JP2002161623A - External-facing backing structure and external-facing backing construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a quite new semi-drying and semi-wet type external facing backing structure in which not only design properties, maintainability and reproducibility but also workability and quality characteristics are improved. SOLUTION: The external-facing backing structure contains a cement board layer 3 supported on the outside of an exterior-wall skeleton layer 1 and a cement mortar layer 4 applied on the external side face of the cement board layer 3. The cement board layer 3 is constituted by laying and arranging a plurality of cement boards 3a, 3a and the like in a plane shape, joints 3b are filled with cement mortar, and the cement board layer 3 is covered with a glass fiber net 4a from the outsides of the joints. Both surfaces of the cement board layer 3 are reinforced by the glass fiber nets, and irregularities are formed to the external side face of the cement board layer 3. A ventilation space layer 2 is formed between the exterior-wall skeleton layer 1 and the cement board layer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exterior foundation structure and an exterior foundation method for forming an exterior foundation of a building with semi-dry and semi-moist.

[0002]

2. Description of the Related Art Exterior construction methods for relatively low-rise buildings, such as detached houses, which are relatively small and medium-rise buildings, include a wet construction method including a step of applying a wet material mixed with water on site, and a method using no wet material. Can be roughly divided into dry construction methods in which siding and the like are attached to the skeleton. In the wet method, there are many on-site operations such as water mixing and plastering of plastering materials, and the finish is greatly affected by the skill level and morals of the workers. Therefore, there is a tendency that the workability is inferior to that of the dry method with less variation in finish, and it is difficult to ensure the quality.

However, siding or the like used as a finishing material in the dry method is difficult to pass over a pseudo-like design merely imitating the design of an exterior surface such as a stone material, a tile, and a painted wall by a wet method. Because it is a factory product, there are few design variations. In addition, since the dry method uses a dry material that has the functions of both a base material and a finishing material, if the finish surface becomes dirty, discolored, faded, etc. Not only is it inferior, but in some cases trying to reproduce the original finish, the dry wood itself has been discontinued.

[0004] On the other hand, the wet method is extremely excellent in design, for example, it is possible to achieve a high-grade finish, and there is a wide variety of design variations regardless of the finishing material. Moreover, with respect to aging deterioration such as stains, discoloration, fading, etc. of the finish, it is only necessary to replace the finish while leaving the base as it is, so it is excellent in maintainability, and since the finishing material is prepared on site, the original finish Can be easily reproduced. Therefore, even though the workability and quality are inferior to the dry method, there is still a strong need for a wet method excellent in design, maintainability and reproducibility.

[0005] FIG. 7 illustrates an exterior structure of a wooden building by a wet construction method. In the wet exterior structure shown in the figure, a moisture-permeable waterproof sheet 2b is attached to the outer surface of a structural plywood 1c located on the outermost side of the outer wall skeleton layer 1, and the body edges 2a, 2a,.
, A waterproof paper 5 and a lath net 6 are fastened, and a cement mortar 7 is further applied. Finally, the cement mortar 7 can be used as a base adjustment surface, on which various finishing layers S such as spraying, tile application, and stone application can be applied.

In the wet exterior structure illustrated in FIG. 8, a moisture-permeable waterproof sheet 2b is attached to the outer surface of the structural plywood 1c, and the plywood 8 is beaten through the body edges 2a, 2a,. Waterproof paper 5 and lath net 6 are fastened to the side and cement mortar 7 is applied. The point that the finishing material applied on the cement mortar 7 is not selected is the same as in the case of FIG. In these wet exterior structures, a ventilation space A is formed between the rims 2a.

[0007]

However, these wet exterior structures or construction methods have the following problems in workability and quality as described above.

(1) Problems caused by a large coating thickness of the cement mortar 7 In order to provide the outer wall shown in FIGS. 7 and 8 with a predetermined fire protection performance, it is necessary to apply the cement mortar 7 to a considerably large thickness. For example, in order to make this outer wall a fire-resistant structure in accordance with the Building Standards Law, a lath mesh 6 and a cement mortar 7
It is necessary to secure a thickness of 20 mm only with the layer alone (Article 108, item (ii) of the same enforcement order). And, in order to secure such a coating thickness of the cement mortar 7,
In addition to requiring the labor and skill of work, such as the need to apply cement mortar 7 in three steps of intermediate coating and finish coating, or in two steps of undercoating and topcoating, work and curing Is also prolonged, and it becomes difficult to control the coating thickness. Further, in the case of FIG. 8, the thickness of the outer wall is particularly increased due to the presence of the plywood 8, so that an extra sash trimming material is newly required, and it is difficult to secure the retreat distance from the road boundary line or the adjacent land boundary line. Incurs significant disadvantages in cost and design.

