JPH10280554A - Ceiling structure, building unit and building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction of distances among ceiling beams, and to obviate the heightening of the height of the ceiling beams by installing ceiling materials under the ceiling beams consisting of shape steel while mounting board materials on the ceiling beams. SOLUTION: The skeleton of the building unit 1 is formed of columns 11, ceiling beams 12 and floor beams 13. Ceiling beams 14 are bridged over the ceiling beams 12 corresponding to a ceiling section. Ceiling boards 15 are set up onto the undersides of the ceiling beams 14 while board materials 16 are fitted onto the top faces of the ceiling beams 14, and a ceiling is formed. In floor structure, floor beams 15 are bridged over the opposed pairs of the floor beams 13 framed in a rectangular shape. Square pole-shaped sectional floor joists 16, in which one sides of steel plates are opened, are installed onto the floor beams 15. Accordingly, the ceiling beams 14 are difficult to be deflected, and the ceiling beams can be mounted and executed easily without reducing distances among the ceiling beams while the ceiling structure having fire- resistive construction can be manufactured because no wood is used for the ceiling beams 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceiling structure, a building unit using the ceiling structure, and a building provided with these ceiling structures or building units.

[0002]

2. Description of the Related Art A unit building is disclosed in Japanese Patent Publication No. 62-6222.
As described in Japanese Patent Publication No. 4 (1993), a box-shaped, transportable, fixed-size, internally and externally finished building unit is manufactured at a factory in advance, and a plurality of such building units are installed at a construction site. It is transported and assembled at a construction site to form a building, and is widely used because it has a feature of being a standardized building with short on-site construction period and high dimensional accuracy.

This unit building has four metal pillars arranged at four corners of a square, and four metal floor beams framed in a square shape by connecting the lower ends of the four pillars, A building unit having a skeleton consisting of four metal ceiling beams framed in a square shape by connecting the upper ends of four pillars is assembled vertically and vertically and front and rear, and the ceiling structure of this building unit As described in Japanese Patent Publication No. 61-3943, a wooden ceiling beam is fixed to a lower flange opposite to a metal ceiling beam framed in a square shape, and under the ceiling beam. It is fitted with ceiling material.

Japanese Patent Application Laid-Open No. Hei 3-212551 discloses that a ceiling plate is attached to the lower surface of a ceiling beam made of wood, a surface material is attached on the ceiling beam, and a bridge is further bridged between the ceiling beams. A ceiling structure provided with a plate material is described.

Japanese Patent Application Laid-Open No. Hei 8-199729 discloses a beam member in which a 3.2 mm-thick steel plate is formed into a special shape having a cross section formed by connecting apex angles of triangles.

[0006]

Since the wooden ceiling beam has a small Young's modulus and is easily bent, it is necessary to reduce the distance between the ceiling beams or increase the height of the ceiling beam.

However, in order to reduce the distance between the ceiling beams, it is necessary to provide a large number of ceiling beams, which not only increases the cost of the building unit but also complicates the work of mounting the ceiling beams. However, when the height of the ceiling beam is increased, the wooden ceiling beam is not only expensive, but also the distance between the floor and the ceiling is reduced, resulting in a problem that the building is not easily habitable. Further, wood has a problem that it is difficult to obtain a long object and burns.

On the other hand, as described in the above-mentioned Japanese Patent Application Laid-Open No. Hei 8-199729, steel beams and the like are characterized by having a large Young's modulus and being difficult to bend. Therefore, an attempt was made to apply a 3.2 mm thick steel plate conventionally used for ceiling beams and the like to the ceiling beams, but this steel ceiling beam became a cold bridge (thermal bridge), Therefore, there is a problem that dew condensation occurs and heat insulation performance is reduced. In addition, there is also a problem that a steel nail having a thickness of 3.2 mm cannot be hit with a normal nail when attaching a ceiling material.

In view of the foregoing, it is an object of the present invention to provide a ceiling structure that does not reduce the distance between ceiling beams and does not increase the height of ceiling beams.
Furthermore, a ceiling material can be attached with ordinary nails, the ceiling beam is hardly bent, and the insulation performance does not decrease even if a steel ceiling beam is used. This ceiling structure is used. It is an object to provide building units and buildings comprising these ceiling structures or building units.

