JP2018053513A - Low-floor double floor and method of constructing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-floor double floor that solves problems, associated with a height from a floor, leveling and height adjustment of a floor finishing material, strength of a floor joist, etc., that a conventional double floor has all at once.SOLUTION: A low-floor double floor A consists of: an architrave B which consists of floor joists 1-4 installed along four sides of an installation space respectively and then interconnected at four corners, and also having side floor joists 1a-4a installed on inner peripheral surfaces thereof respectively, and floor joint support legs 10 installed on both-end part lower surfaces of the floor joists 1-4; height-adjustable bed support legs 30 which are stood at predetermined intervals in the installation space encircled with the floor joists 1-4; a floor bed material 40 which is spread over the side floor joists 1a-4a and bed support legs 30 in the installation space encircled with the floor joists 1-4; and a floor finishing material 45 which is laid on the floor bed material 40. The side floor joists 1a-4a are different bodies from the floor joists 1-4, and fitted to side faces of the floor joists 1-4 respectively at positions obtained by subtracting the sum of thicknesses of the floor bed material 40 and floor finishing material 45 constructed in the installation space encircled with at least the floor joists 1-4 from upper surfaces 1b-4b of the paired floor joists 1-4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a low floor double floor that can be quickly constructed even on a floor surface of a wide space with unevenness and an efficient construction method thereof.

  In recent years, it has become popular to provide fashionable temporary or permanent talk spaces and cafe spaces that incorporate a Western-style open atmosphere with simple enclosures in the free space of many multi-storey buildings such as apartment buildings and office buildings. Yes. In recent years, floors of such a space have been adopted to have a double floor structure in order to have wiring cords, equipment piping, or the like that impair the appearance of the floor under the floor or for sound insulation to the downstairs.

  Conventionally, this type of double floor is combined with a rectangular joist with a thickness that can withstand several times the total load on the double floor, and the height adjustable legs with screw bolts on the bottom of each corner. Can be brought into the installation space, the legs can be stretched according to the unevenness of the floor, the top surface of each joist is leveled, and the screw can be extended inside the wheel. Install the support legs at regular intervals, stretch the floor base material on it, adjust the height of the support legs to level the floor base material, and finally stretch the floor finish on the floor base material The method of doing was taken.

If the installation space is small, only a thin joist base is sufficient, but if the installation space becomes wider, the joists that make up the base wheel need a long span to cover the installation space, and therefore can withstand the bending stress. The thick thing that is used is used. In some cases, an auxiliary bar is further attached between the joists. Usually, there is no leg attached to the auxiliary bar, and the height is adjusted by the legs provided at both ends in a floating state.
In the double floor using the above-mentioned wheel ring, it is necessary to make the thickness of the joist considerably thicker from the viewpoint of strength as described above, so if floor base material and floor finish material are stretched on the upper surface of the joist, the floor base Since the thickness of the wood and floor finish is added to the thick joists, the height from the floor surface to the tread (upper surface) of the floor finish material of the double floor becomes too high, which hinders the climbing of the double floor It was pointed out that the ceiling was lowered by the height of the double floor as a reaction to the problem, and the feeling of pressure in the installation space increased. Also, it was very troublesome to bring a large pedestal into the free space.

Then, the idea of the double floor which can make the tread height of a double floor easy even if the installation space is large as well as when the installation space is wide is proposed (Patent Document 1). The joist unit used for this double floor is a long joist with a plurality of recesses on the lower surface of the joist unit with a predetermined interval, and both sides of the joist to eliminate insufficient strength due to the installation of a plurality of recesses. It is comprised by the reinforcing material attached to each, and the screw-type support bolt with a floor-contact base provided so that the thread part may be accommodated in this recessed part.
A driver insertion groove is formed on the upper surface of the support bolt, and the joist can be moved up and down by rotating the support bolt.

  In order to construct this double floor, support legs prepared separately from the joist unit are used. First, the joist unit is arranged along the inner periphery of the room, and the support bolt is rotated. Level the top surface of each joist unit, align the height of each joist unit, adhere and fix the flooring pedestal on the floor, and then place the support legs at predetermined intervals on the inner area surrounded by the joist unit on all four sides. Install and finely adjust the height from the floor to match the height of the joist, and place the floor base material on the upper surface of the lower joist and the upper surface of the support leg, and place it flush with the floor base material. Level the top surface, and then drive the self-tapping screw into the support leg from the top surface side of the floor base material, fix the floor base material to the support leg, and finally lay the floor finish on the floor base material To do.

