in earth or water contact

Info

Publication number: EP3784455A1
Application number: EP19719838.5A
Authority: EP
Inventors: Michael Pallaske; Marco FLECKENSTEIN; Sascha HELLKAMP; Peter JÜNGEL
Original assignee: Kurt Obermeier & Co Kg GmbH
Current assignee: KURT OBERMEIER GMBH
Priority date: 2018-04-24
Filing date: 2019-04-24
Publication date: 2021-03-03
Also published as: WO2019206930A1; DE102018003341A1

Abstract

The invention relates to a method for the physical decoupling of above- and below-ground wood moisture of wooden components in earth or water contact, a barrier means for physically decoupling above- and below-ground wood moisture and a device for permanently ensuring increased wood moisture in the wooden component below the barrier layer, wherein, according to the method, a water vapor- and/or water-impermeable barrier zone is formed over the entire component cross-section in the region of the earth/air zone or the water/air zone, which separates the water balance of the air-contacting component section from that of the component section with moisture contact, and wherein the device for permanently ensuring increased wood moisture in the wooden component below the barrier layer is designed in such a way that a below-ground component surface is surrounded by a gas- and water-impermeable layer, wherein said layer begins in the region of the barrier layer and ends just in front of the underside of the below-ground component region.

Description

Physical decoupling of surface and underground wood moisture from

Wooden components in earth or water contact

In the case of all timber components that are grounded in the ground (masts, palisades, support piles, etc.), the soil contact in the area below the soil surface ensures a continuous increase in wood moisture content above 80%, which largely suppresses attack by wood-destroying basidiomycetes in the soil area. In the above-ground area of the wood component, however, the wood moisture is about 20%, so it is too low to be attacked by wood-destroying fungi.

The same conditions occur with woods that are installed in the water; Here the wood below the water surface is too humid for a fungal attack and above too dry. In the following, only the considerations of wooden components in the earth contact are carried out, they are essentially also for wood, which are installed in the water and their transition area between the water surface and air.

Timber components, which are established in the soil, are usually impregnated with a chemical wood preservative and in this way the service life is considerably extended. This protective measure is supported in the earth by the permanently high wood moisture and above the soil by the low moisture content and rapid drying after rain events. A particularly critical area is the transition zone (earth / air zone) in which all wood moisture occurs and is

For most wood-destroying mushrooms an area for optimal growth finds. Since the chemical protection treatment is limited only to the impregnable areas of the sapwood, wood-destroying fungi can migrate through dry cracks that extend through the protected area into the unprotected heartwood and cause massive internal or nuclear fouling there.

These rotting damages developing from the inside are particularly critical, since they are not recognizable for a long time and on the other hand the wooden component is increasingly weakened at the level of the ground level, ie where the greatest compressive and tensile forces occur under wind load. Here, the fracture mechanism of the weakened wood differs considerably from that of an undamaged wood component. In weakened wood, the break occurs suddenly and without any warning, while the break in intact wood usually announces a splintering of the fiber structure.

The location of this transition zone in the area of the ground / air boundary is dynamic; it depends on the seasonal differences in the amount of precipitation, which essentially influence the water content in the soil and thus the moisture supply to the underground area of the timber component. In dry periods, near-surface soil areas may cause premature capillary moisture removal from the wood into the dry soil, and the transition area shifts below the soil surface. In rainy periods, the high soil moisture, supported by the moistening of the above-ground area, shifts the transition area over the soil surface. This dynamic is also reflected in the harmful images of the inner rot; they sometimes extend over more than one meter inside the component and can expand up to one meter below the ground / air limit - in dry locations.

The present invention is the prevention of wood moisture gradient in the transition region between the sub-surface and above-ground area of wood components, which are founded in the ground, or in the transition region above the water surface in wooden components, which are installed in water. This object is achieved in that in the transition region a comprehensive wood cross-section barrier which prevents the capillary water transport in the wood and the diffusion in the wood. By this measure, a hydraulic decoupling of the air-contacted and the moisture-contaminated area is achieved in the timber member and prevents the formation of a wood moisture gradient in the transition zone.