[0010]

According to the first aspect of the present invention,
A ceiling structure in which a ceiling material is attached below a ceiling beam, wherein the ceiling beam is made of shaped steel, and a ceiling material is attached below the ceiling beam and a plate material is attached on the ceiling beam. It is a ceiling structure characterized by the above.

According to a second aspect of the present invention, there is provided a ceiling structure having a ceiling material attached below a ceiling beam, wherein the ceiling beam is made of a shaped steel, and a ceiling material is provided below the ceiling beam. A ceiling structure characterized by being attached and a plate material attached to a ceiling beam via a non-metallic body.

The invention described in claim 3 is the first or second invention.
The ceiling structure according to any of the preceding claims, wherein a heat insulating material is laid on the ceiling material at a height in contact with a lower surface of the plate material.

According to a fourth aspect of the present invention, there is provided the ceiling structure according to any one of the first to third aspects, wherein a heat insulating material is laid on the plate material.

According to a fifth aspect of the present invention, there is provided a building unit comprising the ceiling structure according to any one of the first to fourth aspects.

According to a sixth aspect of the present invention, there is provided a building provided with the ceiling structure according to any one of the first to fourth aspects. This building also includes a building provided with the building unit according to claim 5.

The plate material to be mounted on the ceiling beam in the above invention is not limited so long as it can be used for wiring, piping, etc., so long as it does not break even when a person rides on it. Good. As such a plate, a wooden plate such as a particle board or a plywood is preferably used because it is light and easy to handle. This plate is preferably mounted so as to bridge between the ceiling beams.

The section steel in the first aspect of the present invention includes a channel section steel, a lip channel section steel, a Z section steel, a lip Z section steel, a hat section steel, a lip hat section steel, and the like. Like these shaped steels, those having substantially parallel upper and lower surfaces are preferable because ceiling materials and plate materials are easily attached. Further, as described in Japanese Patent Publication No. 8-199729, a long body having a cross-section in which vertexes of a triangle are connected may be used.

As the non-metallic body in the second aspect of the present invention, a material having better heat insulation performance such as wood brick is used.

The ceiling beam preferably has a thickness of 0.5 to 1.0 mm. The reason why the thickness is preferably 0.5 to 1.0 mm is that if the thickness is less than 0.5 mm, the mechanical strength is small and the ceiling beam cannot be used, and if it exceeds 1.0 mm, nailing is difficult.

The heat insulating material according to the third and fourth aspects of the present invention includes a synthetic resin foam, cork,
Examples include organic heat insulating materials such as felt and soft fiberboard, and inorganic heat insulating materials such as glass wool, rock wool, asbestos, and cellular concrete. Among them, glass wool is preferably used because it is nonflammable and has excellent heat insulating properties.

According to the fourth aspect of the present invention, if a hard heat insulating material is used as the heat insulating material laid on the plate material,
When a building is constructed on site, a person can ride on it, and work such as wiring and piping becomes easy. Examples of the hard heat insulating material include a hard synthetic resin foam board such as a hard urethane foam board and a hard polystyrene foam board.

[0022]

According to the first aspect of the present invention, since the ceiling beam is made of shaped steel, the ceiling beam is hardly bent, and the ceiling beam can be easily installed without reducing the distance between the ceiling beams. Because the height of the ceiling beams is not increased, the distance between the floor and the ceiling can be increased, and since wood is not used for the ceiling beams, a fire-resistant ceiling structure can be obtained. .

Further, since the plate is mounted on the ceiling beam, the plate can be used as a scaffolding plate or a work plate for construction work such as wiring and piping when the building is constructed. When a floor structure on an upper floor is placed on the floor, it can be used as a support base for supporting an underfloor storage.

According to the second aspect of the present invention, in addition to the operation of the first aspect of the present invention, the plate member is mounted on the ceiling beam with a non-metal body interposed therebetween and does not directly contact the channel steel. Therefore, the channel steel is prevented from becoming a cold bridge (hot bridge), and the heat insulating performance is not reduced, and there is no dew condensation at that portion.

According to the third aspect of the present invention, the heat insulating material is laid on the ceiling material at a height in contact with the lower surface of the plate material. Is prevented from decreasing.