The height of the joist unit can be lowered by providing a recess and inserting a part of the support bolt into the recess, but reinforcing materials on both sides are indispensable to solve the lack of strength. Even if a reinforcing material is stretched over the entire surface of both sides, the joist and the reinforcing material cannot be removed for the above reasons, so a reinforcing material having a large width is required.
In addition, the thickness of floor base materials and floor finish materials varies, and it is necessary to determine the height of joist unit and support legs according to the site where they are used. It is necessary to move it a lot, and it takes a lot of time to level and adjust the height.

JP 2014-211055 A

  The present invention relates to the problem of height from the floor in conventional double floors, leveling and height adjustment of floor finishing materials by operating support bolts and support legs after tensioning floor finishing materials, The technical problem is to provide a low-floor double floor that solves the problems of strength of steel and its efficient construction method.

The low floor double floor A according to claim 1 is:
Installed along the four sides of the installation space, connected to each other at the four corners, the joists 1 to 4 having the joists 1a to 4a installed on the inner peripheral surfaces thereof, and the lower surfaces of both ends of the joists 1 (2 to 4) Each of which is installed, and a base wheel B constituted by a joist support leg 10 capable of adjusting the height of the joists 1-4,
A base support leg 30 which is erected at a predetermined interval in an installation space surrounded by joists 1 to 4 and is adjustable in height;
In the installation space surrounded by the joists 1 to 4, the floor joists 1a to 4a and the floor base material 40 stretched on the base support legs 30, and
In the double floor A composed of the floor finishing material 45 laid on the floor base material 40,
The floor joists 1a to 4a are separate from the joists 1 to 4, and are installed in the installation space surrounded by at least the joists 1 to 4 from the upper surfaces 1b to 4b of the joists 1 to 4 to be paired. 40 and the floor finishing material 45 are attached to the side surfaces of the joists 1 to 4 at positions obtained by subtracting the sum of the thicknesses of the floor finishing materials 45, respectively.

  Since the corner joists 1a to 4a are attached to the positions as described above, the pair joists 1 to 4 are matched to the floor base material 40 and the floor finishing material 45 to be constructed at each construction site. 4 can be attached to the side surface (on the inner surface side). In other words, in constructing the low-floor double floor A, the thick joists 1 to 1 that do not require a reinforcing material regardless of the thickness of the floor base material 40 and the floor finishing material 45 constructed at each construction site. 4 can be used. Accordingly, it is possible to construct even a wide installation space that requires long span joists 1 to 4.

The construction method of the low floor double floor A according to claim 2 is a case where the double floor A is constructed in a narrow installation space.
A joist 1-4 in which the joist support legs 10 capable of adjusting the height are installed on the lower surfaces of both ends, a joist 1a-4a separately from the joists 1-4, a floor base material 40 and a floor finishing material 45. With the construction method of low floor double floor A constructed using
At the position obtained by subtracting at least the sum of the thicknesses of the floor base material 40 and the floor finishing material 45 to be constructed from the upper surfaces 1b to 4b of the joists 1-4, the joists 1a to 4a are one of the joists 1-4. Attach to the side of
The first joist 1 is installed along one side of the installation space, with the joist 1a inside the installation space,
By operating the joist support legs 10 at both ends of the first joist 1 and adjusting the height of the upper surface 1b of the first joist 1 to be a predetermined height from the floor G and to be horizontal,
Next, the second and third joists 2 and 3 are installed along the sides adjacent to the one side of the installation space with the joists 2a and 3a inside the installation space, respectively.
By operating the joist support legs 10 at both ends of the second and third joists 2,3, the upper joists 2a, 3a of the second joists 2,3 and the upper joists 1a of the first joists 1 are used. And adjusting the upper surfaces of the second and third joists 2 and 3 so that the upper surfaces of the joists 2a and 3a are horizontal with respect to the upper surfaces of the joists 1a of the first joists 1 and
On the open end side of the second and third joists 2.3, install the fourth joist 4 along the remaining side of the installation space with the joist 4a inside the installation space,
By operating the joist support legs 10 at both ends of the fourth joist 4, the upper surfaces of both joists 4a of the fourth joists 4 are the upper surfaces of the joists 2a and 3a of the second and third joists 2.3. Adjusted to match
In the region surrounded by the first to fourth joists 1-4, the floor base material 40 is stretched over the joists 1a-4a,
A floor finishing material 45 is stretched on the floor base material 40.