(2) Problems associated with the use of lath net 6 In order to prevent the neutralization of cement mortar 7, lath net 6
7 and 8 because the work for fastening the waterproof paper 5 and the lath net 6 and the work for applying the cement mortar 7 belong to the same construction section (plaster) in customary practice.
In the wet exterior construction method shown in
It is not possible to precede only the operation of attaching the waterproof paper 5 and the lath net 6 in a form separated from the application operation of the above. In addition, the application and curing of the cement mortar 7 must be carried out at a different period from the internal construction work involving vibration such as the plaster board affixing to the wall surface. Therefore, inevitably, a period in which the fastening operation of the waterproof paper 5 and the lath net 6 and the application operation of the cement mortar 7 are performed as a series of operations independently of other works must be secured during the entire process. This is a factor that hinders shortening of the construction period.

(3) Problems in Forming Vent Space A In the wet exterior construction method shown in FIG. 7, the waterproof paper 5 is ventilated as shown in FIG. It sinks into the space A side. Therefore, in order to secure the regular cross-sectional area of the ventilation space A even in such a portion, it is necessary to increase the thickness of the body edges 2a, 2a,. However, the thickness of the outer wall becomes large, and an extra sash is required, and it is difficult to secure a retreat distance from a road boundary line or a neighboring land boundary line. Further, since it is necessary to finish the surface of the cement mortar 7 smoothly even in the portion where the waterproof paper 5 sinks into the ventilation space A side, the coating thickness of the cement mortar 7 becomes extremely large in that portion and the material is Waste of time and construction time. In order to suppress the sinking of the waterproof paper 5, the waist edges 2a, 2a,.
Installation intervals must be shortened, which in turn requires labor and cost.

(4) Problems associated with the use of plywood 8 In the wet-type exterior structure shown in FIG.
Since the plywood 8 is struck on the outside of the a,.
There is a quality problem in that the plywood 8 absorbs moisture and corrodes due to rainwater invaded from around the pinholes and sashes and moisture originally contained in the cement mortar 7. Further, the plywood 8 may warp due to such moisture absorption (warping of the plywood 8), and the lath net 6 fastened to the plywood 8 may undergo the behavior and crack the cement mortar 7 in some cases.

(5) Problems when the outer wall is curved When the outer wall is curved, in the wet-type exterior structure shown in FIGS. 7 and 8, the rims 2a, 2a,. It is extremely difficult and troublesome to fasten the hard lath net 6 while bending it along the plywood 8 which is bent into a curved surface, and as a result, the cement mortar 7 has a constant thickness so as to form a smooth curved surface. It is also difficult to smear.

Therefore, the present invention solves such problems in the workability and quality of the wet exterior structure or the construction method, and improves not only the designability, the maintainability, and the reproducibility but also the workability and the quality. The present invention proposes a completely new semi-dry semi-humid type exterior base structure or construction method.

[0014]

That is, the invention according to claim 1 comprises a cement board layer supported on the outside of the outer wall frame and a cement mortar layer applied on the outer surface of the cement board layer. An exterior base structure characterized by comprising:

[0015] Such an exterior base structure is constructed so that a cement mortar layer is formed on the outside and various finishes such as spraying, tile application, and stone application can be performed thereon. As in the case of the wet-type exterior structure described above, the design, the maintainability, and the reproducibility are extremely excellent. Nevertheless, since the inside of the cement mortar layer is made of a cement board (industrial product) that has the same main component as the cement mortar and easily adheres to the cement mortar, the whole structure has a semi-dry and semi-moist structure. In order to obtain the same fire protection performance as the wet exterior structure of the above, the thickness of the cement mortar applied on site can be reduced. Therefore, it is possible to reduce the on-site work, shorten the work / curing period, and homogenize the finish. In particular, the outer wall thickness can be reduced as compared with the wet exterior structure shown in FIG.
This is advantageous in terms of design.