In the fourth aspect of the present invention, since the heat insulating material is laid on the plate material, the heat insulating material prevents a decrease in the heat insulating property due to the use of the shaped steel for the ceiling beam.

According to the fifth aspect of the present invention, the first aspect is provided.
Since the building unit is provided with the ceiling structure according to any one of the first to fourth aspects, the ceiling structure is the same as the floor structure according to the first to fourth aspects of the invention. Therefore, the bending of the ceiling beam is small and the mechanical strength is large. Further, the plate material on the ceiling beam can be used as a scaffold plate or a work plate at the time of assembling and constructing the building unit, and construction work such as wiring and piping can be performed. Further, this plate member can be used as a support base for supporting an underfloor storage or the like when a floor structure on the floor is placed on the ceiling structure.

According to the sixth aspect of the present invention, there is provided the first aspect.
Since the building is provided with the ceiling structure according to any one of the above-described items 4, a building having a ceiling with a small bending of the ceiling beam and a large mechanical strength is constructed. .

[0029]

Embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 shows an embodiment of the present invention.
(A) is an explanatory view showing the skeleton of the building unit, (B) is a cross-sectional view of the AA portion of (A), (C) is an enlarged view of the B portion of (A), (D) Is a perspective view of a ceiling beam.

In FIG. 1, reference numeral 1 denotes a building unit (short side length 2464 mm, long side length 4740 mm, height 28
30 mm), and the skeleton of this building unit 1 is shown in FIG.
As shown in (a), four steel columns 11 and 1 each having a rectangular cross section and standing at four corners of a rectangle having short sides and long sides.
1, 11, 11; and four ceiling beams 12, 12, 12, 12, made of channel steel having a U-shaped cross section connecting the upper ends of the four columns 11 along the short side and the long side, It comprises four floor beams 13, 13, 13, 13 made of four channel-shaped channel steels connecting the lower ends of the four columns 11 along the short side and the long side.

On the ceiling part of the building unit 1, opposed ceiling beams 12, 12 are made of metal ceiling beams 14.
The ceiling material 15 is attached to the lower surface of the ceiling beam 14, and a thickness of 12 m
m, a plate material 16 made of a particle board having a width of 450 mm
Are attached to form a ceiling.

As shown in FIG. 1A, the plate member 16 is preferably mounted so as to extend between the ceiling beams 14, because it is supported by the metal ceiling beams 14. The plate 16 may be attached over the entire surface.

The long side ceiling beam 12 has a width of 100 mm,
A U-shaped cross-section steel having a height of 200 mm and a thickness of 4.5 mm is used, and a U-shaped cross-section steel having a width of 75 mm, a height of 200 mm, and a thickness of 3.2 mm is used for the short side ceiling beam 12. As shown in FIG. 1A, the grooves are mounted between the upper ends of the pillars 11 with their grooves facing each other.

As shown in FIG. 1 (d), upper and lower flanges 141, 141 of which the main body part is substantially parallel upper and lower surfaces, and the upper and lower flanges 141, 141 are used as the ceiling small beams 14.
A web 142 connecting one edge of the
A lip 143 extending inward from the other edge of the 141;
143 is used, and a lower flange portion is cut off at both ends to form a mounting piece 144.

The ceiling beam 1 made of lip channel steel
Reference numeral 4 denotes a main body part having a width of 75 mm, a height of 125 mm, and a thickness of 0.6 mm. As shown in FIG. And the attachment piece 144 is attached to the lower flange 121 of the ceiling beam 12 by welding. The mounting piece 144 is a lower flange 14 of the main body.
The reason for providing a step above 1 is to prevent cold bridges (thermal bridges). In addition, as a method of attaching the ceiling beam 14 to the ceiling beam made of the channel steel, rivets,
A joining method using a screw, a press joint (caulking), adhesion, or the like may be used.

In the floor portion, the long side floor beams 13 are provided.
As for, width 75mm, height 150mm, thickness 4.5mm
Is used. As the floor beam 13 on the short side, a U-shaped section steel member having a width of 50 mm, a height of 150 mm, and a thickness of 3.2 mm is used, as shown in FIG. Thus, it is attached between the lower ends of the pillars 11.

