Wooden sound-insulating floor

Abstract

To provide a wooden sound insulation floor that can further minimize whole structural floor unit area mass than a case in which a material with greater specific gravity than cross laminated timber is used and that can reduce a heavy floor impact sound without using a material with poor workability compared to lumber.SOLUTION: A wooden sound insulation floor 100 comprises a sound insulation structural floor 10 that is fixed to a building skeleton 1 and extends horizontally, a weight double floor 20 that is supported on a top surface of the sound insulation structural floor and extends horizontally, and a suspended ceiling 30 that is independently suspended from the skeleton. The sound insulation structural floor 10 is composed of timber or a wooden material. In addition, a secondary natural frequency of a two mass point system consisting of the weight double floor 20 and the sound insulation structural floor 10 is set lower than an evaluating frequency of heavy floor impact sound cutoff performance. The sound insulation structural floor 10 has multiple small beams 12 where both ends are fixed to the building skeleton and that extend horizontally, and multiple small beam reinforcements 14 that are orthogonal to the small beams and extend horizontally and where both ends are fixed to the small beams. Unit area mass of the sound insulation structural floor 10 is set to be larger than or equal to twice and be smaller than or equal to two and a half times of the weight double floor 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wooden soundproof floor having a double floor and a suspended ceiling and reducing impact sound of a heavy floor.

Background Art

[0002] In recent years, as a floor structure of buildings such as wooden houses, a wooden soundproof floor that satisfies the impact sound insulation performance of a heavy floor and the impact sound insulation performance of a lightweight floor according to JIS A 1418 has been demanded. "Impact sound of a heavy floor" means a dull and low sound that is largely transmitted to the lower floor, such as "thud" or "clang", when a child jumps or moves a chair. Also, "impact sound of a lightweight floor" means a relatively light and high-pitched sound, such as "thunk" when dropping a spoon on the floor or "pat-pat" when walking in slippers.

[0003] Among these, the impact sound of a lightweight floor can be relatively easily reduced by the material on the surface of the floor material (for example, carpet). On the other hand, it is difficult to reduce the impact sound of a heavy floor only by the material on the surface of the floor material. Therefore, in order to reduce the impact sound of a heavy floor, for example, Patent Document 1 is disclosed.

[0004] The "floor structure" of Patent Document 1 includes a floor main body layer formed by arranging a plurality of floor materials (CLT floor materials) formed of CLT (cross-laminated timber), and a plurality of plate materials having a specific gravity greater than that of the floor material (CLT floor material) on the floor main body layer. It is provided with an impact sound reduction layer of a heavy floor formed by arranging them. "Plate material having a specific gravity greater than that of the floor material" is, for example, an ALC board (specific gravity 0.6 ton / m 3 ), a steel plate (specific gravity 7.85 ton / m 3 ), a precast concrete plate (specific gravity 2.85 ton / m 3 ). In addition, the double floor using this floor structure is provided with a surface layer made of plywood on the impact sound reduction layer of a heavy floor, and support legs are arranged thereon for construction.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the "floor structure" of Patent Document 1, a structural floor (weight floor impact sound reduction layer) that supports a double floor is formed by arranging orthogonally laminated boards, and a board material having a specific gravity greater than that of the orthogonally laminated boards is arranged thereon. However, the "floor structure" of Patent Document 1 had the following problems.