Likewise provided by the present invention is a sheath which complements the barrier layer of the subterranean area with an oxygen- and / or water-impermeable material (sleeve), so that in dry periods no premature, capillary moisture removal and no diffusion of water from the wood into the near-surface, dry floor areas can take place. This casing begins above the ground in the region of the barrier layer according to the invention and encloses the underground area of the timber component completely or only in parts. The soil-contacting side of the brain, however, remains open in any case, so that the soil moisture here has unhindered access and the desired high wood moisture is ensured in the subterranean component area. In addition to moisture loss from the subterranean component area, a gastight version of the sleeve material also prevents the ingress of oxygen into the damp wood. By this measure, the oxygen supply is minimized in the wet component area and the activity of the ubiquitous microorganisms then leads relatively quickly to anaerobic conditions. Such anaerobic conditions additionally protect the wood, since under these conditions wood-destroying Basidiomycetes can not grow at all and mildew rotors can only grow to a limited extent or greatly delayed.

The cuff technology itself is well known and is used with noticeable success in many variants to support the chemical wood preservation measures in the area of the mast base and / or in the area of the earth / air zone.

EP 2 019 891 B1 describes a sleeve made of a metal foil which surrounds the underground base of the mast and is fixed on it via an overlying shrinking tube. The effect of the metal foil is described as "oligodynamic" and thus utilizes the biocidal properties of metal ions released from the foil. EP 2 574 435 A2 describes an almost identical sleeve system, only the effect of the metal foil is no longer described as "oligodynamic" but as "oxygen-consuming".

In the PCT application WO 03/038213 A1 a sleeve system is described, which may consist of several layers, which are composed of different materials with different functions (Termitenschutz, reduction of drug losses in the soil, etc.).

All cuff systems are aimed either at a complementary chemical protective effect and / or at a physical reduction of the infestation pressure by wood-destroying organisms in the area of the earth / air zone.

None of the sleeve systems described so far is able to prevent the formation of the wood moisture gradient. This critical area is only moved from the transition zone earth / air zone to the aboveground cuff end. As a result of this shift in the wood moisture gradient, the infestation pressure is only reduced by microorganisms of any kind which are highest in the area near the ground. However, the critical wood moisture gradient remains at the upper end of the cuff and still provides optimal conditions for infestation by wood-destroying fungi (approach of spores, etc.).

Fig. 1 shows a wooden component (mast) with a central bore in the heartwood for

Inclusion of the injection packer.

Fig. 2 shows a wooden component (support pile) with a circumferential, open towards the wood, self-sealing sleeve for the compression of the agent from the outside.

Fig. 3 shows a wood component (mast) with four holes which are perpendicular to the longitudinal axis by the distance V _t from the center line of the timber member and the distance V _h horizontally offset from each other to the core.

Fig. 4 shows a wood component (mast) with a bore which is offset at an angle W _v to the longitudinal axis and by the distance V _t from the center line of the wood component to the core was led. In general, several of these holes on opposite sides and by the distance V _h horizontally offset from each other (see Example 3) attached.

Fig. 5 shows a wooden component (mast) with a bore which is at an angle W _h obliquely to the longitudinal axis and by the distance V _t offset from the center line of the wood component was guided into the core. In general, several of these holes on opposite sides and by the distance V _h horizontally offset from each other (see Example 3) attached.

The inventive decoupling of the above and below ground water balance by a water and water vapor impermeable barrier layer prevents the occurrence of optimal growth conditions. To ensure that in the underground area of the wood components, the moisture content does not drop below the maximum existence of wood-destroying fungi during seasonal periods of drought, the use of the cuff technology according to the invention as supportive measure also lends itself to several reasons. By means of a suitably attached, water-impermeable sleeve material, the water absorbed on the underground side of the brain is kept in the area below the barrier layer during seasonal drying periods and ensures permanently high levels of wood moisture. If the sleeve material is additionally gas-tight, then the greatly reduced oxygen supply in conjunction with the activity of the ubiquitously present microorganisms leads relatively quickly to anaerobic conditions; It is therefore possible to completely dispense with oxygen-consuming, chemical measures.

According to the invention, according to the invention, a barrier layer comprising the entire cross-section of the wood is set up in the form of the wood, some very specific requirements are set:

- As complete as possible saturation of the wood cell walls

- Closure of the large-pored water pipe elements (tracheids and tracheids) or at least the dots between these elements

- minimal changes in wood elasticity

- the lowest possible impact on the fracture behavior - permanent connection with the inner surfaces of the wood cells

- Durable water resistance of the barrier material

no change in elastic properties (e.g., embrittlement or cracking)

permanent resistance of the barrier material to biotic factors.

