FR2700987A1 - Method for treating pieces of wooden framework and device for implementing the said method - Google Patents

Abstract

Method for treating pieces of wooden framework used against wood-eating fungi and other wood parasites by inserting boracid sticks (2) in bore holes (1), in which method, after having made the said bore holes (1) in the piece (4) of wooden framework, the boracid sticks are inserted into each bore hole (1) with a longitudinal spacer piece (5), the said sticks (2) being held at regular intervals inside one and the same bore hole (1) by means of the said longitudinal spacer piece (5) provided with means for keeping the sticks in the spaced-apart condition, the said longitudinal spacer piece (5) being able to be removed from the bore hole (1) together with the sticks (2) in order to check their state.

Description

 The present invention relates to a method of treating structural timber parts against lignivorous fungi and other wood parasites and a device for implementing said method. The invention applies to all types of wood under construction exposed to the weather, in a humid environment or in an atmosphere of condensation, but more particularly to structural pieces of glued laminated wood.

 The development of lignivorous fungi in any building, whatever it is, is always the fact of an excessive humidification favorable to their destructive action. When the origin of the excess moisture is found and it can be removed, conventional fungicide treatment with an organic solvent product is satisfactory. On the other hand, when for reasons of exposure or design of the building, the humidity of the wood cannot be eliminated, a treatment with a product in organic solvent never gives satisfaction, it could possibly delay the action of destruction but does not will be only a palliative: it will then be necessary to consider frequent resumptions.

 There is currently on the market a product based on borates in a solid cylindrical form, hereinafter called boracid sticks, containing a very high amount of active material and having the advantageous property of diffusing in wet wood. This type of treatment particularly concerns wooden structures located outside, sheltered or not, in contact with the ground or in similar situations resulting in permanent or even alternate humidification (the type of fungus involved withstands alternating dryness and humidity ). Wood located indoors in an atmosphere of condensation can be treated by this technique.

 Boracid sticks are introduced into the heart of the wood in wells, the orifice of which is then closed by dowels. The sticks contain a high proportion of boric acid in the form of disodium octaborate (Na2 B8 013) and melt in the wood when the humidity of the latter is more than 25%. Migration takes place in all directions mainly in the longitudinal direction, in a volume of wood proportional to the size and weight of the stick.

 These dimensions are variable and calculated according to the volume of wood to be treated, their diameter is a few millimeters and their length is a few centimeters.

 Up to now in the state of the art, the sticks are introduced individually into the solid woods on the most accessible faces and, in the glued laminated wood elements, over the height, as shown in FIG. 1. A As an example, it is generally necessary to provide 22 to 25 holes per m2 on a glued laminated beam 16 cm thick. The holes are made in staggered rows directed at 450 (see Figure 2), in order to cross the maximum of the bonding plane; the maximum admissible depth of up to 15 cm for a beam 16 cm thick.

 The multiplication of boreholes over the height of the beam has the damaging effect, on the one hand of reducing the resistance of the beam, and on the other hand of detriment to the aesthetics of the construction.

 In addition, the condition of the rods must be checked periodically in the boreholes to determine whether or not they have diffused into the wooden elements and possibly replace them. This requires removing all the plugs that plug the wells and the verification must be done without removing the rods from the wells.

 The present invention proposes to remedy these drawbacks by defining a method of treating wooden frame pieces making it possible to limit the number of boreholes to have the least possible orifice to be closed and to affect it in the least harmful way possible. the aesthetics of contruction. Another object of the present invention is to facilitate the control of the state of boracid sticks in the heart of the wood.

To do this, the subject of the present invention is a method of treating structural timber parts used against lignivorous fungi and other wood parasites, characterized in that it comprises the following successive steps:
- drill wells at regular intervals in a structural part in
wood to be treated,
- insert boracid sticks into each wellbore with a member
of longitudinal spacing, said boracid rods being kept at
regular interval within the same wellbore using said
longitudinal spacing member provided with rod retaining means
in spaced condition, said longitudinal member being able to be extracted from the well of
drilling with said rods to check their condition,
- close each wellbore with removable waterproof plugs.