Then, as shown in FIG. 1C, a square tubular steel floor beam 17 having a width of 75 mm, a height of 125 mm and a thickness of 2.3 mm having a U-shaped mounting piece 19 attached to the end surface. Are installed on the floor beams 13 on the long sides opposed to each other substantially parallel to each other with the upper surface substantially horizontal, and the mounting pieces 19 are attached to the floor beams 1.
3 and the floor beam 17 is attached to the floor beam 13.

On the floor beam 17, six floor joists 18 each of which is formed of a metal cylinder having a square cross section (width: 38 mm, height: 46 mm, thickness: 0.6 mm) with one side opened are placed substantially in parallel with each other. , The lower surface is welded.
Then, a floor material made of a particle board is placed on the floor joist 18, and a nail is driven into the floor joist 18 from above the floor material and attached.

In the place where the outer wall is provided, the ceiling beam 12 is provided.
A stud 20 is mounted between the stud 20 and an outer wall material and an inner wall material are respectively mounted on the outdoor side and the indoor side of the stud 20, and a heat insulating material made of glass wool is provided between the outer wall material and the inner wall material. Attach to form the outer wall.

Reference numeral 3 denotes a unit building. As shown in FIG. 2, the unit building 3 has nine building units 1 on the first floor.
This is a building in which four building units 2 are assembled on the second floor. 4 is a foundation, 5 is a folded metal roof material, and 51 is a roof material mounting bracket.

In the building unit 2 on the second floor, the ceiling beam and the floor beam are made of the same metal as the building unit 1 used on the first floor, but the ceiling beam and the floor beam are used. The number of beams may be smaller than the building unit 1.

Next, the construction method and operation of the unit building 3 will be described. At the factory, the skeleton of the building unit 1 as shown in FIG. 1 is manufactured. Similarly, the skeleton of the building unit 2 for the second floor is manufactured.

The ceiling structures of these building units 1 and 2 use a lip channel steel having a thickness of 0.6 mm as ceiling beams, so that these ceiling beams are hardly bent and have high mechanical strength. Moreover, since the ceiling beams have substantially parallel upper and lower surfaces, a ceiling material 15 is attached to the lower surface thereof by nailing, and a plate material 1 for a working plate (for a scaffold plate) is provided on the upper surface.
6 is easily attached by nailing.

The floor structure also has a floor joist having a thickness of 0.
Since a metal cylinder having a square cross section with an opening on one side of 6 mm is used, it is difficult to bend, has high mechanical strength, and can easily attach a floor material to the floor joist by nailing.

Therefore, the building units 1 and 2 are completed by attaching inner walls, outer walls and the like to the building units 1 and 2 and finishing them, and installing equipment furniture and the like.

Nine building units 1 and four building units 2 manufactured as described above are transported to the construction site. Then, at the construction site, as shown in FIG. 2, nine building units 1 are installed on a foundation 4 provided in advance to form a first floor portion, and four building units 2 are installed thereon.
Next, the roofing material mounting bracket 51 is attached to the roof, and the roofing material 5 is fitted onto the roofing material mounting bracket 51 to attach the roofing material 5. Further, finishing such as installation of water and sewage is completed to complete the unit building 3. These roofing materials 5
Installation work and plumbing work to install water and sewage,
This is convenient because a person can work on the plate 16 of the ceiling structure.

In the unit building 3 completed in this way, the ceiling structures of the building units 1 and 2 have a thickness of 0.6 m.
Since the m lip channel steel is used as the ceiling beam, the ceiling beam is unlikely to bend and has high mechanical strength. Further, the floor structure of the building unit 1 is such that a plurality of metal floor beams 15 are bridged substantially in parallel on a pair of opposed floor beams 13 framed in a rectangular shape. Since the floor joist 16 made of a long body formed by shaping a steel plate having a thickness of 0.6 mm into a rectangular cross section with one side opened, that is, having a shape having substantially parallel upper and lower surfaces is attached, the bending of the floor joist 16 is reduced. Small and high mechanical strength.

(Embodiment 2) FIG. 3 shows another embodiment of the present invention. FIG. 3 (a) is a sectional view showing a portion corresponding to the portion shown in FIG. () Is a perspective view showing a state before the plate 16 is attached.

The second embodiment differs from the first embodiment shown in FIGS. 1 and 2 in the mounting structure of the plate 16 to the ceiling beam 14. Since other structures are the same as those of the first embodiment, the same parts as those of the first embodiment shown in FIGS.