[0007] (1) The "board material having a specific gravity greater than that of the orthogonally laminated boards" is, for example, an ALC board (specific gravity 0.6 ton / m 3 ), an iron plate (specific gravity 7.85 ton / m 3 ), or a precast concrete plate (specific gravity 2.85 ton / m 3 ), so the mass per unit area is large. For example, when the orthogonally laminated board has a thickness of 210 mm (mass per unit area 94.5 kg / m 2 ), the ALC board has a thickness of 100 mm (mass per unit area 60 kg / m 2 ), and the plywood has a thickness of 12.5 mm (mass per unit area 7.5 kg / m 2 ), the mass per unit area of the structural floor is about 162 kg / m 2 . Also, when the board material is an iron plate or a precast concrete plate, the mass per unit area of the structural floor becomes even larger. (2) The "floor structure" of Patent Document 1 is, for example, a flat plate with an overall thickness of 310 mm. However, when constructing the floor of a large room, a support beam (for example, a joist) is required in the middle. Therefore, the mass per unit area of the entire structural floor becomes even larger. (3) Since materials with poor workability such as ALC boards, iron plates, and precast concrete plates are used as compared with wood, it is difficult to process according to the on-site dimensions, and the work efficiency is poor.

[0008] The present invention was devised to solve the above-described problems. That is, an object of the present invention is to provide a wooden soundproof floor that can reduce the mass per unit area of the entire structural floor compared to the case of using a material having a specific gravity greater than that of an orthogonal laminated board, and can reduce the impact sound of a heavy floor without using a material having poor workability compared to wood.

Means for Solving the Problems

[0009] According to the present invention, there is provided a wooden soundproof floor including a soundproof structural floor fixed to a building frame and extending horizontally, a heavy double floor supported on the upper surface of the soundproof structural floor and extending horizontally, and a suspended ceiling suspended independently from the frame and extending horizontally, wherein the soundproof structural floor is made of wood or a woody material, and the second natural frequency of the two-mass system composed of the heavy double floor and the soundproof structural floor is set lower than the evaluation frequency of the heavy floor impact sound insulation performance.

Effects of the Invention

[0010] According to the configuration of the present invention described above, since the soundproof structural floor is made of wood or a woody material and does not use a material having a specific gravity greater than that of an orthogonal laminated board (such as an ALC board, an iron plate, a precast concrete board, etc.), the mass per unit area of the entire soundproof structural floor can be reduced. In addition, since the second natural frequency of the two-mass system composed of the heavy double floor and the soundproof structural floor is set lower than the evaluation frequency of the heavy floor impact sound insulation performance, the heavy floor impact sound can be reduced without using a material having poor workability compared to wood.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0012] Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings. In each figure, the same reference numerals are given to the common parts, and duplicate explanations are omitted.

[0013] FIG. 1 is a side sectional view of a wooden sound insulation floor 100 showing an embodiment of the present invention. In this figure, the wooden sound insulation floor 100 according to the present invention includes a sound insulation structure floor 10, a weight double floor 20, and a suspended ceiling 30.

[0014] The sound insulation structure floor 10 is fixed to the building body 1 (see FIG. 2) and extends horizontally. The building is preferably a wooden building, but may also be a concrete building. The body 1 is preferably a horizontal beam (main beam) of a wooden building. The weight double floor 20 is supported on the upper surface of the sound insulation structure floor 10 and extends horizontally. The suspended ceiling 30 is suspended independently from the building body 1 and extends horizontally.

[0015] FIG. 2 is a plan view of the sound insulation structure floor 10 in FIG. 1, and FIG. 3 is a sectional view taken along line A - A and line B - B in FIG. 2. In FIGS. 2 and 3, the weight double floor 20 and the suspended ceiling 30 are omitted. Also, FIG. 2 is the sound insulation structure floor 10 configured for testing in a laboratory. In FIG. 2, the sound insulation structure floor 10 has a width of 3 m, a length of 4 m, and an area of 12 m 2 Of course, the present invention is not limited to this dimension or area.

[0016] The sound insulation structure floor 10 of the present invention is made of wood or wood-based materials. "Wood" means a solid wood material obtained by directly cutting out square timbers or boards of necessary dimensions from a single log. Also, "wood-based material" means a material obtained by decomposing raw wood into elements (components) of various sizes and then reconstituting them. Glulam, structural plywood, particle board, etc. are wood-based materials.

[0017] In FIGS. 1 to 3, the sound insulation structure floor 10 of the present invention has a plurality of small beams 12 and a plurality of small beam reinforcement members 14.

