JP7583582B2 - Foundation penetration structure for piping and construction method for foundation penetration piping - Google Patents

Description

This invention relates to a foundation penetration structure for piping and a method for constructing foundation penetration piping.

Buildings such as houses are equipped with various types of piping, such as water supply pipes and drainage pipes. These pipes are installed so as to penetrate between the inside and outside of the foundation that supports the building on the ground (see, for example, Patent Document 1).

A through hole is formed in the foundation, and the pipe is inserted through the through hole. A water-stopping material is then placed in the gap between the through hole and the pipe, and the water is stopped by the water-stopping material. In this way, the pipe becomes a foundation-penetrating pipe.

JP 2018-151038 A

When installing an expansive water-stopping material in the gap between the foundation's through-hole and the pipe, a clamp is required to prevent the water-stopping material from expanding from both the indoor and outdoor sides. Furthermore, when the work of passing the pipe through the through-hole (foundation penetration work) is performed, for example, after the building has been installed on the foundation, the work to install the clamp on the indoor side requires getting under the floor of the building, which makes it difficult to work.

Therefore, the main objective of the present invention is to contribute to improving the above-mentioned problems.

In response to the above problems, the present invention provides:
A water-swelling water-stopping material is installed in a circumferential direction in a gap between a through-hole portion formed in a foundation of a building and a pipe inserted through the through-hole portion,
A foam material is provided at a position inside the gap on the indoor side of the water-stopping material,
In the gap, at a position on the outdoor side of the water-stopping material, mortar is poured so as to be approximately flush with the outdoor surface of the foundation, forming three layers .
The foam material and the mortar sandwich and press the water-stopping material from both sides,
The water-swellable water-stopping material is characterized by a foundation penetration structure for piping in which expansion in the longitudinal direction is suppressed and expansion in the radial direction is allowed.

According to the present invention, the foam material, the water-expandable water-stopping material, and the mortar are arranged in three layers from the indoor side to the outdoor side, and the workability of holding down the indoor side of the water-stopping material can be improved. In addition, the foam material and the mortar sandwich and hold down the water-expandable water-stopping material from both sides inside the gap, suppressing the water-expandable water-stopping material from expanding in the longitudinal direction and expanding it in the radial direction. The surface of the foundation can be smoothed by pouring the mortar almost flush with the outdoor surface of the foundation.

FIG. 2 is a vertical cross-sectional view of the foundation penetration structure for piping according to the present embodiment. FIG. 2 is a perspective view showing a foam material with a circular cross section. FIG. 2 is a perspective view showing a foam material with a rectangular cross section. 2 is a diagram showing a state in which a pipe with a foam material attached is inserted into a through hole of the foundation of FIG. 1 from the outdoor side. 2 is a diagram showing a state in which a water-stopping material is applied from the outdoor side into a gap between a through hole portion and a pipe in FIG. 1 . FIG. FIG. 2 is a diagram showing the state in which mortar is poured into the gap in FIG. 1 from the outdoor side. FIG. 2 is a vertical cross-sectional view of a foundation penetration structure for piping according to a comparative example. 6 is a diagram showing a state in which a backup jig is inserted from the indoor side into a gap between the through hole portion and the pipe in FIG. 5 . FIG. 6 is a diagram showing a state in which a water-stopping material is applied from the outdoor side into a gap between the through hole portion of FIG. 5 and the pipe. FIG. FIG. 6 is a diagram showing the state in which mortar is poured into the gap of FIG. 5 from both the indoor side and the outdoor side.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
1 to 8 are diagrams for explaining this embodiment, with Figs. 1 to 4 showing an example and Figs. 5 to 8 showing comparative examples.

<Configuration> The configuration of this embodiment is explained below.

As shown in FIG. 1, various types of pipes 2, such as water supply pipes and drainage pipes, are installed in a building 1, such as a house. These pipes 2 are installed so as to penetrate between the inside and outside of a foundation 4 that supports the building 1 on the ground GL. In this way, the pipes 2 become foundation-penetrating pipes.

The building 1 may be of any structure. The building 1 may be, for example, a unit building. A unit building is a building 1 that can be constructed in a short period of time by transporting building units that have been manufactured in advance in a factory to a construction site and assembling them there. The building units are assembled so that they can be installed on top of the foundations 4.

