JP7602360B2 - How to repaint exterior walls - Google Patents

Description

This invention relates to a method for repainting exterior walls.

When a house or other building is constructed, the exterior walls are painted. Then, as time passes and the building deteriorates, renovations such as repainting the exterior walls are carried out depending on the degree of deterioration.

When repainting the exterior walls of buildings, it is common to simply apply a new coating over the existing paint film (see, for example, Patent Document 1).

JP 2016-204981 A

In the case of Patent Document 1 mentioned above, repainting is done by applying paint over the existing paint film, but if the condition of the existing paint film is poor, there is a risk that the finish will not be satisfactory even if repainting is done on top of it.

Therefore, the main objective of the present invention is to contribute to improving the above-mentioned problems.

In response to the above problems, the present invention provides:
A method for repainting an exterior wall in which a reinforcing material is attached along a joint between exterior wall materials and an existing coating film is formed on the exterior wall material and the reinforcing material, comprising:
Peel off the existing reinforcing material from the joint portion,
A new reinforcement material is attached to the joint portion from which the existing reinforcement material has been removed,
The method is characterized in that an adjusting coating film of the same type as the existing coating film is formed on the portion where the new reinforcing material is attached, either a soft coating film that has the flexibility to elastically deform in response to the displacement and deformation of the exterior wall material, or a hard coating film that can withstand the displacement and deformation of the exterior wall material.

According to the present invention, the above configuration makes it possible to restore the existing coating on the exterior wall to a good condition by repainting it.

1 is an overall side view of a building in which an exterior wall repainting method according to an embodiment of the present invention is performed. FIG. 2 is a cross-sectional view of an exterior wall on which an existing coating film has been formed. FIG. 2 is a cross-sectional view showing an exterior wall structure that has been subjected to the exterior wall repainting method according to the present embodiment. FIG. 11 is a plan view of an exterior wall showing the existing reinforcement material removal process. FIG. 5 is a perspective view of an exterior wall showing an existing reinforcement material removing step following FIG. 4 . It is a figure of an outer wall which shows the new reinforcement material attaching process. In this, (a) is a perspective view of the outer wall, and (b) is a cross-sectional view of the outer wall. 7A and 7B are views of an exterior wall showing a new reinforcing material attachment step following the step of FIG. 6. In these figures, (a) is a perspective view of the exterior wall, and (b) is a cross-sectional view of the exterior wall. FIG. 2 is a perspective view of a building for explaining the cause of deterioration of the building. 1 is a side view of a building showing the repeated deformation and recovery of an exterior wall material, in which (a) shows the state before deformation or the restored state, and (b) shows the deformed state. This is a side view of a building showing a crack that occurred in a joint in an exterior wall.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
1 to 10 are intended to explain this embodiment.

<Configuration> The configuration of this embodiment is explained below.

For example, when a building 1 such as a house as shown in FIG. 1 is newly constructed, the surface of the exterior wall 2 of the building 1 is painted as shown in the cross-sectional view of FIG. 2.

Then, when the building 1 deteriorates over time after it is newly constructed, the exterior walls 2 are repainted or other renovations are carried out according to the degree of deterioration of the building 1.

Here, the building 1 may be any type of building, such as a detached house or an apartment building. The building 1 may be of any structure, such as wood, concrete, or steel frame construction, but it is preferable that the building 1 be a unit building. A unit building is a building 1 that can be constructed in a short period of time by transporting building units 4 manufactured in advance at a factory to a construction site and assembling them at the construction site. In this embodiment, the building 1 is two stories high, with the building unit 4 on the upper floor stacked on top of the building unit 4 on the lower floor. The building 1 may be a single-story building, or a multi-story building with three or more floors.

The new construction period is when Building 1 was constructed.

The exterior wall 2 is located on the exterior side of the building 1 and is the side (outer surface) of the building 1 that faces the outdoors. The exterior wall 2 has its surface painted to give it an aesthetic look, and the paint protects it from ultraviolet rays and wind and rain.

Deterioration of the building 1 includes, for example, deterioration of the paint (existing paint film 6) due to ultraviolet rays, and cracks (cracks 8) in the paint (existing paint film 6) caused by repeated deformation and recovery of the building 1 due to lateral external forces (lateral forces 7) associated with earthquakes and strong winds.