The construction method of the low floor double floor A according to claim 3 is a case where the double floor A is constructed in a wide installation space.
In the construction method of the low-floor double floor A according to claim 2, a base support leg 30 capable of adjusting the height is added,
After the joists 1 to 4 are installed on the four sides of the installation space, the floor foundation support legs 30 are installed at predetermined intervals in the area surrounded by the first to fourth joists 1 to 4,
In the region surrounded by the first to fourth joists 1-4, the floor base material 40 is stretched over the floor joists 1a-4a and the floor base support legs 30.

  Since the present invention uses “Kitakita 1a to 4a”, the floor base material 40 and the floor finishing material 45 can be stretched in a region surrounded by the first to fourth joists 1 to 4. . Therefore, it is possible to use the thick joists 1 to 4 which are at least the sum of the thicknesses of the floor base material 40 and the floor finishing material 45, and increase the strength of the joists 1 to 4 despite the low floor double floor A. I can do it. In other words, it is possible to deal with a wide installation space with thick joists 1 to 4 that do not require a reinforcing material.

It is a perspective view of the construction example of the low floor double floor of this invention. It is a top view of the corner | angular part of the construction part of FIG. It is a perspective view of the base ring which assembled the joist of the present invention into the rectangle. FIG. 4 is a front view of FIG. 3. It is an expanded sectional view of the corner | angular part of the construction part of FIG. It is an expanded sectional view which shows the attachment state of the joist support leg of the joist end of this invention. It is an expanded sectional view which shows the attachment state of the floor base support leg used for this invention.

  Hereinafter, the present invention will be described in detail according to illustrated embodiments. In the embodiment shown in FIG. 1, the floor G on which the double floor A is constructed is a base floor made of a concrete slab having some unevenness and inclination, and a floor such as a P tile or a recently popular flat stone board. The material is stretched. Therefore, the upper surface of the flooring material is also affected by this influence and has unevenness and inclination. When a floor material such as a slab is used, the surface of the floor material itself has some unevenness, and the unevenness and inclination of the construction floor G cannot be avoided.

The low-floor double floor A of the present invention is a low-floor double floor in a narrow installation space by assembling the joists 1 to 4, the joists 1a to 4a, the joists support legs 10, the floor base material 40, and the floor finishing material 45. A is constructed, and the base support leg 30 is added to the large installation space.
First, the low floor double floor A in a large installation space will be described. Since the low floor double floor A in a narrow installation space having a simpler structure than this is not shown, the description of the former is used as the description of the latter, and only different parts will be described mainly.

As shown in FIG. 1 to FIG. 6, the joists 1 to 4 are formed of, for example, a solid prism having a width of 90 mm and a height of 90 mm, or a prism made of a single-plate laminated material. A length of 4,000 to 7,000 mm and a length of 2,000 to 4,000 mm on the short side are used. The height of the joists 1 to 4 is greater than the sum of at least the thickness of the floor base material 40 and the floor finishing material 45 and the height of the joists 1a to 4a.
As shown in FIGS. 3 and 6, the joists 1 to 4 are provided with accommodation holes 14 for accommodating the screw portions 12 of the joist support legs 10 on the lower surfaces of both side portions. And the adjustment hole 6 from the upper surfaces 1b-4b to the accommodation hole 14 is drilled at both ends of the joists 1-4.

  The joists 1a to 4a are prepared separately from the joists 1 to 4 and used in pairs. Similarly, the joists 1a to 4a are formed of solid prisms having a width of 30 mm and a height of 40 mm, or prisms made of a single plate laminate. .

  The joist support leg 10 is a metal that rotatably supports the screw portion 12 having a male screw engraved on the outer peripheral surface above the flange portion 12c and the screw portion 12 below the flange portion 12c through the rotation hole 11a. Or a base 11 made of hard resin, attached to the lower surface of the base 11, and a vibration-absorbing material that attenuates the impact from the floor finishing material 45 to prevent vibration transmission to the floor G and enhances sound insulation and shock relaxation A buffer seat 11e (for example, soft rubber) and a nut member 13 screwed to the screw portion 12 are provided. A projecting portion 13a through which the female screw hole passes is projected on the upper surface of the nut member 13, and the joist 1 -4 are press-fitted into the storage holes 14 at both ends and fixed with screws. Note that a retaining ring 11b for retaining is attached to the lower end of the threaded portion 12, and a driver groove 12d is formed on the upper end surface.

