Seismic reinforcement methods for wooden houses

Abstract

We provide a seismic reinforcement method for wooden houses that offers high strength and low construction costs. [Solution] This construction method is a seismic reinforcement method for existing wooden houses and comprises a demolition area determination step and a construction step. In the demolition area determination step, the location of embedded objects within the walls of the wooden house is investigated, and the wall 102 in the area where load-bearing walls will be installed and the ceiling 103 extending a predetermined width L (L is, for example, about 300 mm) from the edge of the wall are determined as the demolition area K. In the construction step, the wall 102 and ceiling 103 are demolished based on the demolition area K determined in the demolition area determination step, and structural plywood 21, which is divided into upper and lower sections, is attached to the wall in a true wall style via furring strips 20 without demolishing the floor 101.

Description

Technical Field

[0001] The present invention relates to a seismic reinforcement method for wooden houses, and particularly relates to the current situation survey and wall reinforcement structure in existing wooden houses.

Background Art

[0002] Conventionally, seismic reinforcement of wooden houses has become a social issue. In the earthquake off the coast of Miyagi Prefecture in 1978, many buildings were damaged. In response to this, the Building Standards Law was greatly revised in 1981 (Showa 56), and the seismic performance required for buildings was enhanced. Since then, the seismic performance before the revision of the Building Standards Law in 1981 has been called old seismic resistance, and that after 1981 has been called new seismic resistance. In the Great Hanshin Earthquake in 1995, many old-seismic wooden houses collapsed, resulting in many casualties among the residents. In Kumamoto in 2016, there were also cases where not only old-seismic but also new-seismic wooden houses with an old construction year collapsed. In response to this, the government has, since the Great Hanshin Earthquake, enacted the Seismic Retrofitting Promotion Law to promote the seismic reinforcement of old-seismic wooden houses.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Firstly, in older wooden houses built between 20 and 40 years ago, the client requesting the renovation (such as the homeowner) often does not have the building plans, and it is unclear which walls are load-bearing walls, such as columns and braces. In this case, it is impossible to evaluate the current seismic performance of the building, and it is impossible to determine how much seismic reinforcement is necessary. While the location of columns and braces can be determined by removing the wall framing, it is rarely permitted to remove the wall framing before providing an estimate for seismic reinforcement work.

[0005] Furthermore, when it comes time to carry out seismic reinforcement work, if the plan is to reinforce with bracing or structural plywood, the floor, wall, and ceiling framing must be removed before the bracing can be installed. With conventional methods of seismic reinforcement, the cost of removing and then restoring the floor, wall, and ceiling framing becomes enormous, which is one of the reasons why seismic reinforcement of older wooden houses that do not meet current seismic standards has not progressed.

[0006] Furthermore, when reinforcing with bracing, the strength of a single 45x90 brace as defined by the Building Standards Act is 2.0 for wall strength ratio and 4.0 for double bracing. However, the Ministry of Land, Infrastructure, Transport and Tourism has announced that the Building Standards Act, scheduled for revision in 2025, will have a maximum wall strength ratio of 7.0 for a single wall, meaning that bracing will become a low-strength load-bearing wall. Lower strength of the load-bearing wall being constructed will result in more reinforcement points, leading to increased construction costs.

[0007] This invention aims to solve these conventional problems and provide a seismic reinforcement method for wooden houses that can be installed with high strength and low construction costs. [Means for solving the problem]

[0008] One aspect of the present invention is a seismic reinforcement method for an existing wooden house, comprising: a demolition range determination step of investigating the location of embedded objects within the walls of the wooden house and determining the demolition range as the walls within the area where load-bearing walls will be installed and the ceiling within a predetermined width from the edge of those walls; and a construction step of demolishing the walls and ceiling based on the demolition range determined in the demolition range determination step, and attaching structural plywood, which is divided into upper and lower sections, to the walls using furring strips without demolishing the floor. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a seismic reinforcement method for wooden houses that can be installed with high strength and low construction costs. [Brief explanation of the drawing]

