BASED ON MAGNESIUM OXIDE

Technical field

The present disclosure relates to the building field. More specifically, this disclosure relates to the building of wooden buildings.

Background art

The background of the present disclosure is hereinafter introduced with the discussion of techniques relating to its context. However, even when this discussion refers to documents, acts, artifacts and the like, it does not suggest or represent that the discussed techniques are part of the prior art or are common general knowledge in the field relevant to the present disclosure.

Buildings primarily made of wood (for example, houses) have become increasingly popular in recent years. This is mainly due to the growing environmental awareness of the people, who prefer wood as a natural and recyclable building material. The wooden buildings guarantee high thermal and acoustic insulation (resulting in improvement of environmental conditions and energy saving). In addition, the wooden buildings are almost completely anti-seismic, and therefore very safe.

Typically, the wooden buildings are built by assembling prefabricated building modules. In this way, the most complex phases of the manufacturing of the building modules are performed in the factory, with only their simple assembly that remains to be executed on site. Consequently, the building of the wooden buildings is very easy and fast, even in inaccessible locations (for example, using cranes or helicopters); furthermore, this makes the building times and costs estimable with minimum elements of uncertainty, and therefore accurate and definite.

The building modules for the wooden buildings may be manufactured with different techniques. Particularly, in the dry technique with wooden frame each building module comprises a structural wooden frame; an internal cavity (or more) of the structural frame is filled with filling material. Two protective structures are fixed on both sides of the structural frame, so as to close its internal cavity. This allows obtaining building modules (even self- supporting, without requiring the use of pillars) in a completely ecological manner (without the use of any adhesive); furthermore, the internal cavities of such building modules make them very simple and quick the laying and the maintenance of the hydraulic and electrical distribution networks of the building.

Each protective structure of the building modules (based on the dry technique with wooden frame) is of multilayer type, with two (or more) distinct protective panels. Particularly, a protective panel of cement-bonded wood fiber (a conglomerate of cement and woodchips, commercially known as Betonyp - trademark) provides the required insulation characteristics and mechanical strength; a protective panel of plasterboard (plaster pressed between two sheets of cardboard) instead provides the required coating characteristics.

However, the different protective panels complicate the manufacturing of the corresponding protective structure (with a consequent increase in the production times and costs of the whole building modules). In addition, this increases the thickness of the building modules and therefore the space occupied by them (with a consequent reduction of the useful space inside the wooden buildings).

Furthermore, the fixing of the protective panels to the structural frame requires the use of cap screws (for crossing all the protective panels up to screw into the wood of the structural frame).

However, the cap screws have a relatively limited hold. Consequently, a quite high number of cap screws is required; this further increases the production times and costs of the building modules.

Moreover, the cap screws are arranged rather close one to another because of their number and size (for example, every 1-2 cm). The cap screws so close together may create cracks in the wood of the structural frame thereby weakening it with consequent risks for the solidity of the building modules (and then for the safety of the whole wooden buildings).

Summary

A simplified summary of the present disclosure is herein presented in order to provide a basic understanding thereof; however, the sole purpose of this summary is to introduce some concepts of the disclosure in a simplified form as a prelude to its following more detailed description, and it is not to be interpreted as an identification of its key elements nor as a delineation of its scope.

In general terms, the present disclosure is based on the idea of using protective panels based on magnesia binder. Particular, an aspect provides a building module for a wooden building comprising two protective panels fixed on opposite sides of a wooden frame, wherein each protective panel comprises a core based on magnesia binder enclosed between two support sheets.

A further aspect provides a wooden building comprising one or more of these building modules.

A further aspect provides a method for manufacturing this building module.

More specifically, one or more aspects of the present disclosure are set out in the independent claims and advantageous features thereof are set out in the dependent claims, with the wording of all the claims that is herein incorporated verbatim by reference (with any advantageous feature provided with reference to any specific aspect that applies mutatis mutandis to every other aspect).