[0018] In FIG. 2, the small beam support member 11 is fixed to the building frame 1 (for example, a large beam). Both ends of the plurality of small beams 12 are fixed to the building frame 1 via the small beam support member 11 and extend horizontally. Note that the small beam 12 adjacent to the frame 1 may be fixed to the frame 1. Also, the joint between the small beam 12 and the small beam support member 11 is firmly connected, for example, by "half-lap joint". Note that an adhesive or a connecting fitting may be used at the joint. In this example, the small beam 12 is made of wood with a width of 150 mm and a height of 330 mm. Also, the center-to-center distance of the plurality of small beams 12 is set to 317 to 455 mm.

[0019] The plurality of small beam reinforcement members 14 extend horizontally perpendicular to the small beams 12, and both ends are fixed to the small beams 12. In this example, the small beam reinforcement member 14 is made of wood with a width of 105 mm and a height of 105 mm. Also, the center-to-center distance of the plurality of small beam reinforcement members 14 is set to be equal to or less than the center-to-center distance of the adjacent small beams 12. In this example, the center-to-center distance of the small beam reinforcement members 14 is 307 to 455 mm.

[0020] Also, the total cross-sectional area of the plurality (8 in this example) of small beam reinforcement members 14 connecting a pair of small beams 12 is set to be 1.5 times or more and 2.5 times or less (1.78 times in this example) the cross-sectional area of a single small beam 12 (495 cm 2 ) Also, the joint between the small beam reinforcement member 14 and the small beam 12 is firmly connected, for example, by "scarf joint". Note that an adhesive or a connecting fitting may be used at the joint.

[0021] In FIG. 1, the sound insulation structural floor 10 further has an upper surface structural floor 16 fixed to the upper surface of the joist 12. In this example, the upper surface structural floor 16 is laminated with a structural plywood 17a, hard gypsum boards 18a and 18b, and a plywood 17b in this order from the lower layer. Also, the mass per unit area of the hard gypsum boards 18a and 18b is set to be more than half of that of the upper surface structural floor 16. Note that the hard gypsum boards 18a and 18b may be reinforced gypsum boards. With the above-described configuration, it is possible to reduce the lightweight floor impact sound and the heavyweight floor impact sound generated by the double-weight floor 20.

[0022] Also, the upper surface structural floor 16 is firmly fixed to the upper surface of the joist 12, for example, by screws. Note that the structural plywood 17a, the hard gypsum boards 18a and 18b, and the plywood 17b may be simply laminated or the joints may be adhered as long as they move (vibrate) integrally.

[0023] In FIG. 1, the upper surface of the joist reinforcement 14 is lower than the lower surface of the upper surface structural floor 16, and there is a gap therebetween. This gap is set so that the vibration of the upper surface structural floor 16 is not directly transmitted to the joist reinforcement 14. The size of the gap is, for example, 5 to 10 mm. With this configuration, it is possible to prevent the transmission of vibration in the 63 Hz band corresponding to the evaluation frequency of the heavyweight floor impact sound blocking performance from the upper surface structural floor 16 to the joist reinforcement 14, and to prevent the independent vibration of the joist reinforcement 14. Note that this configuration is not essential, and the gap with the upper surface structural floor 16 may be reduced, or the upper surface height of the joist reinforcement 14 may be made to coincide with the upper surface height of the joist 12, and the function of a "floor sill" may be used in combination with the joist reinforcement 14.

[0024] In FIG. 1, the double-weight floor 20 has a plurality of support legs 22 supported on the upper surface (plywood 17b) of the sound insulation structural floor 10. The support legs 22 are composed of, for example, a combination of vibration-proof rubber, metal bolts, and panel receivers.