[0010] [Figure 1] This is an explanatory diagram of the survey equipment used in this construction method. [Figure 2] This is an explanatory diagram of another surveying device used in this construction method. [Figure 3] This is an explanatory diagram for the traditional Japanese wall construction method using supporting members. [Figure 4] This is a schematic diagram showing the demolition area per location in this construction method. [Figure 5] This is a diagram showing the configuration of the underfloor installation components used in this construction method. [Figure 6] This is a diagram showing the configuration of another underfloor installation component used in this construction method. [Figure 7] This is a schematic diagram showing the first construction step in this construction method. [Figure 8] This is a schematic diagram showing the second construction step in this construction method. [Figure 9] This is a schematic diagram showing the third construction step in this construction method. [Figure 10] This is a schematic diagram showing the fourth construction step in this construction method. [Figure 11] This is a schematic diagram showing the fifth construction step in this construction method. [Figure 12] This is a schematic diagram showing the sixth construction step in this construction method. [Figure 13] This is a schematic diagram showing the seventh construction step in this construction method. [Figure 14] This diagram illustrates the components that are manufactured in advance at the factory for this construction method. [Figure 15] This diagram illustrates the components that are manufactured in a factory for new construction using this construction method. [Figure 16] This is an explanatory diagram showing the procedure for constructing a new building using the components shown in Figure 15. [Figure 17] This is an explanatory diagram of the components that are manufactured in a factory for seismic reinforcement of old houses in this construction method. [Figure 18] It is an explanatory drawing showing the procedure for constructing an old house using the member of FIG. 17.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are schematic, and the thicknesses and dimensions of each part may be different from the actual ones. Specific thicknesses and dimensions should be determined in consideration of the following description, but the thicknesses and dimensions in the following description are merely examples and can be appropriately changed without departing from the gist of the present invention. Needless to say, there are also parts where the dimensional relationships and ratios are different between the drawings.

[0012] [Overview] Normally, when reinforcing walls with diagonal braces or structural plywood in existing wooden houses, it is necessary to dismantle the floor, walls, and ceiling. According to the seismic reinforcement method for wooden houses (hereinafter referred to as this method) in the embodiments of the present invention, only the ceiling base gypsum board within the range where the face and hands of the worker can reach, for example, about 300 mm, between the wall base gypsum board and the ceiling wall edge is removed, and without dismantling the floor, a shear wall with higher strength than the diagonal brace single wall magnification of 2.0 can be installed at a low construction cost.

[0013] [Seismic Reinforcement Method for Wooden Houses] In this method, when the reform applicant has drawings, the latest inspection confirmation and deterioration degree inspection are carried out to check whether there are any discrepancies between the drawings and the on-site construction, and a seismic diagnosis is performed based on the results. If the score is less than a predetermined value, a reinforcement plan is proposed. On the other hand, when the reform applicant does not have drawings, a seismic diagnosis is performed by measuring the position of the diagonal braces, the presence or absence of foundation steel bars, and the concrete strength of the foundation using the latest inspection equipment. If the score is less than a predetermined value, a reinforcement plan is proposed.

[0014] Figure 1 is an explanatory diagram of the survey equipment 201 used in this construction method. For example, as shown in Figure 1(A), the wall surface may be scanned with a detector 201 that uses electromagnetic waves. This type of detector 201 is generally called a concrete detector. That is, it emits electromagnetic waves from an antenna onto the concrete surface and measures the time it takes for the electromagnetic waves to be reflected back by materials with different electrical properties, such as reinforcing bars or cavities, to determine the location and depth of the object. As a result, as shown in Figure 1(B), if there are embedded objects M such as columns or braces inside the wall, those embedded objects M can be displayed on the screen 202 of the detector 201.

[0015] Figure 2 is an explanatory diagram of another survey device 203 used in this construction method. For example, as shown in Figure 2(A), a thermal camera 203 using infrared light may be used. The thermal camera 203 measures temperature by sensing infrared light emitted by a substance with a sensor. As a result, as shown in Figure 2(B), if there are embedded objects M such as columns 204a or braces 204b inside the wall, their temperature can be visualized and displayed on the screen 204 of the thermal camera 203.