 Advantageously, the longitudinal member comprises a rod of length less than the depth of the wellbore along which are fixed, at regular intervals, platforms on which the boracid rods rest, the diameter of the platforms being less than the diameter of the borehole.

 The advantage of using such a member is to be able to introduce several rods into the same wellbore. We can therefore practice deeper piercings than in the prior art and in fewer numbers. The spacing between each stick of the same well is calculated in advance according to the volume of wood to be treated.

 The control of the state of the rods and their replacement is thereby facilitated by the extraction of the member along which the rods are arranged, after removing the plug plug.

 Deep holes also make it possible to reach parts of the wooden frame which are difficult to access such as built-in parts.

 According to an additional particularly advantageous characteristic, the drilling of the wells is carried out, preferably, from the lower surface and / or the upper surface of the piece of wooden frame, when the latter consists of strips of wood. glued.

 Most of the structural pieces currently used consist of glued wooden strips. In order for the treatment to be as effective as possible, it is necessary to cross all the bonding planes to facilitate the diffusion of active material from the sticks.

 Until now, it was necessary to provide 22 to 25 holes per m2 for a glued laminated wood element and these are made on the height of the element (see Figure 1).

With this new process, the holes are made perpendicular to the bonding planes from the lower surface or the upper surface, or only over half the height of the element by alternately drilling the upper surface and the lower surface. . It suffices from four deep wells which extend over the height of the element (instead of 25 in the prior art) to treat an m2.

 Advantageous consequences linked to the reduction in the number of wells are manifested on a technical but also aesthetic level: the resistance of the element is less affected by a reduced number of holes and there is also an aesthetic gain by avoiding the screening of the element by a multitude of pegs.

 Other characteristics, advantages and peculiarities of the invention will emerge from the description which follows, given with regard to the appended drawings and giving by way of indication but not limitation an embodiment of the invention.

In the drawings:
- Figure 1 is a perspective view of a section of structural member in
glued laminated timber on which we drilled for insertion
unitary of boracid sticks, as described by the prior art,
- Figure 2 is a sectional view of the glued laminated timber frame element
of FIG. 1 along a section plane vertically by wells,
according to the technique of the prior art,
- Figure 3 shows part of a glued laminated timber frame element
similar to that of FIG. 1 on which the method of the
present invention,
- Figure 4 is a perspective view of the longitudinal spacer
used for implementing the method of the present invention,
- Figure 5 is a sectional view of part of a spacer
introduced into a wellbore according to the present invention,
- Figure 6 is a sectional view of a piece of glued laminated timber frame
treated according to the method of the present invention,
- Figure 7 is a sectional view of a restricted part of a structural part
made of glued laminated timber treated according to the present invention by drilling a well
drilling from the lower surface,
- Figure 8 is a sectional view of a portion of wooden beam embedded in
a masonry element and treated according to the present invention.

 The treatment by insertion of boracid sticks mainly concerns wooden structures made outside, and first of all glued laminated timber structures.

This is why the various exemplary embodiments mostly use pieces of glued laminated wood. But of course, the treatment method described below is applicable to any wooden construction, whatever it may be.

 Figures 1 and 2 have already been the subject of a comment during the exhibition of the technique of the prior art. The glued laminated wood beam illustrated in FIG. 1 has a thickness e of 16 cm for a height h of 120 cm. For the insertion of the rods 2, holes were made on the height h of the beam, each hole containing a single boracid rod. In order to pass through as many gluing planes as possible, the holes are inclined, as shown in section in Figure 2.

 Referring now to FIG. 3, the present invention defines a method for treating pieces of wooden frame by inserting boracid sticks 2 into wells 1. The piece of wood in question in FIG. 3 is a beam 4 of glued laminated wood similar to that of Figure 2.