Repainting refers to repairing the exterior wall 2 of a building 1, on which an existing coating film 6 has been formed, by applying new paint partially or entirely over time. Repainting can also be carried out when the building 1 deteriorates or according to a schedule based on the maintenance plan for the building 1.

In addition to the basic configuration described above, this embodiment can have the following configuration:

(1) The method for repainting exterior walls in this embodiment is as follows:
As shown in Figure 2, a reinforcing material 13 is attached along a joint 12 between exterior wall materials 11, and an existing coating film 6 is formed on the exterior wall material 11 and the reinforcing material 13. The exterior wall 2 is then repainted, for example, as shown in Figure 3 (note that the up-down relationship is reversed between Figures 2 and 3).
In this case, in the exterior wall repainting method of this embodiment, at least
As shown in FIG. 4 and FIG. 5 , a process of removing the existing reinforcement material 13 from the joint portion 12 (existing reinforcement material removal process);
As shown in FIG. 6 and FIG. 7 , a process of attaching a new reinforcing material 14 to the joint portion 12 from which the existing reinforcing material 13 has been removed (a new reinforcing material attachment process);
A process of forming an adjusting coating film 15 (FIG. 3) of the same type as the existing coating film 6 on the portion where the new reinforcing material 14 is attached (adjusting coating film forming process) is carried out.

The exterior wall material 11 here is a construction material that serves as the base for the exterior wall 2 of the building 1. Standard-sized board materials are used for the exterior wall material 11, and it is installed on the building 1 either as is, or after being cut to the required size and shape according to the building 1, or after appropriate processing such as drilling holes for openings such as windows. The exterior wall material 11 that remains at the standard dimensions is installed vertically with its length facing up and down. It is preferable to install the exterior wall material 11 so that it becomes a load-bearing wall for the building 1.

The joints 12 are linear joints (joint lines) formed between the side edges of adjacent exterior wall materials 11, and extend in the vertical direction 16. The joints 12 may be installed on the building 1 with adjacent exterior wall materials 11 directly butted together, or may be installed on the building 1 with a gasket interposed between them.

The location of the joint 12 is a place where cracks (cracks 8) are likely to occur in the existing coating film 6, as shown in Figure 1.

Cracks in such existing coating films 6 occur, for example, due to lateral forces 7 (lateral external forces associated with earthquakes, strong winds, etc.) acting on the building 1, as shown in Figure 8.

That is, as shown in Figures 9(a) and 9(b), the above-mentioned lateral force 7 causes the load-bearing walls (exterior wall materials 11 having surfaces parallel to the lateral force 7) that make up the exterior wall 2 of the building 1 to be displaced or deformed laterally, causing adjacent load-bearing walls to slightly shift or return along the joints 12 (shift 17). As a result of this small shift 17 movement being repeated over a long period of time, the existing reinforcing materials 13 attached to the joints 12 can no longer withstand it, and as shown in Figure 10, a crack 8 extending approximately in the vertical direction 16 along the joints 12 is generated in the existing coating film 6 at the position of the joints 12.

The existing reinforcement material 13 is a reinforcing building material (existing reinforcement material or original reinforcement material) that is attached to the joints 12 of the exterior wall 2 when the building 1 is newly constructed, and connects the sides of adjacent exterior wall materials 11 to reinforce the joints 12. The existing reinforcement material 13 is in the form of a strip or tape, and is attached along the joints 12 of the exterior wall material 11 over the entire area of the joints 12 in the up-down direction 16. For example, existing reinforcement materials 13 have been made of cheesecloth as a base material.

The existing coating film 6 is a film of paint that was applied to the surface of the exterior wall 2 or the existing reinforcement material 13 when the building 1 was newly constructed (the existing coating film or the initial coating film). The existing coating film 6 is formed in a substantially uniform state on the surface of the exterior wall 2. The existing coating film 6 may be of any type.

The new reinforcement material 14 is a building material for reinforcing and restoring function, which is attached to the joints 12 of the exterior wall material 11 after the existing reinforcement material 13 is removed in place of the existing reinforcement material 13, and restores the protective function of the joints 12 (new reinforcement material or renewal reinforcement material). It is preferable to use a strip or tape-shaped material for the new reinforcement material 14 that has the same width and thickness as the existing reinforcement material 13. The new reinforcement material 14 is attached along the entire area of the joints 12 in the vertical direction 16 of the exterior wall material 11. It is preferable to use a new reinforcement material 14 that has the same or higher performance than the existing reinforcement material 13. For the new reinforcement material 14, an elastic joint tape can be used, which releases stress by following deformations such as displacement and dimensional changes of the exterior wall material 11, and further has improved durability against ultraviolet rays and heat. Elastic joint tape is a new material that has been developed in recent years.