[0016] Based on the information obtained from these survey devices 201 and 203, the location of buried structures M such as columns and braces is determined without demolishing any part of the building during the construction cost estimation stage. The current seismic performance of the building is then evaluated, and the necessity of adding load-bearing walls and where to install them is considered. As a result of this consideration, a construction method was invented that minimizes the demolition area when adding load-bearing walls. Hereinafter, the process of determining the minimum necessary demolition area will be called the "demolition area determination process," and the process of constructing within that demolition area will be called the "construction process." Furthermore, the load-bearing walls to be added during the construction process will not be low-strength braces, but rather high-strength structural plywood newly specified or to be specified in the Ministry of Land, Infrastructure, Transport and Tourism Notification No. 490 of 2018. This structural plywood is of a type called "receiving material true wall specification," and its strength is 1.65 times that of a 45x90 single brace, resulting in a wall strength ratio of 3.3 times. When applied to both sides of the wall, it becomes 6.6 times, which is close to the maximum wall strength ratio of 7.0 for a single wall mentioned earlier. If the load-bearing wall being constructed has high strength, the number of reinforcement points will decrease, resulting in reduced construction costs.

[0017] Figure 3 is an explanatory diagram of the support member true wall specification, where Figure 3(A) is a perspective view and Figure 3(B) is a schematic front view. For explanatory purposes, Figure 3(A) shows a state in which a part of the structural plywood 21 has been cut out, and Figure 3(B) shows a state in which the structural plywood 21 has not been cut out. Also, in the following explanation, the structural plywood 21 may be simply referred to as "plywood". As shown in Figure 3, the method of attaching the structural plywood 21 in the support member true wall specification involves installing support members 14 to which the structural plywood 21 is attached by nailing to the inside of the columns 8a on both sides and the upper and lower horizontal members 9,13, and then attaching the structural plywood 21 in a true wall (where the column surface and the plywood surface are the same). With conventional methods of attachment, the demolition of the floor, walls, and ceiling was necessary. The structural plywood 21 does not need to be attached as a single sheet across the entire surface between the upper and lower horizontal members 9 and 13; it is also permissible to attach it in upper and lower sections using a bracing member 20, which is the same size as the support member 14.

[0018] Figure 4 is a schematic diagram showing the demolition area K per location in this construction method, and shows a front view of the wall 102 inside the existing wooden house. The existing columns 8a and existing corner columns 8a in Figure 4 correspond to the side columns 8a in Figure 3, and the existing intermediate columns 8b in Figure 4 correspond to the intermediate columns 8b in Figure 3, so the same reference numerals will be used for explanation.

[0019] As shown in Figure 4, the investigation using survey equipment 201 and 203 revealed that a brace (not shown) was installed between the existing column 8a and the existing corner column 8a, and it is assumed that the area including this brace was determined as the demolition area K. In this case, the wall gypsum board 10 in the load-bearing wall installation area is removed, and the ceiling gypsum board 11 is removed from the wall edge of the load-bearing wall installation area for a predetermined width L (L is, for example, about 300 mm), and a load-bearing wall of structural plywood 21 is installed on this wall 102. Most of the ceiling 103 is left intact, and the floor 101 is left completely intact. Even with such a minimum demolition area K, this method allows for the installation of a load-bearing wall of structural plywood 21, as described below, thus minimizing the demolition work and the effort required to restore the finishing materials in the demolition area K.

[0020] In other words, in this construction method, pre-fabricated and framed support members 14 are inserted into the walls 102 and ceiling 103 of the demolition area K and nailed to the columns 8a on both sides and the upper and lower horizontal members 9 and 13. At this time, on the lower horizontal member (sill plate) 13 side under the floor, since the floor 101 is not demolished, if the support members 14 are installed on the sill plate 13 first, the structural plywood 21 cannot be nailed to the support members 14. Therefore, an underfloor installation member 60 with the structural plywood 21 nailed to the support members 14 is manufactured in advance, the underfloor installation member 60 is inserted under the floor, and the support member 14 portion of the underfloor installation member 60 is nailed to the sill plate 13 from above. On the upper horizontal member 9 side, since it is possible to reach in with one's head and hands from the partially demolished ceiling 103, it is possible to nail the structural plywood 21 to the support members 14 even if the support members 14 are installed first.

[0021] As described above, this construction method is a seismic reinforcement method for existing wooden houses and has a demolition area determination process and a construction process. In the demolition area determination process, the location of bracing, etc., is investigated using survey equipment 201 and 203 to determine the minimum necessary demolition area K. In the construction process, based on the demolition area K determined in the demolition area determination process, only the wall gypsum board 10 and the ceiling gypsum board 11 within approximately 300 mm of the ceiling wall are removed, and load-bearing walls with a strength higher than a single bracing wall strength ratio of 2.0 are installed at a low construction cost without demolishing the floor 101.