Further, since a lath net is not used as a coating base of the cement mortar layer, there is no problem of rust,
In the form separated from the cement mortar layer application, only the cement board layer application can proceed in advance.
Therefore, if the construction of the cement board layer is advanced in parallel with the internal construction work or the like, it is possible to shorten the entire construction period. Furthermore, since the cement board is an inorganic material, there is no danger of moisture absorption and corrosion unlike plywood, and there is no danger of quality deterioration over time. In addition, since bleeding does not occur due to moisture absorption unlike plywood, cracks are less likely to occur in the outer cement mortar layer.

According to a second aspect of the present invention, there is provided the exterior base structure according to the first aspect, wherein the cement board layer is formed by laying a plurality of cement boards in a plane, and joints between the cement boards. Characterized by being filled with cement mortar.

In this exterior base structure, the cement mortar is filled in the joints between the cement boards laid out in a plane, so that not only the cement boards are firmly integrated, but also the joints between the cement boards have the outer wall. Fire protection performance does not decrease. If the joint width is too small, the cement mortar cannot be filled properly.On the other hand, if the joint width is too large, if there is a ventilation space behind the cement board, the cement mortar pushed in from the outside will fall there, There are adverse effects such as blocking the mouth. From such a viewpoint, the joint width is preferably about 2 mm.

According to a third aspect of the invention, there is provided the exterior base structure according to the second aspect, wherein the joint is covered with a glass fiber net from the outside.

[0020] In such an exterior base structure, since the joint portion which is susceptible to stress concentration is reinforced by a glass fiber net having a large tensile strength, it is effective to crack the cement mortar layer which is weak in tension into the joint pattern of the cement board. Can be suppressed. Since the glass fiber net is an alkali-resistant material, it does not corrode even when embedded in cement mortar, and since it is a heat-resistant material, its strength does not decrease even in a fire.

According to a fourth aspect of the present invention, there is provided the exterior base structure according to any one of the first to third aspects, wherein both surfaces of the cement board layer are reinforced by a glass fiber net. It is characterized by.

In this exterior base structure, since the both sides of the cement board layer are reinforced with glass fiber nets to improve the bending strength and the shear strength of the cement board layer, the cement board layer is cracked during transportation or on-site processing. And chipping can be prevented. Also, if the outer wall skeleton is curved, rather than bending a hard lath net according to its curvature,
Since it is easier to bend a cement board reinforced on both sides by a glass fiber net, a curved wall can be finished easily and neatly. Since the glass fiber net is an alkali-resistant material, it does not corrode even when it comes into contact with cement mortar, and since it is a heat-resistant material, its strength does not decrease even in a fire. Of course, from the viewpoint of reducing on-site work and ensuring quality, it is desirable that the glass fiber net is embedded when the cement board is manufactured.

According to a fifth aspect of the present invention, there is provided the exterior base structure according to any one of the first to fourth aspects, wherein unevenness is formed on an outer surface of the cement board layer. Features.

In such an exterior underlayer structure, since the contact area between the cement board layer and the cement mortar layer is large, the exterior underlayer structure is such that both layers are firmly and integrally attached. In addition, from the viewpoint of reducing on-site work and ensuring quality, it is desirable that the formation of the unevenness is performed at the time of manufacturing the cement board.

According to a sixth aspect of the present invention, there is provided the exterior base structure according to any one of the first to fifth aspects, wherein a ventilation space is formed between the outer wall frame and the cement board layer. It is characterized by becoming.

In this exterior base structure, since a ventilation space is formed between the outer wall skeleton and the cement board layer, dew condensation in the wall can be effectively prevented. At this time, since the cement board layer has such a rigidity that it does not sink by the iron pressure at the time of applying the cement mortar,
No cross-sectional defects of the ventilation space occur behind the cement board layer.

Further, the invention according to claim 7 is a step of attaching a cement board to the outside of the outer wall frame, and applying a cement mortar prepared by adding water or a polymer emulsion to a premix mortar on the outer surface of the cement board. And an exterior underlaying method.

This exterior base construction method is a construction method for realizing the exterior base structure according to claim 1, wherein cement and fine aggregate are prepared in advance instead of preparing cement and fine aggregate on site. In addition, since premixed mortar, which requires only addition of water or a polymer emulsion, is used on site, work on site can be reduced and quality can be easily secured.