The base support leg 30 has the same structure as the joist support leg 10 and includes a bolt leg portion 32, a support base 31, a support nut portion 33, and a support plate portion 34 as shown in FIG.
The support base 31 made of metal or hard resin is formed with a rotation hole 31a penetrating vertically, and the non-threaded portion of the bolt leg portion 32 is rotatably inserted, and the flange portion 32c of the non-screw portion is supported by the support base 31. It hits the top surface of. A retaining ring 32b for retaining is fitted at the lower end of the non-screw portion (the downward projecting portion of the rotation hole 31a).
The bolt leg portion 32 is made of metal or hard resin, and a male screw portion 32a is engraved on the upper half thereof, and a driver groove 32d is formed on the upper end surface.
The supporting nut portion 33 is also made of metal or hard resin, and a female screw hole is formed in the center thereof, and an outer flange portion 33a is projected from the entire upper end portion. The male screw portion 32a of the bolt leg portion 32 is screwed into the female screw hole of the supporting nut portion 33 so as to be movable up and down.
A wooden support plate portion 34 is fixed to the outer flange portion 33a, and a through hole for inserting a driver is formed in a portion corresponding to the female screw hole of the support plate portion 34.

  Between the lower surface of the bolt leg portion 32 and the floor surface G, a rubber seat is used to make it easier to absorb vibrations from the center portion (region surrounded by joists 1 to 4) of the low floor double floor A. A vibration absorbing seat 31e is laid as necessary.

  The floor base material 40 is composed of, for example, a rectangular particle board, plywood or OSB plywood (also referred to as OSB: Oriented Strand Board). Thickness T varies, and there are 12, 15, 19, 21, 24, and 30 mm in plywood. There are various sizes, around 1m x 2m.

  In the example shown in FIG. 1, a flooring panel is used as the floor finish material 45, and the floor finish material 45 is laid on the floor base material 40 in a state where the fruits provided on the side portions are combined with each other. Finally, it is fixed with a nail or adhesive that is inconspicuous.

An example of the construction procedure of the low floor double floor A using the above members will be described. The joists 1 to 4 are cut in advance according to one side of a rectangular or square installation space, and joist support legs 10 are attached to the lower surfaces of both ends.
First, the thicknesses T and W of the floor base material 40 and the floor finishing material 45 used at the site are examined by measurement or catalogs, respectively.
Next, the joists 1a to 4a are fixed to only one side of the prepared joists 1 to 4 with the jojo fixing members 5 such as screws, but the joists fixing member 5 is fixed. The position is lowered from the upper surfaces 1b to 4b of the joists 1 to 4 to the lower surface side by a dimension obtained by adding a margin of 2 to 3 mm (this portion is indicated by symbol S in FIG. Fixed to. Thereby, when it fixes only to one side surface of the joists 1-4, the upper surface of the joists 1a-4a becomes a construction standard.

In this way, one joist 1 out of the joists 1 to 4 with the joists 1a to 4a mounted at predetermined positions is arranged along one side of the installation space. The margin joist 1a is arranged so as to be inside the installation space.
Since the floor G has irregularities as described above, the side where the joists 1 are installed also has irregularities, and the installed joists 1 are also inclined in accordance with the irregularities. Therefore, a screwdriver 12 is inserted into the adjustment hole 6 and the screw portion 12 is rotated by the driver groove 12d, whereby the joist support leg 10 at one end of the installed joist 1 is operated up and down, and the one end portion The height of the upper surface 1b of the joist 1 (or the upper surface of the hot jok 1a) is adjusted to the height of the upper surface of the joist (or the upper surface of the hot jok) of the planned low floor double floor.

  Subsequently, an instrument such as a spirit level is placed on the upper surface 1b of the joist 1 (or the upper surface of the joist 1a), and the joist support leg 10 at the other end is operated in the same manner to adjust the level of the joist 1. put out. As a result, the upper surface 1b of the joist 1 (or the upper surface of the kimono joist 1a) becomes the height of the upper surface (or the upper surface of the jojo joist) of the planned low-floor double floor.