[0022] [Underfloor installation components] Figure 5 is a diagram of the underfloor installation member 60 used in this construction method, with Figure 5(A) being a top view, Figure 5(B) being a front view, and Figure 5(C) being a side view. As shown in Figure 5, the underfloor installation member 60 is a member in which structural plywood 21 is nailed to a support member (true wall plywood support member) 14 that is installed on the foundation 13. The dimensions of the member are merely examples, but the thickness of the structural plywood 21 (plywood thickness) is, for example, 9 mm. To explain using the front view in Figure 5(B), the dimensions of the support member 14 are, for example, 30 mm thick x 90 mm deep, and the height of the structural plywood 21 is, for example, about 390 mm. A pair of support members 14 are nailed to the back of this structural plywood 21. A gap G is provided between this pair of support members 14, and when the underfloor installation member 60 is installed under the floor, the existing studs 8b fit into this gap G.

[0023] Figure 6 shows the configuration of another underfloor installation member 60T used in this construction method, with Figure 6(A) being a top view, Figure 6(B) a front view, and Figure 6(C) a side view. This underfloor installation member 60T is used when the existing structure is a joist construction method with orthogonal joists 15 on the foundation 13. As explained in the front view of Figure 6(B), the bottom of the underfloor installation member 60T is provided with two recesses H extending inwards. When the underfloor installation member 60T is installed under the floor, the orthogonal joists 15 fit into these recesses H. When viewed from the front in Figure 6(B), the size of the recesses H is, for example, about 61 mm vertically and about 46 mm horizontally. Other points are the same as in Figure 5, so a detailed explanation is omitted. Hereafter, when there is no need to distinguish between "60" and "60T", the underfloor installation member will be collectively referred to as "60".

[0024] [Details of the construction process] The construction process for this method will be explained in more detail below. As shown in Figures 7 to 13, the process proceeds in the order of the 1st to 7th construction steps. Figures 7 to 13 schematically depict the area surrounding the demolition area K determined in the demolition area determination step. Since the work is carried out on the demolition area K, the term "demolition area" can also be replaced with "construction area".

[0025] Figure 7 is a schematic diagram showing the first construction process. Figure 7(A) shows the view looking up from the direction of arrow D1 in Figure 7(B). As shown in Figure 7, based on the demolition range K determined in the demolition range determination process, the wall gypsum board 10 is removed only between the ceiling 103 and the floor 101, and the ceiling gypsum board 11 is removed from the wall edge in a predetermined width L (L is, for example, about 300 mm). At that time, only the furring strips at the edge of the ceiling are removed.

[0026] Figure 8 is a schematic diagram showing the second construction process. Figure 8(B) shows the downward view when viewed from the direction of arrow D2 in Figure 8(A). As shown in Figure 8, the surface 12 of the existing studs 8b is cut by the thickness of the plywood (for example, 9 mm) using a circular saw and a multi-cutter. The underfloor installation member 60 is then inserted, and the support member 14 of the underfloor installation member 60 is nailed to the sill plate 13. If there are orthogonal joists 15 on the sill plate 13, the underfloor installation member 60T is installed (see Figure 6). As shown in Figure 8, when the underfloor installation member 60 is installed under the floor, the height position H of the upper end of the underfloor installation member 60 is higher than the floor 101. Since the height of the plywood 21 of the underfloor installation member 60 is, for example, about 390 mm, there is enough space to put your hand in, and it is possible to easily install the underfloor installation member 60.

[0027] Figure 9 is a schematic diagram showing the third construction process. Figure 9(A) shows the view looking up from the direction of arrow D3 in Figure 9(B). As shown in Figure 9, for example, support members 14 measuring 30 mm x 90 mm are installed in the order S1 → S2 → S3 → S4. The order of S1 and S2 can be reversed, and the order of S3 and S4 can also be reversed.