[0025] The weighted double floor 20 further has a particle board 24, asphalt-based vibration damping materials 25a and 25b, a plywood board 26, and a flooring 27, which are laminated in order from the lower layer on the upper surface of the support legs 22. Note that the particle board 24, the asphalt-based vibration damping materials 25a and 25b, the plywood board 26, and the flooring 27 may be simply laminated or adhered as long as they move (vibrate) integrally. With the above-described configuration, it is possible to reduce the lightweight floor impact sound and the weighted floor impact sound generated in the weighted double floor 20.

[0026] In the present invention, the secondary natural frequency of the two-mass system composed of the above-described weighted double floor 20 and the sound insulation structural floor 1 is set lower than the evaluation frequency of the weighted floor impact sound blocking performance. The evaluation frequency of the weighted floor impact sound blocking performance is in the octave band 63 Hz band to 500 Hz band, and specifically means the range of 45 Hz to 710 Hz. In the present invention, the weighted double floor 20 includes asphalt-based vibration damping materials 25a and 25b, and its natural frequency is set lower than the evaluation frequency (63 Hz band).

[0027] In FIG. 1, the suspended ceiling 30 has a plurality of suspension beams 32, a plurality of suspension hardware 34, a ceiling board 36, and glass wool 38.

[0028] The plurality of suspension beams 32 extend horizontally with both ends fixed to the building body 1 between the plurality of joists 12. The suspension beam 32 is preferably fixed directly to the building body 1 (for example, a large beam) of the building, but may be fixed to the building body 1 via the joist support member 11. Further, the suspension beam 32 is located away from the joist 12 and the joist reinforcement 14, and is set so that the vibration of the joist 12 and the joist reinforcement 14 is not directly transmitted. In this example, the suspension beam 32 is made of wood with a width of 38 mm and a height of 140 mm. The center-to-center distance of the plurality of suspension beams 32 is set to 317 to 455 mm between the joists 12.

[0029] A plurality of hanging weights 34 are installed at intervals along the length direction of the hanging beam 32, with their upper ends fixed to the hanging beam 32 and their lower ends fixed to the ceiling board 36. The ceiling board 36 has its upper surface fixed to the hanging weights 34 and extends horizontally. In this example, the ceiling board 36 is composed of two laminated reinforced gypsum boards 37. It should be noted that the present invention is not limited to this configuration of the ceiling board 36. The glass wool 38 is laid without gaps between the upper surface of the ceiling board 36 and the hanging beam 32.

[0030] With the above-described configuration, the suspended ceiling 30 is not directly connected to the sound insulation structural floor 10, but is independently suspended and extends horizontally separately from the building frame 1, so that it can block the lightweight floor impact sound and heavyweight floor impact sound generated above.

[0031] Table 1 is a table showing the thickness and mass per unit area of the above-described heavyweight double floor 20. Table 2 is a table showing the thickness and mass per unit area of the above-described sound insulation structural floor 10. In FIG. 2, the core-to-core distance of the plurality of small beams 12 is set to 317 to 455 mm, and the core-to-core distance of the plurality of small beam reinforcements 14 is set to 307 to 455 mm. Table 2 shows the portions where the core-to-core distance is 455 mm respectively.

[0032]

Table 1

[0033]

Table 2

[0034] In Table 1, the mass per unit area of the heavyweight double floor 20 is about 65 kg / m 2 is. Also, the mass per unit area of the asphalt-based vibration damping materials 25a and 25b of the heavyweight double floor 20 is about 36 kg / m 2 and is set to more than half (about 55% in this example) of the heavyweight double floor 20.

[0035] In addition, in Table 2, the mass per unit area of the joist 12 is about 65 kg / m 2 and is set to be equal to or more than (equal in this example) that of the weighted double floor 20. In addition, in Table 2, the mass per unit area of the hard gypsum boards 18a and 18b is about 36 kg / m 2 and is set to be more than half (about 62% in this example) of that of the upper surface structural floor 16 (about 58 kg / m 2 ).