The water supply pipe is a pipe that supplies cold water and hot water to building 1. The drainage pipe is a pipe that directs wastewater generated in building 1 to an external sewer system, etc. The ground level is the site on which building 1 is to be constructed.

The foundation 4 is a reinforced concrete structure that is placed on the ground GL and supports the lower part of the building 1 at a position higher than the ground GL. There are two types of foundations 4: a strip foundation and a slab foundation. A strip foundation is mainly composed of a rising part 5 that rises from the ground GL. A slab foundation is mainly composed of the rising part 5 and a horizontal, flat slab part 6 that covers the ground GL inside the rising part 5. The foundation 4 may be either a strip foundation or a slab foundation. In this embodiment, the foundation 4 is a slab foundation.

In addition to the basic configuration described above, this embodiment can have the following configuration:

(1) In the foundation penetration structure of the piping 2 of this embodiment, a water-stopping material 13 is installed circumferentially in the gap 12 between the through hole portion 11 formed in the foundation 4 and the piping 2 inserted into the through hole portion 11.
A foam material 16 is installed at a position inside the gap 12 on the indoor side 15 of the water-stopping material 13.
Mortar 18 is poured at a position 17 on the outdoor side of the water-stopping material 13 in the gap 12.

Here, the through hole portion 11 is a hole that penetrates between the inside and outside of the foundation 4. The through hole portion 11 may be provided so as to penetrate the rising portion 5 of the foundation 4, may be provided so as to penetrate the slab portion 6, or may be provided so as to penetrate between the rising portion 5 and the slab portion 6. The through hole portion 11 may be provided almost horizontally, or may be provided at an incline. When the through hole portion 11 is inclined, it is preferable to install it so that the indoor side 15 is higher and the outdoor side 17 is lower. In this embodiment, the through hole portion 11 penetrates the rising portion 5 at a position higher than the ground GL almost horizontally.

The through hole 11 is formed, for example, by burying a pipe member 21 in the foundation 4 when the foundation 4 is poured.

The pipe member 21 may be a void pipe made of paper or flexible resin, or may be a resin pipe, but in order to prevent the through hole portion 11 from deforming, it is preferable to use a hard resin pipe such as a PVC pipe having the required thickness and strength for the pipe member 21. In the case of a void pipe, the void pipe can be removed from the foundation 4 after the foundation 4 is poured. In the case of a hard resin pipe, the resin pipe is left in the foundation 4 even after the foundation 4 is poured. As a result, the internal space of the pipe member 21 becomes the through hole portion 11.

It is preferable that the through hole 11 be linear and of uniform diameter. In this embodiment, the through hole 11 is formed by embedding a single straight pipe member 21 (e.g., a cylindrical PVC pipe) made of hard resin and having the same length as the thickness of the rising portion 5 within the rising portion 5. The pipe member 21 is embedded in the foundation 4 so that it is approximately horizontal, with both ends approximately flush with both sides of the rising portion 5, and approximately perpendicular to the rising portion 5.

The pipe 2 is a tubular member that passes through the inside of the through hole 11, and can be, for example, a water supply pipe or a drain pipe as described above. The pipe 2 can also be, for example, a heat medium supply and exhaust pipe such as a refrigerant pipe or a heat medium pipe. It is preferable that at least the portion of the pipe 2 that passes through the through hole 11 is straight and of uniform diameter. For this reason, it is preferable that the pipe 2 has a cross-sectional shape similar to that of the through hole 11, but is at least one size smaller than the through hole 11. In this embodiment, the pipe 2 is a cylindrical pipe.

The gap 12 is a gap formed between the through hole portion 11 (its inner peripheral surface) and the pipe 2 (its outer peripheral surface). In this embodiment, the through hole portion 11 and the pipe 2 each have a circular cross section, so that an annular gap 12 is formed between the through hole portion 11 and the pipe 2. It is preferable that the gap 12 is of a substantially uniform size in the circumferential direction. In order to make the gap 12 substantially uniform in the circumferential direction, it is preferable to apply the water-stopping material 13, the foam material 16, and the mortar 18 before the pipe 2 is completely fixed. This is because if the pipe 2 is completely fixed, there is a high possibility that the gap 12 will not be uniform in the circumferential direction.