[0028] Figure 10 is a schematic diagram showing the fourth construction step. As shown in Figure 10(A), column head and column base fittings 18 are installed at the column head T and column base B. As shown in Figure 10(B), a type of column head and column base fitting 18 that can be installed on top of a frame material (supporting material) 19 with a thickness of 30 mm or more may be used. Since the height of the plywood 21 of the underfloor installation member 60 is, for example, about 390 mm, there is enough space to reach in even when using an impact driver to fasten screws, making it easy to install the column head and column base fittings 18.

[0029] Figure 11 is a schematic diagram showing the fifth construction step. As shown in Figure 11, furring strips 20 (for example, 45 mm x 90 mm) are installed on the upper end of the plywood 21 of the underfloor installation member 60. The furring strips 20 are members that are installed on the back of the joint in the height direction when joining structural plywood 21.

[0030] Figure 12 is a schematic diagram showing the sixth construction process. Figure 12(A) shows the view looking up from the direction of arrow D4 in Figure 12(B). As shown in Figure 12, a 9 mm thick structural plywood 21 is divided into upper and lower sections and glued together in the middle via a furring strip 20. Here, of the upper and lower sections of the structural plywood 21, the section glued to the upper part will be called "upper plywood 21A," and the section glued to the lower part will be called "lower plywood 21B." The upper plywood 21A is inserted into the ceiling space from the side and secured to the furring strip 20, and the lower plywood 21B (the plywood 21 that constitutes the underfloor installation member 60) is also secured to the furring strip 20, and the outer perimeter and studs 22 of each plywood 21 are nailed in place. The nail pitch on the outer perimeter is, for example, about 75 mm, and the nail pitch on the studs 22 is, for example, about 150 mm.

[0031] Figure 13 is a schematic diagram showing the seventh construction step. Figure 13(A) shows the view looking up from the direction of arrow D5 in Figure 13(B). As shown in Figure 13, the construction step is completed when the gypsum board 23 for wallpapering is attached in a large wall between the floor 101 and the ceiling 103.

[0032] As described above, this construction method allows for the removal of only the wall gypsum board 10 and the ceiling gypsum board 11 within the range where a worker's face and hands can reach, without dismantling the floor 101, and enables the installation of load-bearing walls with a strength higher than a single bracing wall strength rating of 2.0 at a low construction cost. Since the structural plywood 21 needs to be attached to the entire surface between the upper and lower horizontal members 9 and 13, if the ceiling 103 remains, it would be impossible to drive nails into the ceiling space when attaching the structural plywood 21. In this construction method, since the ceiling gypsum board 11 at the ceiling wall edge (for example, about 300 mm) is removed, it is possible to stick one's head in and drive nails with a nail gun. Also, if the floor 101 remains, it would be impossible to install the support member 14 on the base 13 and drive nails into the plywood 21 from the front. In this construction method, the underfloor installation member 60, which has plywood 21 nailed to the support member 14, is manufactured in advance. Therefore, the underfloor installation member 60 can be inserted under the floor, and nails can be driven into the foundation 13 from above using a nail gun. If even a part of the floor 101 is demolished, the entire flooring usually has to be replaced, which is incomparably more expensive than demolishing the walls 102 or ceiling 103. With this construction method, it is possible to avoid demolishing the floor 101, thus significantly reducing construction costs.

[0033] In the above explanation, the lower plywood 21B (underfloor installation member 60) is installed first, followed by the upper plywood 21A. However, the order in which the upper plywood 21A is installed first, followed by the lower plywood 21B, is also acceptable. Any construction method in which the structural plywood 21, which is divided into upper and lower sections (in other words, structural plywood 21 that is not a single piece), is attached via the furring strips 20 is acceptable.

[0034] [Factory-made components] Figure 14 is an explanatory diagram of the components that are manufactured in advance at the factory in this construction method. Figure 14(A) shows a support unit, Figure 14(B) shows four insulation materials 70, and Figure 14(C) shows one structural plywood 21 (9 mm thick). The support unit in Figure 14(A) includes a support frame 14, a furring strip 20, an underfloor installation member 60, and an underfloor installation member 60T. The support frame 14 is a framed support member 14, so it is denoted by the symbol 14. The underfloor installation member 60 is used when there are no right-angle joists 15, and the underfloor installation member 60T is used when there are right-angle joists 15. The dimensions of each of these components can be adjusted as appropriate to match the demolition area K, etc.