 The method of the present invention comprises several steps, the first of which is the drilling of wellbore 1 in the height direction of the beam, perpendicular to the bonding planes 43. This is one of the main characteristics of the present invention, because it makes it possible to reduce the number of piercings by making deeper piercings. In FIG. 3, the hole 1 is made from the upper surface 41 of the beam 4 and extends to the last lamella constituting the lower surface 42 of the beam 4. The diameter of the hole 1 depends on the diameter sticks 2 necessary to treat the desired volume of wood. For example, the diameter of the rods vary from 6 to 18 mm.

 Figure 3 shows only one wellbore 1, as the view has been intentionally enlarged to show more detail of the design details.

But it goes without saying that similar and parallel holes are made at regular intervals from the upper surface and / or the lower surface of the beam, in order to cover the total volume of the latter as illustrated in FIG. 5. Indeed, as previously stated, boracid sticks have the property of diffusing into wood with a humidity greater than 25% with a diffusion radius proportional to their size.

 The second step of the process consists in introducing boracid rods 2 into the wellbore 1 with a longitudinal spacing member 5 composed of a resistant, stainless and rot-proof rod 51 of metal or any other material, along which are fixed , at regular intervals, circular platforms 52 on which the boracid rods 2 rest. The length of the rod 51 is less than the depth of the wellbore 1 and the diameter of the circular platforms 52 is less than the diameter of the well. drilling for obvious reasons. The rod 51 is pressed against the wall of the wellbore by the action of circular platforms 52. The spaces between each platform 52 and consequently between each stick 2 are determined by calculation as a function of the size of the stick 2 and the volume of wood to be treated.

 At one end, the rod 51 is bent to grip it in order to easily introduce or extract the spacer 5 with said rods 2. The insertion of the rods 2 in the wellbore is therefore carried out. 'One after the other by positioning them on their respective platforms 52 as one inserts the spacer 5 in the wellbore. As for the control of the state of the rods which must be carried out periodically, it is carried out by extraction of the rods 2 by pulling on the spacer member. This control operation is considerably simplified for two reasons relating to: on the one hand to the reduced number of wells and on the other hand to the possibility of extraction of the sticks of their wells.

 The last step consists in closing the wellbore by means of a removable waterproof plug 6, for future checks.

 Figure 4 is a perspective view of a spacer 5 similar to that of Figure 3, with four circular platforms for receiving the rods. The number, size and spacing of the platforms 52 vary depending on the depth of the wellbore that can be drilled and the volume of wood to be treated.

 According to one embodiment of the spacer 5, the platforms 52 are welded at right angles, at regular intervals along the rod 51, as shown in FIG. 4.

 According to another preferred embodiment, the platforms 52 are removable and are not placed on the rod 51 until their spacing has been determined according to the characteristics of the structural member to be treated. For this, under each plate -frome is fixed a tail 53 which is inserted into a ring 54 fixed along the rod 51 as shown in Figure 5. Advantageously, the end of the tail 53 protrudes from the ring 54 and can be bent if the 'We want to keep the platform 52 fixed.

The rings 54 are fixed along the rod 51 relatively tightly in order to be able to select the desired spacing between each platform as a function of the length of the sticks 2. The rings 54 which are not used can be crushed on the rod 51 to leave enough space in the wellbore 1 for positioning the rods 2.

 fi is also possible to provide a platform 52 at each end of the rods 2 to obtain with certainty an exact positioning and locked in the place provided in the wellbore 1.

 According to the present invention, the method also provides for drilling the holes alternately from the upper surface and the lower surface, perpendicular to the bonding planes 43 as shown in FIG. 6. Although the number of holes 1 is doubled (8 openings per m2 for a beam similar to that of figure 2), this allows a better distribution of openings and certainly a less weakening of the resistance of the beam 4. However, the choice between alternative openings or on the same side will generally be determined according to criteria relating to the way the beam is implemented and its exposure, for the sake of aesthetics.

 The spacers 5 used for the insertion of the boracid rods 2 from the lower surface 42 of the beam are identical to those used for the upper rods, except that they have a platform 52 additional to proximity of the curved part of the rod 52 since the spacers are introduced head to tail in the boreholes of the lower surface 42. They are then held in place only by the removable pin 6 closing the well of drilling 1.

 To reach the effective doses in a given volume of wood, it is sometimes necessary to combine the stick with the product in its liquid form. The product is then able to penetrate dry wood on the one hand, and on the other hand allows to start the diffusion of the stick by transporting the active ingredients in the wood when the humidity is temporarily insufficient.

 Consequently, when drilling 1 is carried out from the upper surface 41, the liquid product is poured by gravity. On the other hand, when drilling 1 is carried out from the lower surface 42, it is injected under pressure from a channel 7 drilled near the wellbore 1 and communicating with it, as shown in FIG. 6 .

 The orifice of the channel 7 is then closed with a dowel.

 The method of the present invention can also be implemented in constructions requiring the embedding of glued laminated wooden beams and the like in masonry elements subject to water infiltration. In Figure 8, there is shown a beam 4 whose end is embedded in a wall 9 of concrete. Even if the beam is not directly exposed to the weather or any other humid environment, its end can still develop lignivorous fungi.

 By a hole 1 diagonally extending in the recessed area of the beam 4, it is possible to effectively treat this hardly accessible part, and this whatever the length of the recessed beam by varying the angle of the piercing.

 Although the embodiments described above only deal with wooden frame parts, the present method can possibly find its application in the context of a treatment of a stone wall or floor exposed to humidity favoring the development of fungi and other stone parasites. After drilling the stone, the spacing member 5 can be used in the same way to introduce sticks of fungicidal products which diffuse in the mass of the stone.

Claims (8)

Claims  1.- Method for treating wooden frame parts used against lignivorous fungi and other wood parasites, characterized in that it comprises the following successive stages:  - drill wells (1) at regular intervals in a part (4) of  wooden frame to be treated,  - insert boracid sticks (2) in each wellbore (1) with a  longitudinal spacing member (5), said boracid rods (2) being  maintained at regular intervals inside the same wellbore (1) at  means of said longitudinal spacer provided with retaining means  (52) rods in spaced condition, said longitudinal member (5) being able  be extracted from the wellbore (1) with said rods (2) to control their  state,  - close each wellbore (1) using waterproof plugs (6)  removable.  2. A treatment method according to claim 1, in which the longitudinal member (5) comprises a rod (51) of length less than the depth of the wellbore (1) along which are fixed, at regular intervals, platforms (52) on which the boracid rods (2) rest, the diameter of the platforms (52) being less than the diameter of the wellbore (1).  3.- A treatment method according to claim 1 or 1 claim 2, wherein the boreholes of the wellbore (1) are preferably made from the lower surface (42) and / or the upper surface (41 ) of the part (4) of wooden frame, when the latter consists of glued wooden strips.  4. A treatment method according to claim 1, claim 2 or claim 3, further comprising the step of filling the boreholes (1) with a liquid product promoting the dissolution of the rods (2) and the diffusion of their active ingredients.  5. A treatment method according to claim 4, in which the liquid product is injected under pressure through an injection channel (7) drilled near the wellbore (1) and communicating with it, when the bottom of said wellbore is located at a higher level than the orifice thereof.  6.- Device for the treatment of wooden frame pieces used against lignivorous fungi or other wood parasites by insertion of boracid sticks (2) in boreholes (1) made in the frame piece (4) wooden, characterized in that it comprises a longitudinal spacing member (5) provided with retaining means (52) of the boracid rods (2) in spaced condition inside a wellbore (1), said longitudinal spacing member (5) being able to be inserted and extracted from the wellbore (1) with said boracid rods (2) to check their condition.  7.- Device according to claim 6, wherein the longitudinal spacer (5) comprises a rod (51) of length less than the depth of the wellbore (1) along which are fixed, at regular intervals , platforms (52) intended to receive the boracid rods (2), the diameter of the platforms (52) being less than the diameter of the wellbore (1).  8.- Dispositf according to claim 6 or claim 7, wherein the platforms (52) are removably attached to the rod (51), each platform (52) being provided with a tail (53) s' extending at right angles under said platform, said tail fitting into a ring (54) fixed along the rod (51).