The new reinforcement material 14 may be applied only to the existing reinforcement material 13 at the position where the cracked portion 8 actually occurred, or to the existing reinforcement material 13 at the position where the cracked portion 8 actually occurred and at the position where the cracked portion 8 is predicted to occur in the future, or to all the existing reinforcement materials 13.

As shown in Figures 6 and 7, it is preferable to use a new reinforcing material 14 that has a continuous or discontinuous marking extending along the length of the new reinforcing material 14 at the center of the width. The marking can be a colored line, such as a red line 14a, for example, for easy identification. This red line 14a allows the new reinforcing material 14 to be attached in the correct position along the up-down direction 16 without being misaligned in the width direction relative to the joint portion 12. The new reinforcing material 14 may be in the form of a double-sided tape with a release film 14b attached to the back side.

The adjusting coating film 15 is a paint used for partial repainting of the exterior wall 2, and is of the same type as the existing coating film 6. The type of the existing coating film 6 can be identified using data from the time of new construction. If the same type of adjusting coating film 15 as the existing coating film 6 cannot be obtained, an equivalent substitute is used. The adjusting coating film 15 is formed flush with the existing coating film 6 without any steps, so that it blends in with the remaining existing coating film 6. It is preferable to adjust the color of the adjusting coating film 15 to the same color as the current color of the existing coating film 6.

If the existing coating film 6 has an exterior wall pattern, the adjusting coating film 15 is finished to have the same exterior wall pattern as the existing coating film 6. Exterior wall patterns are three-dimensional uneven shapes, and there are a variety of patterns, such as stucco patterns with a stucco finish, sand wall patterns, wavy patterns, citrus peel patterns, and various plastering patterns with trowel marks. By taking the time to create these exterior wall patterns in the adjusting coating film 15, the adjusting coating film 15 becomes an exterior wall pattern-matching paint that matches the exterior wall pattern of the existing coating film 6.

The existing reinforcement removal process is carried out as follows:

First, as shown in Figure 4, a cut line 19 is made in the existing coating film 6 at the joint 12 where the crack 8 has occurred, using a cutting tool 18 such as a utility knife. The cut line 19 may be made perpendicular to the exterior wall 2, but it is preferable to make it at an angle that faces diagonally inward (Figure 2).

Diagonally inward refers to a shape that is inclined in the width direction (horizontal direction) of the exterior wall 2 at the same position in the up-down direction 16, with the direction perpendicular to the exterior wall 2 as the reference, so that the indoor side of the cut line 19 is located near the joint 12 and the outdoor side of the cut line 19 is located farther away from the joint 12. By forming the cut line 19 diagonally inward in this way, the edge of the existing coating film 6 cut by the cut line 19 gradually changes to a tapered shape, which allows the adjustment coating film 15 to blend better with the existing coating film 6.

Two cut lines 19 are formed in the vertical direction 16 roughly along the existing reinforcement 13, on both sides of the existing reinforcement 13 attached to the joint 12 or slightly outside both sides, so that the width is roughly the same as or slightly wider than the width of the existing reinforcement 13.

It is preferable that the cut line 19 is formed along the entire area of the joint 12 of the exterior wall material 11 in the vertical direction 16, along the joint 12 where the crack 8 occurs, rather than being formed partially around the crack 8.

Next, as shown in FIG. 5, the existing reinforcing material 13 and the existing coating film 6 on the inside of the cut line 19 are simultaneously peeled off from the exterior wall 2 along the cut line 19. For at least the portion of the joint portion 12 in the exterior wall 2 where the crack portion 8 has occurred, the existing reinforcing material 13 is peeled off in the entire vertical direction 16 without being left behind.

Furthermore, the existing reinforcement material 13 may be peeled off in the same manner as described above not only in the position where the cracked portion 8 has occurred, but also in the position where the cracked portion 8 is predicted to occur in the future, or even in all existing reinforcement materials 13.