[0036] Furthermore, in Table 2, the mass per unit area of the sound insulation structural floor 10 is about 133 kg / m 2 and is about 2.0 times that of the weighted double floor 20. With the above-described configuration, as will be described later, the standard of LH-45 for the weighted floor impact sound can be satisfied. In addition, in the example of Patent Document 1, the mass per unit area of the structural floor is about 162 kg / m 2 However, in the present invention, since materials having a specific gravity larger than that of the orthogonal laminated board (such as ALC boards, iron plates, precast concrete plates, etc.) are not used, the mass per unit area of the sound insulation structural floor 10 can be reduced.

[0037] In the example of FIG. 2, the distance between the cores of the joists 12 can be easily set to 303 mm. In this case, the mass per unit area of the sound insulation structural floor 10 is about 163 kg / m 2 and is about 2.51 times that of the weighted double floor 20. In this case, as will be described later, the standard of LH-45 for the weighted floor impact sound can be further satisfied. In addition, as described above, in the "floor structure" of Patent Document 1, when constructing the floor of a large room, an intermediate support beam (for example, a joist) is required. Therefore, the mass per unit area of the entire structural floor is actually larger than about 162 kg / m 2 in the example of Patent Document 1. Therefore, even when the mass per unit area of the sound insulation structural floor 10 is about 2.5 times that of the weighted double floor 20, the mass per unit area of the sound insulation structural floor 10 can be reduced as compared with Patent Document 1.

[0038] Therefore, the mass per unit area of the sound insulation structure floor 10 is preferably set to be not less than 2 times and not more than 2.5 times that of the weight double floor 20.

[0039] FIG. 4 is a side sectional view of a comparative sound insulation floor 50 of a comparative example. In this figure, the comparative sound insulation floor 50 includes a comparative structure floor 60, a weight double floor 20, and a suspended ceiling 30. The weight double floor 20 and the suspended ceiling 30 are substantially the same as those of the wooden sound insulation floor 100 (FIG. 1) of the present invention.

[0040] The comparative structure floor 60 has a plurality of comparative small beams 62 and a plurality of floor receiving timbers 64. In this example, the plurality of comparative small beams 62 are made of wood with a width of 180 mm and a height of 200 mm. The center-to-center distance of the plurality of comparative small beams 62 is set to 540 mm. In this example, the plurality of floor receiving timbers 64 are made of wood with a width of 45 mm and a height of 45 mm. The center-to-center distance of the plurality of floor receiving timbers 64 is set to 910 mm. Other configurations are substantially the same as those of the wooden sound insulation floor 100 (FIG. 1) of the present invention. In practice, the surface material configuration is slightly different, and the mass per unit area is about 6 kg / m 2 It is lightweight.

[0041] With the above-described configuration, the mass per unit area of the weight double floor 20 of the comparative sound insulation floor 50 is about 65 kg / m, which is the same as in Table 1. 2 It is. Also, the mass per unit area of the comparative structure floor 60 is about 92 kg / m 2 and is about 1.4 times that of the weight double floor 20.

[0042] FIG. 5 is a diagram showing the test results of the weight floor impact sound insulation performance in a testing institution. This test was carried out based on JIS A 1418-2:2019, and a tire having impact force characteristics (1) was used as the impact source. In this figure, the horizontal axis represents the center frequency of the octave band, and the vertical axis represents the weight floor impact sound level. Also, the curves indicated by the five thin lines in the figure show the reference curves of L-35, L-40, L-45, L-50, and L-55 in order from the bottom. Furthermore, the circles and thick solid lines in the figure represent the test results of the sound insulation structural floor 10 described above, and the squares and thick dashed lines in the figure represent the test results of the comparative structural floor 60 described above.

[0043] From the test results in Fig. 5, it can be seen that the weight floor impact sound level of the sound insulation structural floor 10 described above is substantially below the reference curve of L-45 and meets the LH-45 standard for weight floor impact sound. Also, in Fig. 5, it can be seen that the weight floor impact sound level of the comparative structural floor 60 described above meets the LH-50 standard for weight floor impact sound but does not meet the LH-45 standard, showing relatively low performance.