Further, the invention according to claim 8 is a step of attaching a plurality of cement boards so as to be laid out on the outside of the outer wall frame, and a step of swelling at a height of 5 mm or less from the outer surface of the plurality of cement boards. Filling a joint between the plurality of cement boards with cement mortar prepared by adding water or a polymer emulsion to a premix mortar, and embedding a glass fiber net in the peak, so as to form a portion, Applying the cement mortar to the outer surface of the cement board using a top end of the peak as a ruler.

This exterior base construction method is a construction method for realizing the exterior base structure according to claim 3, and is used to fill a joint between a plurality of cement boards with cement mortar along a joint line. Since the crest is formed and the glass fiber net is embedded in the crest, joint reinforcement by the glass fiber net is quickly and reliably performed. Further, since the cement mortar is applied using the top end of the mountain as a ruler, the application work on site is simplified, and the control of the coating thickness is also facilitated.

[0031]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description, the same elements will be denoted by the same reference symbols, without redundant description.

1. Exterior Base Structure FIG. 1 is a partially cutaway perspective view illustrating an embodiment of an exterior base structure according to the present invention. As shown in the figure, this exterior foundation structure by the framed wall construction method comprises four layers of an outer wall skeleton layer 1, a ventilation layer 2, a cement board layer 3, and a cement mortar layer 4 in order from the inside, and further, a cement mortar layer. Various finishings such as spraying, tile application, stone application, and the like can be applied as a finishing layer S on the surface 4. The contents of each layer are as follows.

(1) Outer wall frame layer 1 The outer wall frame layer 1 is composed of vertical frames 1a, 1 arranged at regular intervals.
are constituted by sandwich panels sandwiching a,... between the plaster board 1b and the structural plywood 1c from both sides, and function as load-bearing walls in the frame wall construction method. Glass wool 1d as a heat insulating material is filled between the vertical frames 1a. However, the “outer wall frame” in the present invention is not limited to such a configuration. For example, it may be assembled on site instead of a panel produced in advance in a factory,
It does not need to be a bearing wall. Of course, it is not limited to the frame wall method, but may be an outer wall of a conventional frame method.

(2) Vent Layer 2 The permeable layer 2 is provided with vertical frames 1a, 1 via a structural plywood 1c.
a, ... are nailed with the rims 2a, 2a,.
a, 2a, ..., cement board 3 outside
are formed by attaching a, 3a,... with a wood screw. Ventilation space A which is a space surrounded by structural plywood 1c, body edges 2a, 2a and cement board 3a.
Is connected to an intake port (not shown) below and to an exhaust port (not shown) above, and serves to prevent air condensation in the wall by securing vertical air flow in the outer wall. In addition, since the moisture-permeable waterproof sheet 2b is attached to the outer surface of the structural plywood 1c here, it is possible to prevent moisture absorption and decay of the outer wall skeleton layer 1 due to infiltration of water into the ventilation space A, and to generate indoors. This moisture can be discharged outside through the outer wall frame layer 1 and the ventilation space A. However, the "ventilation space" in the present invention is not limited to such a configuration. For example, the body edges 2a, 2a,. It may be something. Further, after attaching an appropriate waterproof sheet to the outer surface of the outer wall frame layer 1, the cement boards 3a, 3
may be directly attached to eliminate the ventilation space A itself.

(3) Cement board layer 3 The cement board layer 3 is a coating base of the cement mortar layer 4 and is attached by a wood screw so as to be laid flat on the outside over the body edges 2a, 2a,. , A plurality of cement boards 3a, 3a,. Since the cement board 3a has a certain degree of unevenness on its outer surface, it can hold a cement mortar having a certain thickness without a lath net. In addition, the cement board 3a is an inorganic material and does not have the possibility of moisture absorption corrosion and bleeding unlike plywood, and thus contributes to the improvement of the quality of the outer wall such that cracks hardly occur in the cement mortar layer 4 on the outside thereof.