Next, select the second and third joists 2.3 corresponding to the two sides (two orthogonal sides in the case of a rectangle) that are adjacent to one side of the installation space where the first joists 1 are arranged. , And place each on the corresponding side.
The upper surfaces 2b and 3b of the ends of the second and third joists 2 and 3 (or the upper surfaces of the joists 2a and 3a) in contact with the ends of the first joists 1 are the upper surfaces of the end portions of the first joist 1. The joist support leg 10 at the end is similarly operated so as to match 1b (the upper surface of the joist 1a).
Thereafter, similarly, a device such as a spirit level is placed on the upper surfaces 2b and 3b of the second and third joists 2 and 3 (or the upper surfaces of the joists 2a and 3a), and the joists support legs at the other ends. 10 is operated in the same manner to obtain the level of the joists 2.3. The upper surfaces 2b and 3b of the second and third joists 2.3 are aligned with the upper surfaces 1b of the first joists 1 (or the upper surfaces of the joists 1a).

  The last remaining joist 4 is arranged between the free ends of the second and third joists 2.3 and the ends are brought into contact with each other. Then, the joist support legs 10 at both ends of the fourth joist 4 are operated in the same manner, and the upper surfaces 2b and 3b (or the jojo 2a and j The upper surface 4b of the end of the fourth joist 4 (or the upper surface of the joist 4a) is matched with the upper surface of 3a. Thereby, joists 1-4 are arranged along the four sides of the installation space.

Connection of the contact ends of the joists 1 to 4 is performed by driving a U-shaped connecting metal fitting 20 such as a squirrel over the contact end. When the adjustment of the second and third joists 2.3 is completed with respect to the first joists 1, the connection of the joists 1-4 with the connecting metal fitting 20 is the second with respect to the second joists 2.3. When the adjustment of the four joists 4 is finished, the connections may be made sequentially, or when the four joists 1-4 are finished, the connections may be made.
Further, instead of the U-shaped connecting fitting 20 such as a squirrel, it is also possible to use a connecting fitting such as a through bolt or nut, although not shown, by joining with an adhesive.
By completing the joining of the four joists 1 to 4, one rectangular (or square) trolley B is completed by site construction. This wheel B is supported by two joist support legs 10 adjusted in accordance with the unevenness of the floor surface G at the four corners, and does not rattle.

  Subsequently, the base support legs 30 are erected at predetermined intervals on the inner side of the base wheel B (installation space surrounded by the joists 1 to 4). Although not shown in the drawings, when the reference yarn (not shown) attached to the upper surface of the outer joists 1a and 4a (2a and 3a) is opposed so as to pass the installation position of the base support leg 30, the joists 1a and 4a are opposed to each other. (2a, 3a), the base support leg 30 is erected at a point immediately below the intersection of the reference yarns, and the height is adjusted in advance by operating the bolt leg 32. Since the height of the reference yarn coincides with the reference height of the joist 1a, if the height of the base support leg 30 is adjusted based on the height of the reference yarn, accurate height adjustment can be performed in advance. . The base support leg 30 whose height has been adjusted is adhered and fixed to the floor G as required.

When the installation of the base support legs 30 is completed, the floor base material 40 is stretched on the floor joists 1a to 4a and the floor base support legs 30 in the region surrounded by the first to fourth joists 1-4. Since the base support leg 30 is located at the corner portion of the adjacent floor base material 40, the fruit of the portion is cut out and stretched in the above region in a state where it is actually joined at a portion other than the corner portion as shown in FIG. The
At this point, since the height adjustment is almost completed as described above, it is considered that the level of the stretched floor base material 40 has almost come out. While using the screw, a screwdriver is inserted into the corner hole 40s, and the bolt leg 32 is rotated in the driver groove 32d of the bolt leg 32, and the support nut part 33 is slightly moved up and down to accurately level the floor base material 40. Put out.
When the installation of the floor base material 40 is completed in this manner, the base fixing member 41 such as a screw is driven and fixed from the floor base material 40 to the support plate portion 34 of the floor base support leg 30.
Finally, the floor finishing material 45 is stretched on the laid base fixing member 41 and fixed on the base fixing member 41 by nail fixing or adhesion at an inconspicuous position. Since the floor finishing material 45 is constructed in an area surrounded by the first to fourth joists 1-4, the joists 1-4 are exposed around the floor finishing material 45 with the margin S increased. To do.