In the following some, likewise inventive, design options of such a blocking agent are exemplified:

A.) blocking agents based on fats and / or oils and / or waxes, preferably based on waxes and particularly preferably based on paraffins. The viscosity of these starting materials can be adjusted prior to introduction into the wood by heating so that a distribution in the heartwood is possible. If necessary, the area of the barrier layer can be preheated prior to treatment by means of heating mats, infrared radiators or microwave ovens to ensure a homogeneous distribution of the medium.

B.) blocking agents based on mixtures of different silane monomers and / or

Silane oligomers and / or siloxane monomers and / or siloxane oligomers, which is introduced as a low-viscosity preliminary solution in the wood and then brought to polymerization. Silane chemistry offers a variety of opportunities for producing well-adhering, highly flexible and durable polymers that can be cross-linked in one or more ways as single-component or two-component systems at room temperature.

C.) blocking agents based on oligomeric epoxy resins, preferably based on aliphatic epoxy resins, particularly preferably based on preferably linearly crosslinking aliphatic glycidyl epoxy resins of low molar mass, which are introduced as a low-viscosity mixture in the wood and then brought to polymerization.

D.) blocking agents based on low-viscosity polyurethane oligomers and / or their monomers (diols and diisocyanates), which are introduced as a low-viscosity mixture in the wood and then brought to polymerization. By adding small amounts of water in the polymerization C0 ₂ and thus an additional pressure, which additionally supports the penetration of the agent.

E.) blocking agent based on furfuryl alcohol and suitable catalysts in an organic solvent, which is introduced into the wood and then polymerized there.

F.) blocking agents based on monomeric or oligomeric acrylates, which are introduced together with a radical initiator into the wood and then brought there to polymerize. Or acrylate dispersions (aqueous or solvent-based systems) that are incorporated into the wood and then physically harden.

G.) blocking agents based on a mixture of different phenol-formaldehyde

Precondensates preferably selected from mono-, di-, tri-, tetrafunctional phenols and crosslinking chemicals selected from formaldehyde, acetaldehyde, glyoxal and other suitable crosslinkers. The phenol-formaldehyde precondensates are introduced into the wood as a low-viscosity preliminary solution and then brought to polymerization. Phenol-formaldehyde resins permanently form stable polymers that can be crosslinked at room temperature to high temperatures in a variety of ways.

H.) blocking agents based on a mixture of different melamine

Formaldehyde precondensates preferably selected from mono-, di-, tri- and tetrafunctional melamines and crosslinking chemicals selected from formaldehyde, acetaldehyde and glyoxal and other suitable crosslinkers. The melamine-formaldehyde precondensates are introduced into the wood as a low-viscosity preliminary solution and then brought to polymerization. Melamine-formaldehyde resins form permanently stable polymers that can be crosslinked at room temperatures to high temperatures in a variety of ways.

I.) blocking agents based on a mixture of different DMDHEUs (1, 3)

Dimethylol-4,5-dihydroxyethyleneurea) precondensates and crosslinking chemicals selected from formaldehyde, acetaldehyde and glyoxal and other suitable crosslinkers. The DMDHEU precondensates are introduced into the wood as a low-viscosity preliminary solution and then brought to polymerization. DMDHEU resins form permanent polymers that are used in Room temperature can be brought to high temperatures in various ways for networking.

J.) Combinations in different percentages of the blocking agents listed in points A. - I.

The construction of the barrier layer according to the invention in the timber component can be done in several ways:

1.) In the heartwood, one or more bores are applied in the axial direction to the desired position of the barrier layer (see FIG. 1). In each hole an injection packer is hammered to the end of the borehole. Subsequently, the pressing of the agent takes place until it has been distributed at the position of the packer from the inside through the entire wood cross section. After completion of the polymerization, the barrier layer according to the invention is formed in this region. This method is only applicable to wooden components that are not yet in the ground.

2.) At the desired position of the barrier layer, a circumferential, self-sealing sleeve is attached, which is open to the wood surface (see Fig. 2). Subsequently, the agent is pressed under pressure into the cuff and the agent is distributed from the outside through the entire wood cross-section. This method is preferably applicable to round wooden components with a small diameter and can also be applied to components that are already in the ground.