The water-stopping material 13 is a member for sealing the through-hole portion 11 to prevent, for example, rainwater from entering the indoor side 15 from the outdoor side 17. Any water-stopping material 13 may be used, but it is preferable to use an expandable material in order to improve the sealing performance for the gap 12. For the expandable water-stopping material 13, for example, a water-expandable clay sealant using clay such as bentonite can be used. For the water-stopping material 13, a string-shaped material is cut to the extent that an optimal filling amount is obtained. The string-shaped water-stopping material 13 is used with an optimal length and a thickness optimally selected according to the inner diameter of the through-hole portion 11, the outer diameter of the pipe 2, the size of the gap 12, and the circumference of the gap 12. In addition to the above, the expandable water-stopping material 13 can be, for example, a caulking-type water-expandable one-component sealant, which can be injected into the gap 12.

The water-stopping material 13 is installed at the middle of the gap 12 between the through hole 11 and the pipe 2 in the longitudinal direction (axial direction of the through hole 11). The expansive water-stopping material 13 expands after installation, so both sides of the water-stopping material 13 need to be held down. Therefore, the water-stopping material 13 is installed in a position such that a portion (space) for placing the foam material 16 and mortar 18 that serve as a hold-down is left on both sides of the water-stopping material 13 (indoor side 15 and outdoor side 17). Even in the case of a non-expansive water-stopping material 13, it is expected that the sealing properties of the water-stopping material 13 can be improved by pressing and compressing the water-stopping material 13 from both sides.

The circumferential direction refers to the direction that goes around the inner surface of the through hole portion 11 and the outer surface of the pipe 2.

The indoor side 15 refers to the inside of the building 1. The indoor side 15 from the water-stopping material 13 refers to the part on the right side in the figure from the water-stopping material 13 to the opening of the through-hole portion 11 on the indoor side 15.

The foam material 16 is a material that is light, flexible, and capable of elastic deformation due to the inclusion of many air bubbles inside. The foam material 16 can be used in the form of a ring-shaped elongated string-like material that has the same length as the circumference of the gap 12 and a uniform thickness that is the same as or slightly larger than the size of the gap 12. The foam material 16 is accurately installed in the gap 12 at a position on the indoor side 15 rather than the installation position of the water-stopping material 13.

The foam material 16 is preferably a member with a uniform cross section, such as a circular cross section as shown in FIG. 1A or a rectangular cross section as shown in FIG. 1B. In this embodiment, the foam material 16 is a string-like member of an optimal thickness made of a material such as silicone foam 16a or urethane foam 16b, which is cut to an optimal length and rolled into a ring shape. The foam material 16 may be one that is already in a ring shape from the beginning. The foam material 16 is left inside the gap 12 even after construction.

The outdoor side 17 refers to the outside of the building 1. The outdoor side 17 of the water-stopping material 13 refers to the portion on the left side of the figure from the water-stopping material 13 to the opening of the outdoor side 17 of the through-hole portion 11.

Mortar 18 is a fluid, hardening building material made by mixing sand (fine aggregate) and cement with water. Mortar 18 is filled into the portion of gap 12 that is on the outdoor side 17 of water-stopping material 13 so that it is flush with the outdoor side 17 surface of foundation 4.

(2) The foam material 16 may be attached to the outer peripheral surface of the pipe 2 and installed in the through hole portion 11 together with the pipe 2.

Here, the outer peripheral surface of the pipe 2 is the cylindrical surface exposed to the outside of the cylindrical pipe 2. The foam material 16 may be integrated with the pipe 2 by, for example, first gluing the end faces together to form a ring shape, fitting (outside fitting) the foam material 16 to the outer peripheral surface of the pipe 2, and then attaching the foam material 16 with an adhesive so that it does not move relative to the pipe 2.

The foam material 16 may also be integrated with the pipe 2 by wrapping it around the outer periphery of the pipe 2 in a ring shape and then gluing it with adhesive. In this case, the end faces of the foam material 16 wrapped around the outer periphery of the pipe 2 are later glued together with adhesive.