[0035] In this way, the components used in the construction process are unitized in the factory, and only installation is required on-site. This allows for a smoother construction process, improving the construction accuracy of load-bearing walls, a crucial component of wooden houses, and further reducing construction costs. Furthermore, by unitizing the components in the factory, it becomes possible to incorporate high-performance insulation material 70 into the units. In addition, if the support frame 14 is manufactured in the factory, variations for new construction and seismic reinforcement of old houses can be considered, as explained below.

[0036] [For new construction] Figure 15 is an explanatory diagram of components manufactured in a factory for new construction. Figure 15(A) shows the support member, stud, and plywood unit, Figure 15(B) shows two insulation materials 70, and Figure 15(C) shows one structural plywood sheet 21 (9 mm thick). As shown in Figure 15(A), the structural plywood sheet 21 (9 mm thick) is attached in advance to the opposite side of the support member 14 and stud 14b.

[0037] [Construction Procedure for New Buildings] Figure 16 is an explanatory diagram showing the procedure for constructing a new building using the components shown in Figure 15. First, as shown in Figure 16(A), the units of Figure 15(A) are nailed onto the upper horizontal member 9 and the lower rigid floor 24. Two nails are driven diagonally into the ends of the studs 14b under the upper and lower horizontal members 9 and 13. Next, column head and column base hardware (not shown) is installed at the column heads and column bases. Then, as shown in Figure 16(B), the insulation material 70 of Figure 15(B) is installed. Finally, as shown in Figure 16(C), the front side of the structural plywood 21 of Figure 15(C) is nailed to the support member 14 and the studs 14b.

[0038] [For earthquake-resistant reinforcement of old houses] Figure 17 is an explanatory diagram of the components manufactured in a factory for seismic reinforcement of old houses. Figure 17(A) shows the support members, studs, and plywood unit, Figure 17(B) shows four insulation materials 70, and Figure 17(C) shows two structural plywood sheets 21 (9 mm thick). The difference from new construction is that the lintel (described later) is taken into consideration. As shown in Figure 17(A), the support members 14 are nailed to the ends of each piece, and the support members 14 are also nailed to the studs 14b. Structural plywood sheets 21 (9 mm thick) are attached in advance to the opposite sides of the support members 14 and studs 14b.

[0039] [Construction Procedure for Seismic Reinforcement of Old Houses] Figure 18 is an explanatory diagram showing the procedure for constructing a traditional Japanese house using the components shown in Figure 17. In the traditional house, a lintel 25 runs between the upper horizontal member 9 and the lower horizontal member 13. Therefore, as shown in Figure 18(A), the units in Figure 17(A) are nailed to the upper and lower horizontal members 9 and 13 and the lintel 25. Two nails are driven diagonally into the ends of the studs 14b below the upper and lower horizontal members 9 and 13. Next, column head and column base hardware (not shown) is installed at the column head and column base. Then, as shown in Figure 18(B), the insulation material 70 in Figure 17(B) is installed. Finally, as shown in Figure 18(C), the front side of the structural plywood 21 in Figure 17(C) is nailed to the support member 14 and the studs 14b. If the finish is a traditional Japanese wall with plaster, a base treatment material is applied before construction. If the finish is a traditional Japanese wall with wallpaper, gypsum board is applied in layers.

[0040] [Features and effects of this construction method] As described above, this construction method is a seismic reinforcement method for existing wooden houses and comprises a demolition area determination process and a construction process. In the demolition area determination process, the location of embedded objects M within the walls of the wooden house is investigated, and the demolition area K is determined to be the wall 102 in the area where load-bearing walls will be installed and the ceiling 103 extending a predetermined width L (L is the area where a worker's face and hands can fit, for example, about 300 mm) from the edge of the wall. In the construction process, the wall 102 and ceiling 103 are demolished based on the demolition area K determined in the demolition area determination process, and structural plywood 21 (structural plywood 21 that is not a single piece) divided into upper and lower sections is attached to the wall in a true wall manner via furring strips 20. This makes it possible to provide a seismic reinforcement method for wooden houses that minimizes the demolition area K and can be installed with high strength and low construction costs.