[0044] Fig. 6 is a diagram showing a two-mass system model and its analysis results. In this figure, (A) is the two-mass system model, (B) is the analysis result of the comparative structural floor 60, and (C) is the analysis result of the sound insulation structural floor 10 of the present invention.

[0045] In Fig. 6(A), m1 is the mass per unit area of the double floor (weight double floor 20), and m2 is the mass per unit area of the structural floor (sound insulation structural floor 10 or comparative structural floor 60). Also, k1 is the spring constant per unit area of the double floor (the combination of the spring by the support legs and the spring by the air layer), and k2 is the equivalent spring constant of the structural floor.

[0046] The mass per unit area m1 is set to 65 kg / m in Table 1 2 and m2 / m1 is set to 1.4 in (B) and 2.0 in (C). The spring constant k1 was set from the following equations (1) and (2) so that the natural frequency f1 is lower than the evaluation frequency (in this example, 32 Hz). Vibration period T1 = 2π√(m1 / k1) 0.5 ···(1) Natural frequency f1 = 1 / T1 ···(2) Also, the natural frequency of the structural floor (mass per unit area m2) was assumed to be in the range of 2 to 30 Hz, and the equivalent spring constant k2 was set to achieve each natural frequency.

[0047] In FIGS. 6(B) and 6(C), the horizontal axis represents the natural frequency of the structural floor, and the vertical axis represents the natural frequency of the two-mass system. Note that the natural frequency of the structural floor is set sufficiently lower than the evaluation frequency (63 Hz band) of the weight floor impact sound insulation performance. In this case, since the natural frequency of the structural floor varies depending on the floor structure (dimensions and fixing method) of the building, a range of 2 to 30 Hz is assumed and is indicated by the upward-sloping broken line A in the figure. Also, the natural frequency of the double floor (weight double floor 20) is also set lower than the evaluation frequency and is indicated by the horizontal broken line B in the figure.

[0048] In FIGS. 6(B) and 6(C), the solid line C is the first natural frequency of the two-mass system composed of the double floor and the structural floor, and the solid line D is the second natural frequency of the two-mass system composed of the double floor and the structural floor. From FIG. 6(B), in the case of a structural floor having a unit area mass 1.4 times that of the double floor, the second natural frequency of the two-mass system increases significantly compared to the case of the double floor alone and enters the 63 Hz band (45 Hz or higher), which is the evaluation frequency. On the other hand, in the case of a structural floor having a unit area mass twice that of the double floor, the increase of the second natural frequency of the two-mass system into the 63 Hz band is suppressed. Therefore, it can be seen that when installing the weight double floor 20 on a wooden floor, it is important to set the unit area mass of the wooden floor.

[0049] FIG. 7 is a diagram showing the analysis results of the two-mass system model when m2 / m1 is 2.5. From this figure, it can be seen that even when m2 / m1 = 2.5, the increase of the second natural frequency of the two-mass system into the 63 Hz band is suppressed.

[0050] According to the above-described embodiment of the present invention, the second natural frequency of the two-mass system composed of the weight double floor 20 and the sound insulation structural floor 10 is set lower than the evaluation frequency of the weight floor impact sound insulation performance. Also, the unit area mass of the sound insulation structural floor 10 is set to be 2 times or more and 2.5 times or less that of the weight double floor 20. With this configuration of the present invention, it is possible to suppress an increase in the secondary natural frequency of the two-mass system of the heavy double floor 20 due to the factors of the frame construction floor, and to more reliably ensure the effect of reducing the impact sound of the heavy floor by the sound insulation structure floor 10. In addition, by arranging a large number of joist perpendicular floor joists (joist reinforcing members 14) in the dead space between the joists, the total thickness of the wooden frame floor can be suppressed, and the mass per unit area of the floor can be ensured to a predetermined level without relying on special members such as weights.