The foam material 16 can be, for example, the silicone foam 16a (or urethane foam 16b) described above.

As a result, the foam material 16 is inserted into the through-hole portion 11 together with the piping 2. Then, by inserting and arranging the piping 2 into the through-hole portion 11, the foam material 16 is inserted and installed in the gap 12. At this time, since the foam material 16 has a uniform thickness in the circumferential direction, the gap 12 can be blocked in a uniform manner in the circumferential direction.

The pipe 2 may be inserted into the through-hole portion 11 from the indoor side 15, or may be inserted into the through-hole portion 11 from the outdoor side 17. In this embodiment, the pipe 2 is inserted into the through-hole portion 11 from the indoor side 15.

(3) The foam material 16 may be attached to the outer surface of the pipe 2 with adhesive tape 25 (Figure 1B).

Here, the adhesive tape 25 is an adhesive fixing member formed by applying a layer of adhesive to the surface of a tape-like base material. For example, the foam material 16 may be integrated with the pipe 2 by applying an adhesive tape 25 such as double-sided tape to one side and wrapping the foam material 16 around the outer periphery of the pipe 2 with the side to which the double-sided tape is applied facing inward, and then attaching the adhesive side on the opposite side of the double-sided tape to the pipe 2. The foam material 16 may itself be made into the adhesive tape 25 by applying a layer of adhesive to one side. This allows the foam material 16 to be directly attached to the outer periphery of the pipe 2.

When attaching the foam material 16 to the pipe 2 with adhesive tape 25, the end faces of the foam material 16 attached to the outer periphery of the pipe 2 are later bonded together with adhesive tape 25 such as double-sided tape or adhesive. For example, the foam material 16 can be the above-mentioned urethane foam 16b (or silicone foam 16a).

(4) The following describes how to install foundation penetration piping.

The construction method for foundation penetration piping is as follows:
A foaming material 16 is attached to the outer peripheral surface of the pipe 2,
The pipe 2 having the foam material 16 attached to its outer peripheral surface is inserted into the through-hole portion 11 formed in the foundation 4, so that the foam material 16 is positioned inside the through-hole portion 11, and the gap 12 between the through-hole portion 11 and the pipe 2 is blocked in the circumferential direction by the foam material 16 (FIG. 2).
A waterproofing material 13 is placed in the gap 12 so as to be located on the outdoor side 17 of the foam material 16 (FIG. 3).
Mortar 18 may be poured on the outdoor side 17 of the water-stopping material 13 in the gap 12 (FIG. 4).

Here, the foundation penetration piping refers to the piping 2 that penetrates the foundation 4, as described above.

More specifically, in step 1 of the foundation penetration piping installation method, the inner diameter of the penetration hole 11 is first checked (inner diameter checking step).

In step 2, an optimal water-stopping material 13 is prepared by cutting a water-swelling clay sealant of an optimal thickness to an optimal length according to the inner diameter of the through-hole portion 11 and the outer diameter of the pipe 2. The water-stopping material 13 is soaked in water and moistened until the water-easily absorbent film on the surface dissolves (water-stopping material preparation step). Note that if the water-stopping material 13 is a caulking-type water-swelling one-component sealant, this water-stopping material preparation step is not necessary.

In step 3, the foam material 16 is attached in advance to the outer periphery of the pipe 2 outside the through-hole 11. The foam material 16 can be attached to the outer periphery of the pipe 2 by, for example, adhesive bonding or pasting with adhesive tape 25. Then, the pipe 2 with the foam material 16 attached is inserted into the through-hole 11 formed in the foundation 4 so that the foam material 16 is positioned at a predetermined position inside the through-hole 11. The pipe 2 can be inserted into the through-hole 11 from either the indoor side 15 or the outdoor side 17. However, in order to install the foam material 16 with good workability, it is preferable to insert it from the outdoor side 17 (installation step of the pipe 2 with foam material 16).