[0041] In the construction process, it is desirable to insert the underfloor installation member 60, which has the support members 14 pre-nailed to the structural plywood 21, into the underfloor space from the demolition site, and then nail the support members 14 of the underfloor installation member 60 to the lower horizontal members 13 in the underfloor space from above. This allows the important components used on the lower horizontal members 13 side to be unitized in the factory, and only installation is required on site. As a result, it is possible to improve the construction accuracy of the important components used on the lower horizontal members 13 side and further reduce construction costs.

[0042] Furthermore, when the underfloor mounting member 60 is installed under the floor, it is desirable that the height position H of the upper end of the underfloor mounting member 60 be higher than the floor 101. This allows nails to be driven from the front into all necessary locations without having to dismantle the floor 101.

[0043] Furthermore, during the construction process, it is desirable to insert the pre-framed support members 14 from the demolition site of the ceiling 103, install the support members 14 onto the upper horizontal members 9, and then nail the structural plywood 21 to the support members 14. This allows the important components used on the upper horizontal members 9 side to be unitized in the factory, requiring only installation on site. As a result, it becomes possible to improve the construction accuracy of the important components used on the upper horizontal members 9 side and further reduce construction costs.

[0044] Furthermore, in the demolition area determination process, it is desirable to investigate the location of buried objects M using an electromagnetic wave detector 201 or an infrared thermal camera 203, and to determine the area including the bracing as the demolition area K. This makes it possible to determine the location of buried objects M without demolishing any part of the building at the construction cost estimation stage, and to accurately determine the minimum necessary demolition area K.

[0045] [Explanation in comparison with prior art documents] Prior art documents concerning seismic reinforcement of wooden houses include the aforementioned Patent Documents 1 and 2, but these have not yet solved the problems of the conventional methods. Specifically, in Patent Document 1, load-bearing walls are installed only in the space between the floor and ceiling, but the strength of these load-bearing walls is unknown, and it is clear that they are not structural plywood as specified in Ministry of Land, Infrastructure, Transport and Tourism Notification No. 490 of 2018. Furthermore, there are openings above and below these load-bearing walls, which clearly results in low strength, and it is unclear whether the increased number of installation locations will reduce construction costs. Patent Document 2 is basically the same. This method has clear advantages compared to these prior art documents. Considering that seismic reinforcement of wooden houses has become a social issue, this method can be said to be an invention of extremely practical value. [Explanation of Symbols]

[0046] 9 Upper horizontal members 10. Plasterboard walls 11. Ceiling plasterboard 13 Lower horizontal members (foundation) 14 Supporting members, supporting member frames 21 Structural plywood 60 Underfloor installation components 60T Underfloor Installation Components 101 beds 102 Wall 103 Ceiling 201 Detector (Inspection Equipment) 203 Thermal camera (surveillance equipment) H Height position of the upper end of the underfloor installation component K Demolition area L Specified width (ceiling width) M Buried object

Claims

1. This is a seismic reinforcement method for existing wooden houses. The demolition area determination process involves investigating the location of embedded objects within the walls of the aforementioned wooden house, and determining the demolition area to be the walls in the area where load-bearing walls will be installed, and the ceiling within a predetermined width from the edge of those walls, Based on the demolition area determined in the demolition area determination step, the walls and ceiling are demolished, and the floor is not demolished, and structural plywood divided into upper and lower sections is attached to the wall using furring strips in a true wall configuration. A seismic reinforcement method for wooden houses characterized by having [a certain feature].

2. The seismic reinforcement method for a wooden house according to claim 1, wherein in the construction process, a floor-mounted member with support members nailed to structural plywood in advance is inserted into the floor from the demolition site, and the support member portion of the floor-mounted member is nailed from above to the lower horizontal member in the floor.

3. The seismic reinforcement method for a wooden house according to claim 2, wherein when the underfloor installation member is installed under the floor, the height of the upper end of the underfloor installation member is higher than the floor.

4. The seismic reinforcement method for a wooden house according to claim 1, wherein in the construction process, a pre-framed support member is inserted from the demolition site of the ceiling, the support member is installed on the upper horizontal member, and structural plywood is nailed to the support member.

5. The seismic reinforcement method for a wooden house according to claim 1, wherein in the step of determining the demolition area, the location of the buried object is investigated using a detector that uses electromagnetic waves or a thermal camera that uses infrared rays, and the area including the bracing is determined as the demolition area.

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