As a result, the peripheral portion of the joint portion 12 at the side edge of the exterior wall material 11, where the existing reinforcing material 13 has been removed, is exposed to the outside over the entire area of the joint portion 12 in the vertical direction 16. Then, the peripheral portion of the joint portion 12 is reset to a state of only the exterior wall material 11.

Then, preferably, the following base preparation is carried out on the surrounding area of the joint 12 of the exterior wall material 11 from which the existing reinforcing material 13 has been removed (base preparation process).

First, thoroughly remove any dust, oil, dirt, etc. adhering to the surface of the exterior wall material 11 that is exposed by removing the existing reinforcing material 13.

If any of the exterior wall materials 11 are loose, the loose parts are repaired by driving more nails into the affected parts at a fine pitch, and an ultraviolet ray deterioration inhibitor is applied to the joints between the exterior wall materials 11 and to the nail heads. Note that if stainless steel nails are used, it is not necessary to apply an ultraviolet ray deterioration inhibitor to the nail heads.

In addition, if there is a gap of, for example, 2 mm or more between the butt joints of the exterior wall materials 11, a filler such as a round rod-shaped highly expanded polyethylene filler is inserted into the gap to fill it.

In addition, a specified paint may be applied evenly to the surface of the exterior wall material 11 as a primer using a painting tool such as a roller, and then allowed to dry thoroughly.

The new reinforcing material attachment process described above is carried out as follows:

As shown in Figure 6, the surface of the new reinforcing material 14 without the release film 14b is attached in the vertical direction 16 along the entire area of the joint 12 of the exterior building material 11, while aligning the red line 14a with the center of the joint 12. At this time, the new reinforcing material 14 is pressed firmly against the surface of the exterior building material 11 using a soft cloth such as a rag to sufficiently bond it to the surface of the exterior building material 11, and then the release film 14b is peeled off from the new reinforcing material 14 as shown in Figure 7.

When doing this, it is important to note that if the new reinforcing material 14 is not pressed firmly enough, it can cause blisters in the adjusting coating film 15 and other parts later on. Be sure to remove the release film 14b when applying the new reinforcing material 14. If the thickness of the new reinforcing material 14 is not set to match the existing coating film 6, taking into account the thickness of the adjusting coating film 15, it can cause poor appearance in the finished product.

The above-mentioned adjustment coating film formation process is carried out as follows.

The same paint as the existing coating film 6 is applied as an adjustment coating film 15 on the new reinforcing material 14, as well as on the tape edges (both side edges) of the new reinforcing material 14 and in the surrounding areas.

The adjustment coating film 15 is applied carefully, particularly to the tape edge of the new reinforcing material 14, to eliminate any steps between the tape edge of the new reinforcing material 14 and the existing coating film 6, resulting in a smooth finish to the adjustment coating film 15.

If the existing coating film 6 has an exterior wall pattern, the same exterior wall pattern is formed on the new reinforcing material 14, and the adjusting coating film 15 is made to match the existing exterior wall pattern. For example, if the existing coating film 6 has a stucco finish, stucco beads are also sprayed onto the adjusting coating film 15 to make the adjusting coating film 15 the same as the stucco finish pattern (stucco-like pattern) of the existing coating film 6. If the existing coating film 6 has a different exterior wall pattern, the adjusting coating film 15 is made to match the exterior wall pattern.

Please note that if the exterior wall patterns of the existing coating film 6 and the adjusting coating film 15 are not matched, the finished appearance will be poor. Matching of the exterior wall patterns should be done in accordance with the specifications of the existing coating film 6 and other specifications for the building 1.

In this way, by carrying out each of the above steps in order, the exterior wall 2 of the building 1 is restored to the same painted condition as when it was newly built. If there are only a few cracks 8 in the existing coating film 6 applied to the exterior wall 2, repainting of the exterior wall 2 may be completed with this partial repair. On the other hand, if there are many cracks 8 in the existing coating film 6 applied to the exterior wall 2 or if the resident requests it, the exterior wall 2 may be repainted further as follows.

(2) As shown in FIG. 3, a new coating film 21 may be formed on the existing coating film 6 and the adjustment coating film 15.

The new coating film 21 here is a film of paint that is applied over the existing coating film 6 to the entire surface of the exterior wall 2 when, for example, the entire building 1 is to be repainted (new coating film). The new coating film 21 is also applied over the adjusting coating film 15. As a result, the new coating film 21 becomes a topcoat.