Further, since the cement board 3a has substantially the same composition as the cement mortar constituting the cement mortar layer 4, even if the thickness of the cement mortar layer 4 to be constructed on site is small, the cement board layer 3 and the cement mortar The entire outer wall combined with the layer 4 can ensure the same fire protection performance as when cement mortar is applied with a certain thickness or more. That is, instead of trying to secure the fire protection performance of the outer wall only with the cement mortar layer 4 constructed on site, a cement board layer composed of cement boards 3a, 3a,. By making a semi-dry and semi-moist structure in which a cement mortar layer 4 constructed on site is superimposed on 3
Since the fire protection performance is ensured by the combined thickness of these two layers, the coating thickness of the cement mortar layer 4 at the site can be small, reducing the on-site work, shortening the period of work and curing, and homogenizing the finish. Can be achieved.

2 (a) showing a vertical joint portion and FIG. 2 (a) showing a horizontal joint portion.
As shown in (b), the joint 3b between the cement boards 3a, 3a is filled with the same cement mortar as the cement mortar layer 4, and the thickness of the cement mortar at the joint portion is insufficient and the fire prevention performance is impaired. Not secured. Further, the cement mortar filled in the joints 3b also plays a role of firmly connecting the cement boards 3a, 3a to each other and forming a strong cement board layer 3. Incidentally, it is desirable that the width of the joint 3b be about 2 mm. If it is too small, the cement mortar cannot be filled well, while if it is too large, the vertical joint without the back edge 2a (FIG. 2 (b))
This is because there is an adverse effect such as that the cement mortar pushed from the outside falls into the ventilation space A and blocks the intake port.

As shown in FIG. 3, the cement boards 3a, 3a,... Are arranged in a staggered manner by being horizontally attached, and joints 3b constituting a vertical joint portion are located at the center of the trunk edge 2a. Cement boards 3a, 3 in the present invention
are not limited to this. For example, the cement boards 3a, 3a,... may be vertically attached or jointed to form a potato joint. In addition, as described later, the joint 3b is covered and reinforced with a glass fiber net 4a on the outside.

Further, since glass fiber nets (not shown) having a large tensile strength are embedded on both the inner and outer surfaces of the cement board 3a, the bending strength and the shear strength of the cement board 3a are remarkably higher than those of a normal cement board. In addition to being hard to be broken or chipped during transportation or on-site processing, even when the outer wall skeleton layer 1 has a curved surface, the cement board 3a is formed in accordance with the curvature.
Can be bent smoothly. Since the glass fiber net is an alkali-resistant material, it does not corrode even when it comes into contact with cement mortar, and since it is a heat-resistant material, its strength does not decrease even in a fire. Of course, from the viewpoint of reducing on-site work and ensuring quality, it is desirable that the glass fiber net is embedded when the cement board is manufactured.

Further, the outer surface of the cement board 3a is subjected to unevenness processing (roughening processing: not shown),
Since the contact area between the cement board layer 3 and the cement mortar layer 4 is large, both layers are firmly and integrally attached. Of course, from the viewpoint of reducing on-site work and ensuring quality, it is preferable that the unevenness is formed at the time of manufacturing the cement board 3a, but the unevenness may be formed on-site.

(4) Cement Mortar Layer 4 As described above, the cement mortar layer 4 is made of cement mortar that is constructed on site, and is provided to maintain the design, maintenance, and reproducibility equivalent to those of a conventional wet structure. Various finishes such as spraying, tiled, stoned, etc. can be applied to this.
Further, since the coating base of the cement mortar is the cement board layer 3, the lath net does not rust and the neutralization of the cement mortar layer 4 does not progress unlike the conventional wet structure.

Further, the cement mortar layer 4 is formed on the cement board 3 constituting the cement board layer 3 inside thereof.
It includes a glass fiber net 4a for reinforcing a joint 3b between a and 3a from outside. The glass fiber net 4a is in the form of a tape having a constant width extending over both sides of the joint 3b, and its high tensile strength reinforces the joint 3b subjected to stress concentration, so that the cement mortar layer 4 which is weak in tension is broken along the joint 3b. Is preventing that.

2. Exterior Base Construction Method The construction procedure of the exterior base structure shown in FIG.
This will be described with reference to FIG. It is assumed that the construction of the outer wall skeleton layer 1 has been completed.

(1) Striking the rim First, as shown in FIG. 4A, in order to form the ventilation space A outside the outer wall frame layer 1, a moisture-permeable waterproof sheet 2b is provided on the outer surface of the structural plywood 1c. Attached, and the vertical frames 1a, 1a,
Are fixed along the vertical direction by nails or the like. For the portion without the vertical frame 1a, the body edge 2a is fixed to the structural plywood 1c with wood screws or wood screws. This step is omitted when the ventilation space A is not formed.