That is, the plate member 16a is a particle board having the same thickness of 12 mm and a width of 450 mm as the plate member 16 of the first embodiment, and is attached by nailing to the ceiling beam 14 via a wooden brick 21 which is a non-metallic body. This is different from the first embodiment.

As described above, since the plate member 16a is attached via the wooden brick 21 without directly touching the metal ceiling beam 14, the metal ceiling beam 14 does not become a cold bridge (thermal bridge). Inconvenience such as dew condensation does not occur in that part.

(Embodiment 3) FIG. 4 shows still another embodiment of the present invention, and is a cross-sectional view showing a portion corresponding to the portion shown in FIG.

The third embodiment differs from the first embodiment shown in FIGS. 1 and 2 in that a heat insulating material 22 is laid on the ceiling material 15. Since other structures are the same as those of the first embodiment, the same parts as those of the first embodiment shown in FIGS.

That is, a heat insulating material 22 made of glass wool is laid on the ceiling material 15 at a height reaching the lower surface of the plate material 16 mounted on the ceiling beam 14. Because of the heat insulation, the metal ceiling beam 1
4 is to eliminate the poor insulation caused by the cold bridge (thermal bridge). Note that, as in Embodiment 2 shown in FIG. 3, the plate 16 may be attached to the ceiling beam 14 via the wooden brick 21.

(Embodiment 4) FIG. 5 shows still another embodiment of the present invention. (A) is a sectional view showing a portion corresponding to the portion shown in FIG. 1 (B) of Embodiment 1. (B) is a CC cross-sectional view of (a).

The fourth embodiment is different from the first embodiment shown in FIGS. 1 and 2 in that a heat insulating material 23 is laid on a plate 16. Since other structures are the same as those of the first embodiment, the same parts as those of the first embodiment shown in FIGS.

That is, the heat insulating material 23 made of glass wool is laid on the plate material 16. Since the heat insulating material 23 is used for the heat insulating material 23, the heat insulation failure due to the cold bridge (thermal bridge) due to the metal ceiling beam 14. Is to eliminate. The heat insulating material 23 may be laid in advance at a factory or the like, or the heat insulating material 23 is not laid, and
After using 6 as a scaffold board (working board), the heat insulating material 23 may be laid. In addition, as in Embodiment 2 shown in FIG.
The plate 16 may be attached to the ceiling beam 14 via the wooden brick 21. Also, as in the third embodiment, the ceiling material 1
A heat insulating material such as glass wool may be laid on 5. Further, as shown in FIG.
Although it is laid over the entire upper surface of the plate material 16, it may be partially laid only at a portion where the ceiling beam 14 is present.

(Embodiment 5) FIG. 6 shows still another embodiment of the present invention, and is a cross-sectional view showing a portion corresponding to the portion shown in FIG.

The fifth embodiment is different from the fourth embodiment shown in FIG. 5 in that the heat insulating material laid on the plate 16 mounted on the ceiling beam 14 is a hard heat insulating material. Since other structures are the same as those of the first embodiment, the same parts as those of the fourth embodiment shown in FIG.

That is, a hard heat insulating material 24 made of a hard urethane foam plate is laid on the plate 16.
The rigid heat insulating material 24 eliminates poor heat insulation due to the cold bridge (thermal bridge) due to the metal ceiling beams 14, and allows a person to ride on it, and is used as a scaffold plate (working plate) as it is. You can do it.

As in Embodiment 2 shown in FIG. 3, the plate 16 may be attached to the ceiling beam 14 via the wooden brick 21. Further, similarly to the third embodiment, a heat insulating material such as glass wool may be laid on the ceiling material 15. Further, as in the third embodiment, the hard heat insulating material 24 may be partially laid only in a portion where the ceiling beam 14 is located.

[0062]

According to the first aspect of the present invention, since the ceiling beam is made of shaped steel, the ceiling beam is difficult to bend, and the ceiling beam can be installed without reducing the distance between the ceiling beams. It becomes easy and the distance between the floor and the ceiling can be increased because the height of the ceiling beam is not increased. In addition, since wood is not used for the ceiling beam, a fire-resistant ceiling structure can be used. Becomes

Further, since a plate is mounted on the ceiling beam, the plate can be used as a scaffolding plate or a work plate for construction work such as wiring and piping when the building is constructed. When a floor structure on an upper floor is placed on the floor, it can be used as a support base for supporting an underfloor storage.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, the plate is mounted on the ceiling beam with a non-metallic body, and does not directly contact the channel steel. Therefore, the channel steel is prevented from becoming a cold bridge (hot bridge), and the heat insulating performance is not reduced, and there is no dew condensation at that portion.