The new coating film 21 may be a single layer, but it can also be a two-layer coating of an undercoat coating film 22 and a topcoat coating film 23, or a multi-layer coating of three or more layers with an intermediate coating film between the undercoat coating film 22 and the topcoat coating film 23. For the undercoat coating film 22, the topcoat coating film 23, and the intermediate coating film, for example, a urethane-based or silicone-based soft paint can be used. A soft paint is a paint that has the flexibility to elastically deform in response to the displacement and deformation of the exterior wall material 11 due to the lateral force 7 described above.

(3) The new coating film 21 may be a hard coating film 31.

Here, for example, a fluorine-based paint can be used for the hard coating film 31. In the case of multi-layer coating, the hard coating film 31 can be used for at least the top coating film 23. The undercoat coating film 22 and the intermediate coating film can be either a hard coating film 31 or a soft coating film made of a soft paint.

Even if a hard coating film 31 is used for the new coating film 21, the protective function for the joints 12 is restored by the new reinforcing material 14. Also, for example, by using an elastic joint tape with higher performance than the existing reinforcing material 13 for the new reinforcing material 14, the protective function for the joints 12 is strengthened compared to when the building was new, so that the hard coating film 31 can withstand the above-mentioned displacement and deformation of the exterior wall material 11 for a long period of time.

(4) The exterior wall structure formed by the above-mentioned exterior wall repainting method is as follows:
A new reinforcing material 14 is attached along the joints 12 which are the joining points between the exterior wall materials 11 .
The existing coating film 6 remains on the portion of the exterior wall material 11 other than the joint portion 12 .
A control coating 15 of the same type as the existing coating 6 is formed on the portion where the new reinforcing material 14 is attached.

Here, it is necessary to restore the protective function of the joints 12 by carefully removing the existing reinforcing material 13 and replacing it with new reinforcing material 14. It is effective to carry out the above-mentioned base treatment around the joints 12 from which the existing reinforcing material 13 has been removed in order to restore the protective function and perform repainting smoothly.

The new reinforcing material 14 is attached along the joints 12 of the exterior wall material 11 from which the existing reinforcing material 13 has been completely removed, over the entire area of the joints 12 in the vertical direction 16. It is also important that the adjusting coating film 15 has the same exterior wall pattern as the existing coating film 6, so as to blend in, in order to prevent the influence of the existing coating film 6 from appearing. The color and exterior wall pattern of the adjusting coating film 15 are adjusted so as to blend in with the current existing coating film 6.

As a result, the existing coating film 6 remains on the surface of the exterior wall 2 as if it had been there for the same number of years as the building 1, while the adjusting coating film 15 and the new coating film 21 are newly formed on the surface of the exterior wall 2 around the joints 12 as if they had been newly applied during the renovation, so that the coating films with different ages (the existing coating film 6 and the adjusting coating film 15) coexist in a state of being assimilated into the exterior wall 2.

As described above, a new coating film 21 may be formed on the entire surface of the exterior wall 2 on top of the existing coating film 6 and the adjusting coating film 15, depending on the degree of deterioration of the building 1 and the requests of the residents. The new coating film 21 may be a single layer, but may also be a multi-layer coating of two or more layers, with an undercoat coating film 22 and a topcoat coating film 23 superimposed on top of each other.

In addition, a hard coating film 31 may be used for the new coating film 21.

Otherwise, the process can be the same as described above for the exterior wall repainting method.

<Effects> This embodiment provides the following effects:

(Effects 1) In the exterior wall repainting method of this embodiment, the existing reinforcing material 13 is peeled off from the joint area 12, new reinforcing material 14 is attached to the joint area 12 after the existing reinforcing material 13 has been peeled off, and an adjustment coating film 15 of the same type as the existing coating film 6 is formed in the area where the new reinforcing material 14 is attached.

As a result, the area around the joints 12, which are the most susceptible to deterioration of the existing coating film 6, is repaired with new reinforcing material 14, and the new reinforcing material 14 restores the joints 12 to the same protective function as when they were first built. In this case, for example, if a new reinforcing material 14 with higher performance than the existing reinforcing material 13 is used, it will be possible to strengthen the joints 12 by providing them with a protective function that is greater than that of the original.