(2) Cement board attachment Next, as shown in FIG. 4 (b), cement boards 3a, 3a,... Are horizontally staggered along the outer sides of the trunk edges 2a, 2a,. (See FIG. 3). At this time, using an electric screwdriver with an impact function, the cement board 3a is fixed to the rim 2a by a rust-proof wood screw. When the cement boards 3a, 3a,... Are partially divided, the cement boards 3a are cut with an electric saw. In addition, for a portion that does not require the ventilation space A, such as the inside of the sleeve wall of the balcony, an appropriate waterproof sheet is attached to the outer wall frame layer 1, and then the cement boards 3a, 3a
Paste directly.

(3) Application of Primer Subsequently, a primer for firmly adhering the cement board layer 3 and the cement mortar layer 4 is prepared, and the primer is applied to the outer surface of the cement board layer 3 with a brush or a roller. .

(4) Preparation of Cement Mortar Next, a cement mortar for filling the joints 3b between the cement boards 3a, 3a and forming the cement mortar layer 4 is prepared. This cement mortar is pre-mixed with a certain amount of cement, fine aggregate, resin fiber, etc. in advance in a bag from the viewpoint of reducing on-site work and ensuring quality. Although a mixed type is desirable, it may be prepared entirely on site. The kneading of the cement mortar uses a mortar mixer instead of a hand mazer. This is because high-speed kneading with a hand maze causes problems such as the generation of many air bubbles to lower the strength of the cement mortar and the possibility that resin fibers are entangled with the blades to cause lumps. In addition, the cement mortar is rich in elasticity due to the compounding of the resin fibers, and is less likely to crack.

(5) Filling Joints As shown in FIG. 6A, the prepared cement mortar is filled in the joints 3b. This filling is performed as shown in FIG.
As shown in the figure, the cement mortar is formed so as to protrude at a height of 5 mm or less from the outer surface of the cement board layer 3 to form a peak portion 3c of the cement mortar.

(6) Embedding glass fiber net Then, as shown in FIG. 6 (b), a tape-shaped glass fiber net 4a is applied to the outside of the crest 3c without wrinkles or floating, and FIG. As shown in c), face down with a trowel.
FIG. 5A illustrates this state. The joint 3b between the cement boards 3a, 3a is reinforced by tensile force by laying down the glass fiber net 4a on the crests 3c in this manner, and cracks are generated in the cement mortar layer 4 along the joints. Can be suppressed.

(7) Cement mortar undercoating Further, as shown in FIG. 5B, cement mortar is applied to the outer surface of the cement board layer 3 using the height of the top of the crest 3c as a ruler. By applying the cement mortar as a ruler of the thickness of the ridges 3c in this manner, it is possible to easily apply the cement mortar with a uniform thickness and to easily manage the coating thickness. .

(8) Overcoating of cement mortar Finally, as shown in FIG. 5 (c), the outer surface of the undercoat layer of the cement mortar is overcoated with cement mortar to complete the cement mortar layer 4. As described above, the thickness of the cement mortar layer 4 can be extremely reduced due to the presence of the cement board layer 3, so that the application work on site is easy and the control of the coating thickness is easy.

(9) Finishing After curing of the cement mortar layer 4, various finishes such as spraying, tile application, stone application, etc. can be applied to the outside of the cement mortar layer 4 in the same manner as in a usual wet exterior base.

3. Others Although the embodiment of the exterior base structure and the exterior base construction method according to the present invention has been described above, the present invention is not limited to these, and should be implemented with various modifications.

[0054]

As described above, the exterior base structure according to the present invention is, as in the conventional wet exterior structure, extremely excellent in design, maintainability, and reproducibility, but as a whole, so-called semi-dry half. Because of the wet structure, even if the thickness of the cement mortar applied on site is small, the fire prevention performance is high, and it is possible to reduce on-site work, shorten the period of work and curing, and homogenize the finish. Further, since the lath net is not used, the problem of rust does not occur, and it is also possible to shorten the entire construction period by preceding only the construction of the cement board layer. Furthermore, since no plywood is used, there is no risk of moisture absorption and corrosion of the outer wall, and cracks are less likely to occur in the cement mortar layer.

Even when a cement board layer is formed by jointing a plurality of cement boards in a plane, the cement mortar is filled in the joints, so that the cement boards are firmly integrated with each other and the joint portion is also formed. It is possible to effectively prevent the cement mortar layer from cracking in the joint pattern of the cement board without reducing the fire protection performance of the outer wall.

Further, since the glass fiber nets are embedded and reinforced on both the front and back surfaces of the cement board, the cement board can be prevented from being cracked or chipped during transportation or on-site processing. Can be finished easily and neatly. In particular, when the ventilation space is formed, dew condensation in the wall can be effectively prevented, and the problem of the cross-sectional defect of the ventilation space does not occur.

On the other hand, according to the exterior base construction method of the present invention, on-site work can be reduced by using the premix mortar, and quality can be easily secured. In addition, even when a cement board layer is formed by jointing a plurality of cement boards in a plane, joints can be reinforced quickly and reliably with a glass fiber net, and the cement mortar application work on site can be performed accurately. It can be performed easily and the coating thickness can be easily managed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of an exterior base structure according to the present invention.

2A is an enlarged cross-sectional view of a vertical joint between cement boards, and FIG. 2B is an enlarged vertical cross-sectional view of the horizontal joint.

FIG. 3 is a diagram illustrating an example of layout of a cement board.

FIG. 4 is a process chart illustrating an embodiment of an exterior base construction method according to the present invention.

FIG. 5 is a process drawing following FIG. 4;

FIG. 6 is a diagram illustrating a joint processing operation.

7A is a partially cutaway perspective view showing a conventional wet exterior structure, and FIG. 7B is a transverse sectional view of the same.

FIG. 8A is a partially cutaway perspective view showing a conventional wet exterior structure, and FIG. 8B is a transverse sectional view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Exterior wall skeleton layer 1a ... Vertical frame 1b ... Plaster board 1c ... Structural plywood 1d ... Glass wool 2 ... Vent layer 2a ... Body edge 2b ... Moisture-permeable waterproof sheet 3 ... Cement board layer 3a ... Cement board 3b ... Joint 3c ... Part 4: Cement mortar layer 4a: Glass fiber net 5: Waterproof paper 6: Lath net 7: Cement mortar 8: Plywood A: Ventilation space S: Finishing layer

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yoshimitsu Ito 1-6-1 Konan, Minato-ku, Tokyo Shinagawa Cristal Square Mitsubishi Rayon Co., Ltd. F-term (reference) 2E001 DB02 DB05 DE01 EA09 FA04 GA10 GA12 GA32 HA01 HA33 LA10 LA16 NA07 NC01 ND12 2E002 EB12 FB05 GA06 MA06 MA27 MA28 MA36

Claims (8)

[Claims] 1. An exterior base structure comprising: a cement board layer supported on the outer side of an outer wall frame; and a cement mortar layer applied to an outer surface of the cement board layer. 2. The cement board according to claim 1, wherein the cement board layer is formed by laying a plurality of cement boards in a plane and filling joints between the cement boards with the cement mortar. Exterior base structure. 3. The exterior base structure according to claim 2, wherein the joint is covered with a glass fiber net from the outside. 4. The exterior base structure according to claim 1, wherein both sides of the cement board layer are reinforced with a glass fiber net. 5. The exterior base structure according to claim 1, wherein irregularities are formed on an outer surface of the cement board layer. 6. The exterior base structure according to any one of claims 1 to 5, wherein a ventilation space is formed between the outer wall frame and the cement board layer. 7. A step of attaching a cement board to the outside of the outer wall skeleton, and applying a cement mortar prepared by adding water or a polymer emulsion to a premix mortar to an outer surface of the cement board. Exterior base construction method characterized by the following. 8. A step of attaching a plurality of cement boards so as to be laid on the outside of the outer wall frame, and forming a ridge bulging at a height of 5 mm or less from the outer surface of the plurality of cement boards. A step of filling a cement mortar prepared by adding water or a polymer emulsion to a mixed mortar into joints between the plurality of cement boards; a step of embedding a glass fiber net in the peak; and a ruler for a top end of the peak And applying the cement mortar to the outer surface of the cement board.