FIG. 1 is an example in which a plurality of low floor double floors A as described above are installed side by side, and a frame C having columns 50 is installed between adjacent low floor double floors A.
As described above, the other joists 2 to 4 are assembled on the basis of one joist 1 (the first joist 1), and the inner base with the upper surface of the joist 1a of the first joist 1 as the reference plane. Since the support legs 30 are constructed in sequence, the height and level can be adjusted with a single adjustment, and the construction time can be significantly reduced compared to conventional adjustments that had to be repeated little by little. It was.

  In the above case, the reference yarn is used, but the reference yarn is not used, and the standing position of the base support leg 30 is marked in advance on the floor G of the installation space with inking. After the base support leg 30 is erected and fixed at that position, the floor base material 40 is stretched as described above, and the height of the base support leg 30 is raised and lowered as described above with a screwdriver so as to be horizontal. It may be.

  Next, it is construction of a low floor double floor in a narrow installation space. In this case, the floor base material 40 is not provided between the joists 1a and 4a (2a and 3a) when facing each other without providing the base support legs 30. And the floor finishing material 45 is laid. Other than that, it is the same as the construction of the low floor double floor in the wide installation space.

A: low floor double floor, B: trolley, C: frame, G: floor surface, S: marginal height, W: thickness of floor finishing material, T: thickness of floor base material, 1-4: joists DESCRIPTION OF SYMBOLS 1a-4a: Tokita, 1b to 4b: Upper surface, 5: Tokita fixing member, 6: Adjustment hole, 10: Joist support leg, 11: Base, 11a: Rotation hole, 11b: Retaining ring, 11e: Buffer seat, 12: screw part, 12c: collar part, 12d: driver groove, 13: nut member, 13a: convex part, 14: storage hole, 20: connecting bracket, 30: base support leg, 31: support base, 31a: rotation hole 31e: vibration absorbing seat, 32: bolt leg portion, 32a: male screw portion, 32b: retaining ring, 32c: collar portion, 32d: driver groove, 33: support nut portion, 33a: outer flange portion, 34: support plate Part, 40: floor base material, 40s: corner hole, 41: base fixing member, 45: floor finish material, 0: pillar.

Claims (3)

Installed along the four sides of the installation space, connected to each other at the four corners, and installed on the inner peripheral surface of the joist and the lower surfaces of both ends of each joist, respectively, to adjust the height of the joist A pedestal composed of joist support legs with adjustable height,
A base support leg that is erected at a predetermined interval in an installation space surrounded by joists and is adjustable in height,
In the installation space surrounded by joists, floor base materials stretched on the joists and base support legs,
In the double floor composed of the floor finishing material laid on the floor base material,
Toki jota is a separate body from joists, and the joists at the position obtained by subtracting the sum of the thickness of the floor base material and floor finishing material to be constructed in the installation space at least surrounded by the joists from the upper surface of the paired joists Low floor double floor characterized by being attached to each side of the floor. Construction method of low floor double floor constructed using joists with adjustable joist support legs on the bottom of both ends, joists separate from joists, floor base materials and floor finish materials so,
At the position where the sum of the thickness of the floor base material and floor finishing material to be constructed is subtracted from the upper surface of the joist, attach the joist to one side of the joist when paired,
With the joist on the inside of the installation space, the first joist is installed along one side of the installation space,
By operating the joist support legs at both ends of the first joist, the height of the upper surface of the first joist is adjusted to be a predetermined height from the floor surface and horizontal,
Next, the second joist and the third joist are installed along the side adjacent to the one side of the installation space with the joist inside the installation space,
By manipulating the joist support legs at both ends of the second and third joists, the upper surface of the joists of the second and third joists match the upper surfaces of the joists of the first joists and the first joists of the first joists Adjusting the top surface of the second and third joists so that the upper surfaces of the joists are horizontal,
On the open end side of the second and third joists, install the fourth joists along the remaining side of the installation space with the joists inside the installation space,
Manipulating the joist support legs at both ends of the fourth joist and adjusting the upper surface of both ends of the joist of the fourth joist to match the upper surfaces of the joists of the second and third joists,
In the area surrounded by the first to fourth joists, the floor base material is stretched over the joists,
A method for constructing a low floor double floor, characterized in that a floor finishing material is stretched on the floor base material. In the construction method of the low-floor double floor according to claim 2, a base support leg capable of height adjustment is added,
After installing joists on the four sides of the installation space, install floor foundation support legs at predetermined intervals in the area surrounded by the first to fourth joists,
A method for constructing a low floor double floor, characterized in that, in a region surrounded by first to fourth joists, a floor base material is stretched over the floor joists and the floor base support legs.