In addition, by repairing the joints 12 with new reinforcing material 14 and adjusting coating film 15, the paint on the exterior wall 2 is restored to a state in which the adjusting coating film 15 and the existing coating film 6 are integrated, so that the existing coating film 6 remaining on the surface of the exterior wall 2 cannot be distinguished from the adjusting coating film 15 newly applied to the joints 12.

Removing the existing reinforcing material 13 from the joints 12 is a labor-intensive task, and has not been done in the past. However, removing the existing reinforcing material 13 from the joints 12 not only eliminates the adverse effects that would occur after repainting if the existing reinforcing material 13 were left in the joints 12, but is also effective in restoring the protective function of the joints 12 with new reinforcing material 14 and in smoothly repainting the adjusting coating film 15 on the new reinforcing material 14. Therefore, by carrying out the above exterior wall repainting method, the exterior wall 2 is returned (restored) to a state equivalent to that when it was newly built, covered with the existing coating film 6.

(Effect 2) A new coating film 21 may be formed so as to straddle the existing coating film 6 and the adjusting coating film 15 (whose protective function has been restored to the same state as when the building was new and has been assimilated into the existing coating film 6). This allows the existing coating film 6 and adjusting coating film 15 to be completely covered and hidden by the new coating film 21. The new coating film 21 can then be satisfactorily formed over the entire surface of the exterior wall 2 in a state in which it is unlikely to be affected by the existing coating film 6 and adjusting coating film 15.

(Effect 3) Although the hard coating film 31 is a paint that is relatively susceptible to the influence of the base, it may be applied as a new coating film 21 to the exterior wall 2 that has been repaired with the adjusting coating film 15 so that the influence of the existing coating film 6 is less likely to occur. This makes it possible to form the hard coating film 31 on the entire surface of the exterior wall 2 without any problems, even if the hard coating film 31 is used for the new coating film 21.

(Effect 4) The exterior wall structure of this embodiment may be an exterior wall 2 repainted by the exterior wall repainting method described above. In this exterior wall 2, new reinforcing material 14 is attached along the joints 12 between the exterior wall materials 11, the existing coating film 6 remains in the parts of the exterior wall material 11 other than the joints 12, and an adjusting coating film 15 of the same type as the existing coating film 6 is formed in the part where the new reinforcing material 14 is attached. As a result, the protective function of the joints 12 is restored by the new reinforcing material 14, and the adjusting coating film 15 is blended with the existing coating film 6 so that it is indistinguishable from the existing coating film 6, so that the same effect as the exterior wall repainting method described above can be obtained.

REFERENCE SIGNS LIST 1 Building 2 Exterior wall 6 Existing coating film 11 Exterior wall material 12 Joint 13 Existing reinforcing material 14 New reinforcing material 15 Adjustment coating film 21 New coating film 31 Hard coating film

Claims (4)

A method for repainting an exterior wall in which a reinforcing material is attached along a joint between exterior wall materials and an existing coating film is formed on the exterior wall material and the reinforcing material, comprising:
Peel off the existing reinforcing material from the joint portion,
A new reinforcement material is attached to the joint portion from which the existing reinforcement material has been removed,
This method of repainting exterior walls is characterized by forming, on the portion where the new reinforcing material is attached, an adjustment coating of the same type as the existing coating, either a soft coating film that has the flexibility to elastically deform in response to the displacement or deformation of the exterior wall material, or a hard coating film that can withstand the displacement or deformation of the exterior wall material. The method for repainting an exterior wall according to claim 1,
A method for repainting exterior walls, comprising forming a new coating film on the existing coating film and the adjusting coating film. The exterior wall repainting method according to claim 2,
A method for repainting exterior walls, characterized in that the new coating film is a hard coating film. An exterior wall structure subjected to the exterior wall repainting method according to any one of claims 1 to 3,
New reinforcement materials were installed along the joints between the exterior wall materials,
The existing coating film remains in the portion of the exterior wall material other than the joint portion,
An exterior wall structure characterized in that an adjusting coating of the same type as the existing coating is formed in the portion where the new reinforcing material is attached, either a soft coating film that has the flexibility to elastically deform in response to the displacement and deformation of the exterior wall material, or a hard coating film that can withstand the displacement and deformation of the exterior wall material .