Brief description of the drawings

The solution of the present disclosure, as well as further features and the advantages thereof, will be best understood with reference to the following detailed description thereof, given purely by way of a non-restrictive indication, to be read in conjunction with the accompanying drawings (wherein, for the sake of simplicity, corresponding elements are denoted with equal or similar references and their explanation is not repeated, and the name of each entity is generally used to denote both its type and its attributes - such as value, content and representation). In this respect, it is expressly intended that the figures are not necessary drawn to scale (with some details that may be exaggerated and/or simplified) and that, unless otherwise indicated, they are merely used to illustrate the structures and procedures described herein conceptually. Particularly:

FIG.1 shows a pictorial representation of a building wherein the solution according to an embodiment of the present disclosure may be applied;

FIG.2 shows a partially cut away pictorial representation of a building module according to an embodiment of the present disclosure;

FIG.3 shows a partially cut away pictorial representation of a protective panel of the building module according to an embodiment of the present disclosure;

FIG.4A-FIG.4E show the main steps of a manufacturing process of the building module according to embodiment of the present disclosure; and

FIG.5 shows a partially cut away pictorial representation of a building module according to a further embodiment of the present disclosure. Detailed Description

With reference in particular to FIG. l, a pictorial representation is shown of a building 100 wherein the solution according to an embodiment of the present disclosure may be applied.

Particularly, the building 100 is made of wood (plant material coming from the trunk of the plants); this means that the bearing structure of the building 100 (expressly designed to absorb the loads to which the building 100 is subject during its service life, and in particular its weight) is mainly of wood (with other materials that may be added for a number of functions, such as for insulation, protection, finishing). In the specific case at issue, the building 100 is a (wooden) house intended to be used as a dwelling by one or more families.

The house 100 comprises a foundation 105 (for example, of concrete), which penetrates in the ground to transmit the loads applied thereto by the superstructure in elevation of the house 100. The house comprises walls 110 that extend vertically; the walls 110 being visible in the figure are boundary walls that surround the house 100 (and they are usually load-bearing to support the weight of the house 100 and to discharge it on the foundation 105); the house 100 also comprises partition walls (which subdivide the inner space of the house 100 into the rooms) and ceilings (which cover the rooms at the top), not visible in the figure. A roof 115 covers the house 100 to protect its interior from the atmospheric agents.

Referring now to FIG.2, a partially cut away pictorial representation is shown of a building module 200 according to an embodiment of the present disclosure.

The building module 200 is a (prefabricated) structural component that may be used to make the structure of the above-described house (for example, its walls) by mounting and connecting one to another multiple building modules.

The building module 200 is of (layered) dry type with wooden frame. Particularly, the building module 200 comprises a frame 205 with structural function. The frame 205 is made of wood (for example, Norway spruce of lamellar type). The frame 205 defines an internal cavity, also called square set, 210 (or more). The cavity 210 is filled (at least partly) with a filling material, or filler, 215 (for example, wood fiber); the filler 215 is an insulating filling material that performs an insulating function (thermal and acoustic insulation), and allows the passage of the hydraulic and electrical distribution networks of the house. As described in the following, two protective panels 220a and 220b are arranged on both sides of the frame 205 (so as to close the cavity 210); the panels 220a, 220b are fixed on the corresponding sides of the frame 205 so as to complete the building module 200.

With reference now to FIG.3, a partially cut away pictorial representation is shown of a protective panel of the building module according to an embodiment of the present disclosure.

The protective panel (genetically denoted by the reference 220) comprises a core 305. The core 305 is enclosed between an internal support sheet 3 lOi and an external support sheet 31 Oe, intended to be arranged at a proximal and distal, respectively, position with respect to the frame (not shown in the figure); the support sheets 310i,310e are embedded in the core 305. The core 305 is made of hardened magnesia binder (or Sorel). The magnesia binder is a binder that undergoes a setting phase in contact with the water (producing a plastic mass that is capable of maintaining the given shape), and then undergoes a hardening phase in contact with the air (solidifying with increase of the mechanical strength that is then maintained over time). The magnesia binder is obtained by mixing magnesium oxide (MgO) with magnesium chloride (MgCb) and water (H ₂ 0).