The ceiling beam has a thickness of 0.5-1.
When a long body formed of a specific steel plate such as 0 mm is used as a ceiling beam, the ceiling beam is difficult to bend, the mechanical strength is large, and the ceiling material and plate material are nailed to this ceiling beam. Can be attached.

According to the third aspect of the present invention, since the heat insulating material is filled between the ceiling material and the plate material so as to be in contact with the ceiling material and the plate material, the shaped steel is used as the ceiling beam by the heat insulating material. This prevents a decrease in heat insulation.

According to the fourth aspect of the present invention, since the heat insulating material is laid on the plate material, the heat insulating material prevents a decrease in the heat insulating property due to the use of the shape steel for the ceiling beam. If a hard heat insulating material is used as the heat insulating material laid on the plate, a person can ride on the heat insulating material, and the construction work of the building becomes easy.

In the invention according to claim 5, claim 1 is
Since the building unit is provided with the ceiling structure according to any one of claims 1 to 4, the ceiling structure is the same as the ceiling structure of the invention according to claims 1 to 4. Therefore, the bending of the ceiling beam is small and the mechanical strength is large.

Further, the plate material on the ceiling beam can be used as a scaffold plate or a work plate at the time of assembling and constructing the building unit, and construction work such as wiring and piping can be performed. In addition, this plate material,
When a floor structure on the floor is placed on the ceiling structure, it can be used as a support base for supporting a storage unit under the floor.

According to the sixth aspect of the present invention, there is provided the first aspect.
Since the building is provided with the ceiling structure according to any one of the above-described items 4, a building having a ceiling with small bending of the ceiling beam and high mechanical strength is constructed. .

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, wherein (a) is an explanatory view showing a skeleton of a building unit, and (b) is an A- of (a).
A sectional view, (C) is an explanatory view showing an enlarged B portion of (A), and (D) is a perspective view of a ceiling beam.

FIGS. 2A and 2B show a state in which a unit building is assembled, (A) is an explanatory view showing a foundation state, (B) is an explanatory view showing a state in which a building unit is assembled, and (C) is a roofing material. (D) is an explanatory view showing a completed unit building.

3A and 3B show another embodiment of the present invention, wherein FIG. 3A is a cross-sectional view showing a portion corresponding to the portion shown in FIG.
(B) is a perspective view showing a state before a plate material is attached.

FIG. 4 shows still another embodiment of the present invention.
It is sectional drawing which shows the location corresponding to the part shown in (b).

FIG. 5 shows yet another embodiment of the present invention.
(A) is a sectional view showing a portion corresponding to the portion shown in FIG. 1 (B), and (B) is a CC sectional view of (A).

FIG. 6 shows still another embodiment of the present invention.
It is sectional drawing which shows the part corresponding to the part shown to (a).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1, 2 Building unit 3 Unit building 11 Column 12 Ceiling beam 13 Floor beam 14 Ceiling beam 15 Ceiling material 16 Plate material 17 Floor beam 21 Wood brick 22, 23 Insulation material (glass wool) 24 Hard insulation material (hard urethane foam)

Claims (6)

[Claims] 1. A ceiling structure in which a ceiling material is attached below a ceiling beam, wherein said ceiling beam is made of shaped steel. A ceiling structure characterized by attaching a plate material on top. 2. A ceiling structure in which a ceiling material is attached below a ceiling beam, wherein said ceiling beam is made of shaped steel. A ceiling structure wherein a plate material is attached via a non-metallic body thereon. 3. The ceiling structure according to claim 1, wherein a heat insulating material is laid on the ceiling material at a height in contact with a lower surface of the plate material. 4. The ceiling structure according to claim 1, wherein a heat insulating material is laid on the plate material. 5. A building unit comprising the ceiling structure according to claim 1. Description: 6. A building provided with the ceiling structure according to claim 1. Description: