JP7650175B2 - Underfloor waterproof structure - Google Patents

Description

This invention relates to a water-stopping structure for preventing water from entering under the floor of a building.

Patent Document 1 discloses a structure in which a foundation drain is arranged opposite the outer lower end of an exterior wall panel of a building, and the gap between the lower end of this drain and the slab footing is sealed with a sealing member. With this structure, it is possible to prevent flooding under the floor caused by the water level exceeding the rising part of the slab footing. It also states that flooding under the floor caused by water seeping around from the ground below the slab footing can be prevented by covering the entire ground under the floor with a concrete floor.

JP 2013-199755 A

However, the above structure is simply a structure with a concrete floor, and there is a risk that water may seep in from the boundary between the base of the slab and the concrete floor due to the water pressure underneath the concrete floor. In particular, the risk of water seepage increases as the concrete floor shrinks over time.

This invention provides an underfloor water-stopping structure that can prevent water that has seeped under the base of a slab from seeping through the boundary between the base and the concrete floor and onto the concrete floor.

The underfloor water-stopping structure of this invention is characterized in that the upper surface of the base of the continuous foundation of a building is overlapped and in contact with the peripheral portion of the concrete floor under the floor of the building, and a water-stopping material is provided between the upper surface of the base and the lower surface of the peripheral portion of the concrete floor at the overlapping point.

With the above configuration, water that has penetrated under the base of the slab and into the concrete floor cannot pass through the boundary between the base and the concrete floor due to the water-stopping material, preventing water from seeping onto the concrete floor.

The water-stopping material may be made of a clay material that expands when it absorbs water. In this way, even if the concrete floor loses weight over time, the water-stopping material will expand when it absorbs water during floods, etc., making it less likely for gaps to form, thereby improving water ingress prevention performance.

The concrete floor may contain reinforcing bars. In this way, even if the water-stopping material leaves no place for the rising water pressure to escape under the concrete floor, the concrete floor containing reinforcing bars can withstand large forces and therefore can be prevented from being damaged. Even in cases where reinforcing bars are not required in the concrete floor due to the hardness of the ground, reinforcing bars are installed to prevent the concrete floor from being destroyed by rising water pressure.

A connecting member may protrude from the base of the slab, and the reinforcing bars may be connected to the connecting member to integrate the concrete floor with the base of the slab. In this way, even if the concrete floor tries to rise as a whole without being destroyed by an increase in water pressure, the force is received by the slab, preventing the concrete floor from rising. In other words, it is possible to prevent the concrete floor from rising due to an increase in water pressure acting on the concrete floor, causing a gap to form between the base and the concrete floor.

The concrete floor has a recess that is recessed toward the interior of the building, and an opening for inserting a pipe is formed in the rising part of the slab located near this recess, and the opening may be equipped with a pipe water-stopping material that prevents water from seeping in through the opening. This allows the pipe to be inserted into the rising part of the slab, and prevents water from seeping in around the pipe and into the floor below.

The base of the slab may have a convex portion that protrudes toward the interior so as to overlap with the surrounding area of the concave portion of the concrete floor. This allows the water-stopping material to be appropriately positioned at the convex portion.

While a moisture-proof sheet is laid underneath the concrete floor, it is preferable that the moisture-proof sheet is not laid in the area where the water-stopping material is located. This makes it possible to avoid the water-stopping function of the water-stopping material being reduced by the presence of the moisture-proof sheet.

This invention has the effect of preventing water from seeping into the concrete floor from between the base of the slab and the concrete floor due to an increase in water pressure below the concrete floor.

FIG. 2 is an explanatory diagram showing an underfloor water stopping structure according to an embodiment. FIG. 4 is an explanatory diagram of underfloor water intrusion prevention in an embodiment. 2 is an explanatory diagram showing an example of a general manufacturing process for the underfloor waterproofing structure of FIG. 1. FIG. 4 is an explanatory diagram showing an example of a process continued from FIG. 3 . FIG. 11 is an explanatory diagram showing an underfloor water stopping structure according to another embodiment. FIG. 11 is an explanatory diagram showing an underfloor water stopping structure according to another embodiment.

(Embodiment 1)
Hereinafter, an embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings.
1 and 2, in the underfloor water stop structure 100 according to the embodiment, the peripheral portion of the concrete floor 2 under the floor of the building overlaps and contacts the upper surface side of the base portion 11 of the continuous footing 1 of the building, and a water stop material 3 is provided between the upper surface of the base portion 11 at this overlapping point (joint point) and the lower surface of the peripheral portion of the concrete floor 2. More specifically, the concrete floor 2 is applied within a closed area surrounded by the continuous footing 1 on the periphery of the building, and the water stop material 3 exists in an uninterrupted ring shape within the closed area.

The height of the rising part 12 of the slab 1 is set to, for example, 750 mm, which is 450 mm higher than the 300 mm specified in the notification, and is designed to prevent water from overflowing the slab 1 and seeping under the floor as much as possible. The height of the rising part 12 of the slab 1 is not limited to the above 750 mm.

The water-stopping material 3 may be made of an elastic material such as rubber, but in this embodiment, it is made of a clay material (such as Kuniseal, which is a product name) that expands when it absorbs moisture, and is processed into a strip shape, for example. The water-stopping material 3 is attached in a strip shape to the upper surface part, for example, 40 mm to 100 mm away from the edge of the base part 11 of the strip footing 1. In this embodiment, the water-stopping material 3 is attached 50 mm away from the edge of the base part 11 of the strip footing 1. If the connecting member 11a described later is not installed, the water-stopping material 3 may be placed at the corner of the base part 11 and the rising part 12.

The concrete floor 2 contains reinforcing bars. Under the concrete floor 2, the soil is returned to approximately the top surface of the base portion 11, and the reinforcing bars are assembled on top of this soil and concrete is poured to create the concrete floor 2. The thickness of this concrete floor is, for example, 120 mm to 300 mm (a typical concrete floor is about 60 mm thick).

In addition, in this embodiment, multiple connecting members 11a protrude at a predetermined interval from the base portion 11 of the slab 1, and the rebars of the concrete floor 2 are connected to the connecting members 11a. As a result, the concrete for the floor is positioned so as to cover the connecting members 11a, and the concrete hardens to integrate the concrete floor 2 with the base portion 11 of the slab 1.

The connecting member 11a is, for example, made of a reinforcing bar in a roughly Z-shape. The upper half of the vertical rod-shaped portion of the connecting member 11a in the Z-shape protrudes above the base portion 11, and the tip of the upper horizontal rod-shaped portion on the upper side is positioned facing the indoor side. The lower horizontal rod-shaped portion on the lower side of the connecting member 11a is connected to a reinforcing bar inside the base portion 11 and fixed to the base portion 11. The Z-shaped vertical rod-shaped portion and the lower horizontal rod-shaped portion are located on the outdoor side of the water-stopping material 3 located on the side edge of the base portion 11, and the upper horizontal rod-shaped portion of the connecting member 11a is located above the water-stopping material 3.

The concrete floor 2 has a recess 21 recessed toward the interior of the building. An opening 12a for inserting the pipe 4 is formed in the lower part (below ground level) of the rising part 12 of the slab 1 located near the recess 21. A pipe water stop material 5 is provided between the opening 12a and the outer periphery of the pipe 4 passed through the opening 12a. The pipe water stop material 5 is a clay material that expands when it absorbs moisture, a sealing material, or a packing made of rubber or the like. The opening 12a can be formed using equipment pipe paper void. The product name Eco Sleeve DAM can be used for pipe water stop using a packing.

In addition, the base part 11 of the slab footing is formed with a convex part 11b that protrudes indoors so as to overlap with the indoor side area of the surrounding area of the concave part 21 of the concrete floor 2, and a water-stopping material 3 is attached to the upper surface of this convex part 11b. In other words, the overlapping contact between the base part 11 and the concrete floor 2 is ensured so as to bypass the concave part 21 of the concrete floor 2, and the water-stopping material 3 is attached to this contact area.

In addition, a moisture-proof sheet (not shown) is laid under the concrete floor 2. However, this moisture-proof sheet is not laid where the water-stopping material 3 is located. In other words, the moisture-proof sheet is not present between the water-stopping material 3 and the concrete floor 2, or at the boundary between the water-stopping material 3 and the base portion 11.

An example of construction of the underfloor water stop structure 100 according to the above embodiment is described below. As shown in FIG. 3, a slab 1 is constructed at the construction site of a building. At this time, the pipe member is fixed to the reinforcing bars of the rising part 12 of the slab 1 with clips or the like, and an opening 12a is created by pouring concrete into the slab formwork. In addition, the lower side of the connecting member 11a is fastened to the reinforcing bars of the base part 11.

Once the slab 1 is completed, the waterproofing material 3 is pressed against and attached to the upper surface of the edge of the base 11 of the slab 1 before the concrete floor 2 is poured. Furthermore, as shown in FIG. 4, a formwork F is installed on the base 11 for creating the recessed area 21 of the concrete floor 2. The rebars for the concrete floor 2 are assembled on the soil next to the base 11, and the upper horizontal rod-shaped portion of the Z-shape of the connecting member 11a is attached to the rebars. The concrete for the floor is then poured to cover the rebars and the base 11, and the concrete floor 2 is created.

With the above configuration, water that has penetrated under the base 11 of the slab 1 and into the underside of the concrete floor 2 is prevented from passing through the boundary between the base 11 and the concrete floor 2 by the water-stopping material 3, and water seepage onto the concrete floor 2 can be suppressed.

If the water-stopping material 3 is made of a clay-like material that expands when it absorbs water, even if the concrete floor 2 loses weight over time, the water-stopping material 3 will expand when it absorbs water in the event of a flood or other event, sealing the gaps and improving the water ingress prevention performance. Note that the water-stopping material 3 is not limited to being made of the clay-like material.

If the concrete floor 2 contains reinforcing bars, even if the water-stopping material 3 prevents the rising water pressure from escaping under the concrete floor 2, the concrete floor 2 containing reinforcing bars can withstand large forces, preventing damage to the concrete floor 2. Even if reinforcing bars are not required in the concrete floor due to the hardness of the ground, the reinforcing bars are installed to prevent damage to the concrete floor 2 due to rising water pressure.

When the concrete floor 2 is integrated with the base part 11 of the slab 1 by connecting the rebars of the concrete floor 2 to the connecting member 11a protruding from the base part 11 of the slab 1, even if the concrete floor 2 tries to rise as a whole without being destroyed by an increase in water pressure, the slab 1 absorbs this force, preventing the concrete floor 2 from rising. In other words, it is possible to prevent the concrete floor 2 from rising due to an increase in water pressure on the concrete floor 2, causing a gap to form between the base part 11 and the concrete floor 2.

In addition, by providing a pipe water-stopping material 5 at the opening 12a formed in the rising portion 12, water intrusion from around the pipes is also suppressed.

In addition, if a convex portion 11b is formed on the base portion 11 of the slab foundation at a position that overlaps with the surrounding area of the concave portion 21 of the concrete floor 2, the water-stopping material 3 can be appropriately positioned on the convex portion 11b.

If the moisture-proof sheet is not placed in the area where the water-stopping material 3 is located, the water-stopping function of the water-stopping material 3 can be prevented from being reduced by the moisture-proof sheet.

As shown in FIG. 5, it is possible to make the concrete floor 2 thicker and increase the weight per unit area of the concrete floor 2 without providing the connecting member 11a, thereby making the concrete floor 2 not float up due to water pressure. In other words, the concrete floor 2 may not be integrated with the base 11 of the strip footing 1. If the thickness of the concrete floor 2 is at least about 1/2.3 of the flood height from the top surface of the base 11 of the strip footing, it is believed that the concrete floor 2 will not float up due to an increase in water pressure below the floor.

In addition, the structure is not limited to having the above-mentioned convex portion 11b. As shown in FIG. 6, if the width of the base portion 11 that extends into the indoor side is sufficiently large compared to the length of the recessed portion 21 that extends into the indoor side, the structure may be one that does not have the above-mentioned convex portion 11b.

Although an embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the illustrated embodiment. Various modifications and variations can be made to the illustrated embodiment within the same scope as the present invention or within an equivalent scope.

1: Spread foundation 2: Concrete floor 3: Water stop material 4: Pipe 5: Pipe water stop material 11: Base portion 11a: Connecting member 11b: Convex portion 12: Rising portion 12a: Opening 21: Concave portion 100: Underfloor water stop structure

Claims (7)

An underfloor water-stopping structure characterized in that the upper surface of the base part of a building's strip foundation is overlapped and in contact with the peripheral portion of the concrete floor under the floor of the building, a water-stopping material is provided between the upper surface of the base part and the underside of the peripheral portion of the concrete floor at the overlapping point, and the structure prevents the concrete floor from lifting due to water pressure from the underside of the concrete floor, causing a gap to form between the upper surface of the base part and the underside of the peripheral portion of the concrete floor . The underfloor water stop structure according to claim 1, characterized in that the water stop material is made of a clay-based material that expands when it absorbs moisture. The underfloor water stop structure according to claim 1 or 2, characterized in that the concrete floor is reinforced with steel. In the underfloor water-stopping structure described in claim 3, the reinforcing bars are connected to connecting members protruding from the base portion of the strip footing, and the concrete floor is integrated with the base portion of the strip footing, thereby preventing the occurrence of gaps between the upper surface of the base portion and the underside of the peripheral portion of the concrete floor . An underfloor water-stopping structure characterized in that the upper surface of the base part of a building's strip footing is overlapped and in contact with the peripheral portion of the concrete floor under the floor of the building, and a water-stopping material is provided between the upper surface of the base part and the underside of the peripheral portion of the concrete floor at this overlapping point , a recess that is recessed toward the interior of the building is formed in the concrete floor, an opening for inserting piping is formed in the rising part of the strip footing located near this recessed point, and the opening is provided with a water-stopping material for piping to prevent water from seeping in through the opening. The underfloor water stop structure according to claim 5, characterized in that the base of the slab is formed with a convex portion that protrudes toward the interior so as to overlap with the surrounding area of the concave portion of the concrete floor. The underfloor water stop structure according to any one of claims 1 to 6, characterized in that a moisture-proof sheet is laid under the concrete floor, but the moisture-proof sheet is not laid in the area where the water-stop material is located.

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