Surprisingly, this allows manufacturing each building module even with only one protective panel 220 per side of the frame (although the addition of further components is not excluded), so as to avoid (or at least limit) the use of multilayer protective structures. Indeed, the above-described protective panel 220 combines high performance of insulation (heat and sound insulation), resistance to fire, water and erosion, permeability to water vapor, at the same time providing many possibilities of surface finishing.

Therefore, the manufacturing of the building modules is simplified, with a consequent reduction of the production times and costs. Moreover, in this way it is reduced the thickness of the building modules and therefore their overall dimensions (with a consequent increase of the useful space inside the buildings).

In an embodiment, the magnesia binder is obtained by mixing magnesium oxide of lightweight type (obtained by firings at low temperatures, such as 18/20 °C) with a concentrated solution of magnesium chloride (and water). For example, the magnesia binder comprises a weight percentage of magnesium oxide equal to 95.00 to 99.50%, preferably equal to 97.00 to 99.25%, and still more preferably equal to 98.00 to 99.10 %, such as equal to 99.00%; furthermore, the magnesia binder comprises a weight percentage of magnesium chloride equal to 0.50-5.00%, preferably equal to 0.75-3.00% and still more preferably equal to 0.90-2.00%), such as equal to 1.00%>.

In an embodiment, each support sheet 310i,310e has a non-compact structure (for example, of fibrous type with thread-like elements crossing one to another). Particularly, each support sheet 3 lOi, 310e may be a (support) mesh. For example, the support mesh 310i,310e is made of fiberglass, with a thickness of 0.50-2.00 mm, preferably 0.75-1.50 mm, and still more preferably 0.90-1.25 mm, such as 1 mm; the support mesh 310i,310e comprises thread-like elements that cross one to another to form meshes with a width of 0.1-3.0 mm, preferably 0.3-2.5 mm, and still more preferably 0.5-2.0 mm, such as 1.00 mm.

In an embodiment, the protective panel 220 as a whole has a thickness of 3-40 mm, preferably 5-30 mm, and still more preferably 10-20 mm, such as 15 mm. For example, the protective panel 220 may have density of 800-1500 kg/m ³ , thermal conductivity of 0.3-0.3 W/mK, bending strength higher than 15 MPa, compressive strength higher than 15 MPa, elastic modulus higher than 5 MPa, impact resistance higher than 3 kJ/m ² , resistance to vapor diffusion of 0.1-30 μ (and therefore equivalent air layer SD of 0.3-120· 10 ^"3 m), immersion water absorption lower than 20%, weighted sound absorption rate aw of 0.5- 0,7, sound insulation of 40-60 dB and incombustibility class Al .

The above-mentioned specifications (either individually or in combination one to another) improve the quality of the protection panel 220.

With reference now to Figure FIG.4A-FIG.4E, the main steps are shown of a manufacturing process of the building module according to embodiment of the present disclosure.

Starting from the plan view of FIG.4A, the cavity of the frame 205 is filled with the filler 215. A peripheral portion of the (external) support mesh 310e is removed, and therefore not visible in the figure. Such peripheral portion of the support mesh 3 lOe covered a peripheral area of the core 305, in correspondence to a peripheral area of the frame 205; for example, the peripheral area of the core 305 is shaped like a frame, which extends from an outer edge thereof with a width equal to 30-70%> (for example, equal to 50%>) of the width of the frame 205 (for example, 3-7 cm). For this purpose, the support mesh 310e is cut so as to separate its peripheral portion. The protective cover 220 is then excavated sideways to remove the peripheral portion of the support mesh 310e; this operation is performed to an extent corresponding to the width of the peripheral portion of the support mesh 310e and to a depth slightly higher than it (for example, 0.5-2 mm), so as to ensure its proper removal. This leaves a remaining area 305 of the core covered by a central portion of the support mesh 310e (denoted with the reference 410c). At this point, the protection panel 220 (with the peripheral portion of the support mesh 310e removed) is laid against the frame 205 flush with it, with the inner support mesh (not visible in the figure) in contact with the frame 205 and the filler 215.

Passing to the side view of FIG.4B, a plurality of staples 415 (only one shown in the figure) are applied to fix the protective panel 220 to the frame 205. Each staple 415 comprises a bar (for example, of steel with a thickness of 0,5-2.0 mm), which is bent into a U-like shape (so as to define a base from which two prongs extend); the bar is of resinated type, i.e., it is covered by a resin layer (for example, of vegetable type).

In detail, as shown in the side view of FIG.4C, the staple 415 is forced (for example, by means of a staple shooting gun) against the peripheral area of the core 305 (outside the central portion 410c of the support mesh). Consequently, the prongs of the staple 415 enter the core 305 and then the frame 205 (until its base abuts against the core 305). This results in a heating (by friction) of the staple 415. As a result, the bar of the staple 415 weakens and its prongs bend (outwards) within the frame 205; at the same time, the resin layer of the staple 415 sticks to the core 305 and to the frame 205. In this way, the staple 415 exerts a high hold that fixes the core 305 against the frame 205 in a stable manner. In addition, thanks to the lack of the support mesh (in the peripheral area of the core 305) the staple 415 directly acts on the core 305; the interaction between the resin layer of the staple 415 and the magnesium oxide of the core 305 considerably increases, even by an order of magnitude, the hold of the staple 415 (as compared to the case of its action on the support mesh).

Passing to the plan view of FIG.4D, the staples 415 are arranged with their lying plane arranged obliquely to a (longitudinal) main axis 420 of the building module 220 (which main axis 420 extends vertically when the building module 220 is mounted in a wall); particularly, the lying plane of each staple 415 forms an angle with the main axis 420 of 30-60°, preferably 35-55°, and still more preferably 40-50°, such as equal to 45°. In this way, the lying plane of each staple 415 forms a similar angle with the grains of the wood of the frame 205 (signs generated by the conducting vessels that flow in the trunk from the roots to the leaves), which grains extend substantially straight (parallel or transverse to the main axis 420) when the wood is cut parallel to the trunk. In this way, the staples 415 intersect the fibers of the wood of the frame 205, thereby further increasing their hold.

The above-mentioned features (either individually or in combination one to another) allow reducing the number of staples 415 (for example, by 2-4 times compared to the case of cap screws), with a consequent further reduction of the production times and costs of the building modules.

Moreover, the reduced number and size of the staples 415 allow further spacing them away (for example, every 3-10 cm, preferably every 4-9 cm, and still more preferably every 5-8 cm, as each every 7 cm); this reduces the risk of creating cracks in the wood of the frame 205, thereby preserving its integrity and consequently its robustness (with positive effects on the safety of the entire buildings).

Passing to FIG.4E, at this point the peripheral portion of the support mesh 310e (denoted with the reference 410p) is laid on the peripheral area of the core 305, so as to cover it and the staples (not visible in the figure any longer). The peripheral portion 41 Op is then fixed again to the core 305 (for example, by adding and hardening further magnesia binder).

Referring now to FIG.5, a partially cut away pictorial representation is shown of a building module according to a further embodiment of the present disclosure.

The building module (differentiated with the reference 500) comprises, in addition to the above-described structure, a barrier (or screen) membrane 505 to water vapor; the barrier membrane 505 is arranged between the frame 205 (and the filler 215) and one of the protective panels (for example, the protective panel 220b) intended to face the interior of the house when the building module 500 is mounted. The barrier membrane 505 is poorly transpirable (i.e., hard to cross by water vapor), for example, with an SD value higher than 10 m, preferably higher than 20 m, and still more preferably higher than 30 m, such as between 10-30 m and 50-100 m (for example, equal to 40 m). For example, the barrier membrane 505 may be made of polyethylene, with a thickness of 0.15-0.3 mm, air mass of 70-150 g/m ² and density of 400-600 kg/m ³ , and with thermal conductivity of 0.3-0.5 W/mK.

The barrier membrane 505 prevents (or in any case limits) the passage of humid air (i.e., mixture of dry air and water vapor generally in amount comprised between 1-3% by mass) from a warmer area to a cooler area through the building module 500; this preserves the interior of the building module 500 from an excess of condensation (generated by the liquefaction of water vapor by cooling). In this way, an improvement of the environmental conditions and a reduction of the deterioration risks of the building module 500 are obtained.

Modifications

Naturally, in order to satisfy local and specific requirements, a person skilled in the art may apply many logical and/or physical modifications and alterations to the present disclosure. More specifically, although this disclosure has been described with a certain degree of particularity with reference to one or more embodiments thereof, it should be understood that various omissions, substitutions and changes in the form and details as well as other embodiments are possible. Particularly, different embodiments of the present disclosure may even be practiced without the specific details (such as the numerical values) set forth in the preceding description to provide a more thorough understanding thereof; conversely, well-known features may have been omitted or simplified in order not to obscure the description with unnecessary particulars. Moreover, it is expressly intended that specific elements and/or method steps described in connection with any embodiment of the present disclosure may be incorporated in any other embodiment as a matter of general design choice. In any case, each numerical value should be read as modified by the term about (unless already done) and each range of numerical values should be intended as expressly specifying any possible number along the continuum within the range (comprising its end points). Moreover, ordinal or other qualifiers are merely used as labels to distinguish elements with the same name but do not by themselves connote any priority, precedence or order. The terms include, comprise, have, contain and involve (and any forms thereof) should be intended with an open, non-exhaustive meaning {i.e., not limited to the recited items), the terms based on, dependent on, according to, function of (and any forms thereof) should be intended as a non-exclusive relationship {i.e., with possible further variables involved), the term a/an should be intended as one or more items (unless expressly indicated otherwise), and the term means for (or any means-plus-function formulation) should be intended as any structure adapted or configured for carrying out the relevant function.

For example, an embodiment provides a building module for a wooden building. However, the building module may be used in any way and in any wooden building (see below).

In an embodiment, the building module comprises a wooden structural frame defining at least one internal cavity. However, the building module may comprise a structural frame of any type (formed either by a single module or by multiple facing, aligned, superimposed modules, each one defining any number of internal cavities, for example, of aligned, matrix-like type); the structural frame may be made of any wood (for example, silver fir), of solid type as well.

In an embodiment, the structural module comprises a filling material filling at least partially said at least one internal cavity. However, the filling material may be of any type (for example, rock wool), and it may fill each internal cavity either completely or partially (for example, with hollows arranged in advance for the hydraulic and electrical distribution networks).

In an embodiment, the structural module comprises a first protective panel and a second protective panel arranged on opposite sides of the structural frame for closing said at least one internal cavity. However, the protective panels may be arranged in any way (see below).

In an embodiment, the building module comprises fixing means for fixing each protective panel on a corresponding side of the structural frame. However, the protective panels may be fixed to the structural frame in any way (see below).

In an embodiment, each protective panel comprises an internal support sheet proximal to the structural frame, an external support sheet distal from the structural frame and a core based on magnesia binder. However, the support sheets may be of any type and the core may be made based on magnesia binder in any way (see below).

In an embodiment, the core is enclosed between the internal support sheet and the external support sheet, with the internal support sheet and the external support sheet being embedded in the core. However, the support sheets may be embedded in the core in any way such as to incorporate them in it (thereby making them integral), for example, with the support sheets completely comprised in the core flush with it (or even more deeply or only slightly protruding, such as for 1-10% of their thickness).

In an embodiment, the core comprises magnesium oxide in a weight percentage equal to 95.00-99.50%. In an embodiment, the core comprises magnesium chloride in a weight percentage equal to 0.50-5.00%). However, the core may have a different composition (for example, with different percentages by weight, volume or mole), even with different, additional or alternative components (for example, magnesium oxide and magnesium sulphate, other calcium or iron chlorides, inert).

In an embodiment, the building module further comprises a barrier membrane for water vapor arranged between the structural frame and the second protective panel. However, the barrier membrane may be of any type; for example, the barrier membrane may have different transpirability (also measured by its resistance to vapor diffusion μ) and it may be made of different material (such as simple or reinforced polyethylene, polyethylene/aluminum, polypropylene/polyethylene/aluminum). In any case, the barrier membrane may be arranged in addition or in alternative between the frame and the other protective panel (facing outwards), or it may even be omitted at all (for example, for use in areas with tempered climate).

In an embodiment, each support sheet is a support mesh. However, the support mesh may be made in any way and of any material (for example, plastic); in any case, different types of support sheets are possible, for example, of nonwoven fabric.

In an embodiment, for each protective panel the external support sheet comprises a peripheral portion (covering a peripheral area of the core in correspondence to a peripheral area of the structural frame) and a central portion, distinct from the peripheral portion (covering a remaining area of the core). However, the peripheral portion and the central portion of the external support sheet may have any shape and size (for example, with the peripheral portion shaped like a grid and the central portion in the form of separate squares).

In an embodiment, the fixing means acts between the core and the structural frame, and they are covered by the peripheral portion. However, the possibility of having the fixing means that acts directly on the external support sheet (of a single piece) is not excluded.

In an embodiment, for each protective panel the fixing means comprises a plurality of resinated staples fixing the core on the structural frame. However, the resinated staples may be in any number and of any type; particularly, each resinated staple may have any shape (for example, arc-like), with the bar of any material (for example, brass) and covered totally or at least partially along its prongs with any resin (for example, of synthetic type). In any case, the possibility of using non-resinated staples or any other fixing element (cap screws as well) is not excluded.

In an embodiment, each resinated staple extends in a laying plane forming an angle of 30-60° with a main axis of the structural frame. However, the lying plane of each staple may extend in any other way (even independently of the grains of the wood).

In an embodiment, the lying plane of each resinated staple forms an angle of 30-60° with a main axis of the structural frame. However, the lying plane of each resinated staple may form any angle with the main axis of the structural frame (zero as well).

Another embodiment provides a wooden building comprising one or more of such building modules. However, the building modules may be used in any number and in any way (for example, for inner walls, ceilings, with exposed finishing, plastered, coated); furthermore, the building may be of any type (with single floor or multiple floors, a school, a hospital).

Generally, similar considerations apply if the building module and the wooden building each has a different structure or comprises equivalent components (for example, of different materials), or it has other operative characteristics. In any case, every component thereof may be separated into more elements, or two or more components may be combined together into a single element; moreover, each component may be replicated to support the execution of the corresponding operations in parallel. Moreover, unless specified otherwise, any interaction between different components generally does not need to be continuous, and it may be either direct or indirect through one or more intermediaries.

Another embodiment provides a method for manufacturing a building module for a wooden building. The method comprises the following steps. A wooden structural frame (defining at least one internal cavity being filled at least partially with a filling material) is provided. A first protective panel and a second protective panel are arranged on opposite sides of the structural frame for closing said at least one internal cavity. Each protective panel is fixed on a corresponding side of the structural frame. Each protective panel comprises an internal support sheet proximal to the structural frame, an external support sheet distal from the structural frame and a core based on magnesia binder; the core is enclosed between the internal support sheet and the external support sheet, with the internal support sheet and the external support sheet that are embedded in the core. However, the building module may be manufactured in any way (for example, with pre-assembled parts).

In an embodiment, said step of fixing each protective panel on a corresponding side of the structural frame comprises, for each protective panel, the following operations. A peripheral portion is removed of the external support sheet covering a peripheral area of the core in correspondence to a peripheral area of the structural frame. The fixing means is applied between the core and the structural frame. The peripheral area of the core and the fixing means are covered with the peripheral portion of the external support sheet. However, these operations may be performed in any way (for example, by covering the peripheral area of the core and the fixing means with a new portion of the support sheet). In any case, the protective panel may be supplied already without the peripheral portion of the external support sheet; furthermore, the possibility of fixing each protective panel directly (without removing any portion of the external support sheet) is not excluded.

Generally, similar considerations apply if the same solution is implemented with an equivalent method (by using similar steps with the same functions of more steps or portions thereof, removing some steps being non-essential, or adding further optional steps); moreover, the steps may be performed in a different order, concurrently or in an interleaved way (at least in part).