[0051] Therefore, according to the configuration of the present invention, since the sound insulation structure floor 10 is made of wood or a woody material and does not use a material (such as an ALC board, an iron plate, or a precast concrete board) having a specific gravity larger than that of the cross-laminated timber, the mass per unit area of the sound insulation structure floor 10 can be reduced. In addition, since the secondary natural frequency of the two-mass system composed of the heavy double floor 20 and the sound insulation structure floor 10 is set lower than the evaluation frequency of the heavy floor impact sound blocking performance, the heavy floor impact sound can be reduced without using a material with poor workability compared to wood.

[0052] Note that the scope of the present invention is not limited to the above-described embodiments, is shown by the description of the claims, and further includes all modifications within the meaning and scope equivalent to the description of the claims.

Explanation of reference numerals

[0053] 1 Building body, 10 Sound insulation structure floor, 11 Joist support member, 12 Joist, 14 Joist reinforcing member, 16 Upper surface structure floor, 17a Structural plywood, 17b Plywood, 18a, 18b Hard gypsum board, 20 Heavy double floor, 22 Support leg, 24 Particle board, 25a, 25b Asphalt-based vibration damping material, 26 Plywood, 27 Flooring, 30 Suspended ceiling, 32 Suspension beam, 34 Suspension hardware, 36 Ceiling board, 37 Reinforced gypsum board, 38 Glass wool, 50 Comparative sound insulation floor, 60 Comparative structure floor, 62 Comparative joist, 64 Floor receiving wood, 100 Wooden sound insulation floor

Claims

1. A sound insulation structural floor fixed to the building body and extending horizontally, A weight double floor supported on the upper surface of the sound insulation structural floor and extending horizontally, A suspended ceiling suspended independently from the building body and extending horizontally, comprising a wooden sound insulation floor, The sound insulation structural floor comprises wood or wood-based materials and gypsum board, The secondary natural frequency of the two-mass system composed of the weight double floor and the sound insulation structural floor is set lower than the evaluation frequency of the weight floor impact sound insulation performance, The weight double floor includes an asphalt-based vibration damping material, and its natural frequency is set lower than the evaluation frequency, A wooden sound insulation floor in which the mass per unit area of the asphalt-based vibration damping material is set to be more than half of the weight double floor.

2. A sound insulation structural floor fixed to the building body and extending horizontally, A weight double floor supported on the upper surface of the sound insulation structural floor and extending horizontally, A suspended ceiling suspended independently from the building body and extending horizontally, comprising a wooden sound insulation floor, The sound insulation structural floor comprises wood or wood-based materials and gypsum board, A plurality of small beams fixed at both ends to the building body of the building and extending horizontally, A plurality of small beam reinforcement members extending horizontally perpendicular to the small beams and fixed at both ends to the small beams, The mass per unit area of the small beams is set to be equal to or more than that of the weight double floor, The secondary natural frequency of the two-mass system composed of the weight double floor and the sound insulation structural floor is set lower than the evaluation frequency of the weight floor impact sound insulation performance, The weight double floor includes an asphalt-based vibration damping material, and its natural frequency is set lower than the evaluation frequency, A wooden sound insulation floor in which the mass per unit area of the sound insulation structural floor is set to be 2 times or more and 2.5 times or less of the weight double floor.

3. The sound insulation structural floor further has an upper surface structural floor fixed to the upper surface of the small beams and extending horizontally, The upper surface of the small beam reinforcement member is lower than the lower surface of the upper surface structural floor, and there is a gap therebetween. The wooden sound insulation floor according to claim 2.

4. The core-to-core distance between adjacent small beam reinforcement members is set to be equal to or less than the core-to-core distance between adjacent small beams, The total cross-sectional area of the plurality of small beam reinforcement members connecting a pair of the small beams is set to be 1.5 times or more and 2.5 times or less of the cross-sectional area of a single small beam. The wooden sound insulation floor according to claim 2.

5. The suspended ceiling is located away from the small beams and the small beam reinforcement members, and is set so that their vibrations are not directly transmitted. The wooden sound insulation floor according to claim 2.

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