3.) There are several holes perpendicular to the longitudinal axis and the distance

V _t (see Fig. 3) offset from the center line of the timber component to the core. In order to affect the statics of the wood body as little as possible, the holes can also be mounted horizontally offset by the distance V _h . Each hole is closed with an injection packer. Subsequently, the pressing of the agent is carried out until it has been distributed around the hole from the inside in a part of the wood cross-section. The compressed partial cross sections then overlap in the wood to one contiguous barrier layer. After completion of the polymerization of the agent, the barrier layer according to the invention is formed in this region. This method is applicable to wooden components that are not yet in the ground, but it can also be carried out as a post-mortem on already installed wooden components on site. There are several holes at an angle W _v to the longitudinal axis and around the

Distance V _t (see Fig. 4) offset from the center line of the timber component to the core. In order to affect the statics of the wood body as little as possible, the holes can also be horizontally offset by the distance V _h (see Fig. 3) are mounted. Each hole is closed with an injection packer. Subsequently, the pressing of the agent is carried out until it has been distributed around the hole from the inside in a part of the wood cross-section. The compressed partial cross-sections then overlap in the wood to form a coherent barrier layer. After completion of the polymerization of the agent, the barrier layer according to the invention is formed in this region. This method is applicable to wooden components that are not yet in the ground, but it can also be carried out as a post-mortem on already installed wooden components on site. There are several holes at an angle W _v to the longitudinal axis, at an angle W _h obliquely to the longitudinal axis and by the distance V _t (see Fig. 5) offset from the center line of the timber member to the core. In order to minimize the impact on the statics of the wood body, the bores can be additionally offset horizontally by the distance V _h (see example 3). Each hole is closed with an injection packer. Subsequently, the pressing of the agent is carried out until it has been distributed around the hole from the inside in a part of the wood cross-section. The compressed partial cross-sections then overlap in the wood to form a coherent barrier layer. After completion of the polymerization of the agent, the barrier layer according to the invention is formed in this region. This method is applicable to wooden components that are not yet in the ground, but it can also be carried out as a post-mortem on already installed wooden components on site. Which of the above exemplified drilling schemes is used depends on the type of wood, the core portion, the sapwood width and the wood moisture on site. The same applies to the diameter and depth of the holes, as well as their number and horizontal offset. The selection and the material of the grouting packer depend on the formulation of the grout to be grouted.

To ensure that below the barrier a sufficiently high moisture content against fungal infection is maintained even during seasonal periods of drought, starting at the level of the barrier layer, a complementary sheath of the subterranean component area with a gas and / or water impermeable material (sleeve) carried out become. This sleeve serves exclusively to prevent water losses in gaseous (diffusion) and / or liquid form (capillarity) from the subterranean component area into the surrounding earth. The cuff can, in conjunction with the barrier layer according to the invention, be attached as a supplementary measure for aftercare on already standing in the ground wooden components. However, it should preferably already, in conjunction with the barrier layer of the invention, be installed as a complementary measure before installation of the component in the ground, begin above the ground in the barrier layer according to the invention and enclose the subterranean area of the timber component completely or in large parts. However, the soil-contacting side of the brain and a small area above it remain without any cover, so that the soil moisture here has unhindered access and thus ensures the desired high wood moisture in the subterranean component area.

Below are some preferred embodiments of the supplementary

Cuffs described:

M1.) Cuff of a water-resistant self-adhesive metal foil, wherein preferably a butyl rubber compound as an adhesive and as a metal aluminum or an aluminum alloy are used. This film is stretchable, impermeable to water, water vapor and gases and can be processed very well and uncritically in practice. The adhesive layer prevents direct contact between the protective-treated wood and the aluminum, so that no aluminum corrosion by Schutzmittelbestandteile can be done. For this reason, should not be waived when attaching this film on the adhesive layer.

M2.) Cuff made of a water-resistant self-adhesive plastic, wherein preferably a butyl rubber compound as an adhesive and a durable weather-resistant, metal-damped plastic and / or a durable weather-resistant, metallized plastic composite material are used. These materials, which have been made into barrier plastics by metal vapor deposition, are elastic, impermeable to water, largely impermeable to water vapor and gases, and can be processed very well and uncritically in practice. When compatibility of the film material with the protective treated wood can be dispensed with in the attachment of this film on the adhesive layer and resort to other fixation methods.

M3.) Cuff made of a waterproof self-adhesive plastic, wherein preferably a butyl rubber compound as an adhesive and as a plastic preferably polyethylene naphthenate (PEN) and / or polyethylene terephthalate (PET) or polyvinylidene chloride (PVDC) are used. These

Barrier plastics are elastic, impermeable to water, largely impermeable to water vapor and gases, and can be processed very well and uncritically in practice. If the film material is compatible with the protective-treated wood, it is possible to dispense with the adhesive layer when fixing this film and to resort to other methods of fixing.

M4.) Cuff made of a waterproof self-adhesive plastic, wherein preferably a butyl rubber compound as an adhesive and a durable weather-resistant plastic and / or a durable weather-resistant plastic composite material are used. Such cuffs are more or less extensible, impermeable to water, but may be partially permeable to water vapor and gases, especially oxygen. Due to this partial permeability, the functionality of the cuff is at least partially impaired. When compatibility of the film material with the protective treated wood can be dispensed with in the attachment of this film on the adhesive layer and resort to other fixation methods. M5.) Manschete from a weather-resistant silicone rubber, preferably an RTV silicone rubber and more preferably a RTV-1 silicone rubber, with which the sleeve provided for the component area is coated and then polymerized to a water-impermeable elastic layer. Such cuddles are very elastic and impermeable to water, but an impermeability to water vapor and gases must be brought about additives (eg iron mica and / or aluminum flakes).

The subsequent attachment of the aforementioned types of custody as part of Nachpflegemaßnahmen is preferably carried out after the establishment of the barrier layer according to the invention in the region of the earth / air zone. The soil-contacting component area is exposed to a depth of 30 cm to about 50 cm and cleaned; then the cufflinks are fastened to the underground wooden surface and if necessary guided to the air-contacting component area to about 10 cm beyond the barrier layer. Subsequently, the excavated soil is filled back into the hole around the component and compacted. If additional treatment of the soil / air zone with biocides is required, then it should be done below the barrier and before attaching the cuffs.

The preventive attachment of the aforementioned types of clover to supplement the chemical wood protection is also preferably after the establishment of the barrier layer according to the invention in the later region of the earth / air zone. About 70% to 95% of the underground wood surface is covered homogeneously by the clover, whereby the bottom side of the cerebrum and part of the overlying wooden surface must remain accessible for direct earth contact. Here, deep in the soil in the future, the water absorption into the wooden component takes place at the lowest point and produces the desired high wood moisture in the subterranean component area up to the barrier layer. The cuff will continue in the future aboveground component area ends up to about 10 cm above the barrier layer.

Claims

Kurt Obermeier GmbH & Co. KG 22515 II Claims:

1. A method for the physical decoupling of the above-ground and underground wood moisture of wood components in earth or water contact, characterized in that in the earth / air zone or the water / air zone a water vapor and / or water impermeable, the entire component cross-section detecting Exclusion zone is built, which separates the water balance of the air-contacting component portion of the component part with moisture contact.

2. The method according to claim 1, characterized in that the means for establishing the exclusion zone of suitable fats and / or oils and / or waxes, preferably waxes and particularly preferably consists of paraffins, wherein the viscosity of these starting materials prior to introduction into the wood Heating is adjusted so that also takes place in the distribution of heartwood.

3. The method according to claim 1, characterized in that the means for establishing the exclusion zone consists of a mixture of different silane monomers and / or silane oligomers and / or siloxane monomers and / or siloxane oligomers, which as a low-viscosity preliminary solution in the Wood introduced and there is brought to polymerization.

4. The method according to claim 1, characterized in that the means for establishing the exclusion zone of oligomeric epoxy resins, preferably based on aliphatic epoxy resins, more preferably based on preferably linearly crosslinking aliphatic glycidyl epoxy resins low molar mass, which is a low-viscosity mixture in the wood is introduced and brought there for polymerization.

5. The method according to claim 1, characterized in that the means for establishing the exclusion zone consists of low-viscosity polyurethane oligomers and / or their monomers (diols and diisocyanates), which are introduced as a low-viscosity mixture in the wood and polymerize there.

6. The method according to claim 1, characterized in that the means for establishing the exclusion zone consists of a mixture of furfuryl alcohol, suitable catalysts and organic solvents is introduced into the wood and then polymerized there.

7. The method according to claim 1, characterized in that the means for establishing the exclusion zone of a mixture of monomeric or oligomeric acrylates, which are either dissolved or introduced as an aqueous dispersion in the wood and then brought there to polymerize.

8. blocking agent based on a mixture of various phenol-formaldehyde precondensates preferably selected from mono-, di-, tri-, tetrafunctional phenols and crosslinking chemicals preferably selected from formaldehyde, acetaldehyde and glyoxal, wherein the phenol-formaldehyde precondensates as a low-viscosity preliminary solution in the wood is introduced and then brought to polymerization.

9. blocking agent based on a mixture of different melamine-formaldehyde precondensates preferably selected from mono-, di-, tri- and tetrafunctional melamines and crosslinking chemicals preferably selected from formaldehyde, acetaldehyde and glyoxal, wherein the melamine-formaldehyde precondensates as a low-viscosity preliminary solution in the wood is introduced and then brought to polymerization.

10. blocking agent based on a mixture of different DMDHEUs (1, 3)

Dimethylol-4,5-dihydroxyethyleneurea) precondensates and

Crosslinking chemicals preferably selected from formaldehyde, acetaldehyde and glyoxal, wherein the DMDHEU precondensates are introduced as a low-viscosity preliminary solution in the wood and then brought to the polymerization.

11. A device for permanently securing increased wood moisture in the timber component below the barrier layer according to one of claims 2 to 10, characterized in that the subterranean component surface is surrounded by a gas- and water-impermeable layer, said layer begins in the region of the barrier layer and shortly before Bottom of the subterranean component area ends so that at least the bottom side end grain surface is in direct contact with the soil and can absorb water.

12. A device for permanently ensuring increased wood moisture in the timber component below the barrier layer according to one of claims 2 to 10, characterized in that the subterranean component surface is surrounded by a water-impermeable layer, which also severely limits the diffusion of water vapor; wherein this layer begins in the region of the barrier layer and ends just before the underside of the subterranean component region, so that at least the bottom side end grain surface is in direct contact with the soil and can absorb water.

13. A device for permanently ensuring increased moisture content of wood in the timber component below the barrier layer according to one of claims 2 to 10, characterized in that the subterranean component surface is surrounded by a water-impermeable layer, which also hinders the diffusion of water vapor; wherein this layer begins in the region of the barrier layer and ends just before the underside of the subterranean component region, so that at least the bottom side end grain surface is in direct contact with the soil and can absorb water.

14. A device for permanently securing increased wood moisture in the timber component below the barrier layer according to one of claims 2 to 10, characterized in that the subterranean component surface is surrounded by a water-impermeable layer, said layer begins in the region of the barrier layer and just before the underside of the underground Component region ends, so that at least the bottom side end grain surface is in direct contact with the soil and can absorb water.

15. Device according to claim 1 1, characterized in that the water- and gas-impermeable layer comprises a coating material selected from self-adhesive aluminum foil and / or metallized, weather-resistant plastic and / or metallized, weather-resistant composite plastic.

16. Device according to claim 12, which additionally greatly restricts the diffusion of water vapor and gases, characterized in that the water-impermeable layer is a coating material selected from the barrier plastics polyethylene naphthenate (PEN) and / or polyethylene terephthalate (PET) and / or polyvinylidene chloride (PVDC ) having.

17. Device according to claim 13, which is partially permeable to water vapor and gases, characterized in that the water-impermeable layer a

Coating material selected from weather-resistant plastic.

18. Device according to claim 13, which is partially permeable to water vapor and gases, characterized in that the water-impermeable layer a

Coating material of a weather-resistant silicone rubber, preferably a RT V-Si i n c k u nsch uk and particularly preferably a RTV-1 silicone rubber, coated with the envisaged for the cuff component area and then polymerized to a water-impermeable elastic layer.

19. Device according to claim 12, which additionally the diffusion of water vapor and

Severely restricts gases, characterized in that the water-impermeable layer has a coating material made of a weather-resistant silicone rubber, preferably a RTV-Si i n ka uish and particularly preferably a RTV-1 silicone rubber, wherein a strong reduction of the permeability Steam and gases via suitable additives (eg iron mica and / or aluminum flakes) was brought about and is coated with the provided for the cuff component area and then polymerized to a water-impermeable elastic layer.

20. Device according to claim 18, characterized in that the

Coating material is a very low viscosity silicone rubber that penetrates wholly or partially into the wood surface, so that the waterproof layer already begins inside the wood component.

21. Device according to claim 19, characterized in that the

Coating material is a very low viscosity silicone rubber, which penetrates completely or partially into the wood surface, so that the water-impermeable layer already begins in the interior of the wood component and the aggregates advantageously deposited in a dense layer on the wood surface.