In step 4, the inside of the through hole 11 (the gap 12 between the through hole 11 and the pipe 2) is filled with the water-stopping material 13 from the outdoor side 17 (water-stopping material filling step). The water-stopping material 13 is filled from the position where it hits the foam material 16 to a position slightly behind the opening of the outdoor side 17 of the through hole 11 (for example, a position about 20 mm behind the opening). If the water-stopping material 13 is a caulking-type water-expandable one-component sealant, the water-stopping material 13 is injected into the gap 12 from the outdoor side 17. The water-stopping material 13 is applied with a finger, a long and thin tool, etc. so that the thickness (filling thickness) in the axial direction of the through hole 11 is secured to a required amount (for example, about 40 mm) or more, the thickness in the circumferential direction is uniform, and it fits the inner surface of the through hole 11 and the outer surface of the pipe 2. After the water-stopping material 13 is applied, its application status is checked at least at three or more positions that are approximately evenly spaced around the circumference (water-stopping material application status checking process).

In step 5, mortar 18 is filled into the opening on the outdoor side 17 of the through hole 11 (mortar filling step). To ensure and improve water-stopping performance, the mortar 18 is poked with an adjustment tool 31 such as a spatula to destroy any internal voids. The surface of the mortar 18 is adjusted so that it is flush with the surface of the outdoor side 17 of the through hole 11. The mortar 18 is made to have the required thickness in the axial direction (for example, about 20 mm). Note that the foam material 16 is left attached to the indoor side 15 of the through hole 11.

As a result of the above, the piping 2 (foundation penetration piping) that penetrates the foundation 4 is installed.

<Effects> This embodiment provides the following effects:

(Effects 1) The foundation penetration structure for the pipe 2 is such that the pipe 2 is inserted through the through hole 11 of the foundation 4, and a water-stopping material 13 is installed in the circumferential direction in the gap 12 between the through hole 11 and the pipe 2 inserted through the through hole 11. For example, a water-expanding clay sealant using clay such as bentonite, or a water-expanding one-component sealant of the caulking type is used as the water-stopping material 13. The expansive water-stopping material 13 needs to be pressed from both the indoor side 15 and the outdoor side 17 in order to ensure high sealing performance around the entire circumference of the gap 12 by suppressing expansion in the longitudinal direction and expanding appropriately in the radial direction.

In the existing foundation penetration structure of the pipe 2, as shown in the comparative examples of Figures 5 to 8, the indoor side 15 and outdoor side 17 of the water-stopping material 13 were both secured with mortar 18. Therefore, when performing the work of passing the pipe 2 through the foundation after the building 1 is installed (the work of passing the pipe 2 through the through hole portion 11 and fixing it), it becomes necessary to go under the floor of the building 1 and secure the indoor side 15 (applying mortar 18) from the indoor side 15, which makes it difficult to work.

When pouring mortar 18 to hold down the indoor side 15, the following work was carried out after inserting the pipe 2 into the through-hole 11. That is, first, as shown in FIG. 6, a backup jig 52 is inserted into the gap 12 between the through-hole 11 and the pipe 2 from the indoor side 15 to the position 51 where the water-stopping material 13 is to be installed. A jig 53 such as a ruler is inserted into the gap 12 from the outdoor side 17 to measure whether the backup jig 52 is correctly inserted to the above-mentioned position 51.

Next, as shown in FIG. 7, the water-stopping material 13 is installed in the gap 12 from the outdoor side 17 so that it abuts against the backup jig 52. After the water-stopping material 13 is installed in the gap 12, the backup jig 52 is removed from the gap 12 to the indoor side 15. Mortar 18 is then poured into the gap 12 from both the indoor side 15 and the outdoor side 17. For this reason, when performing foundation penetration work after the installation of the building 1, the construction requires a great deal of work.

In contrast, in this embodiment, the foam material 16 is placed in the gap 12 at a position closer to the indoor side 15 than the water-stopping material 13, and the mortar 18 is poured in the gap 12 at a position closer to the outdoor side 17 than the water-stopping material 13. This makes it possible to compress the water-stopping material 13 placed in the gap 12 by pressing it down from both sides with the foam material 16 on the indoor side 15 and the mortar 18 on the outdoor side 17, or to suppress the expansion of the expansive water-stopping material 13.

A foam material 16 is used to hold down the indoor side 15 of the water-stopping material 13. The foam material 16 is flexible and elastically deformable due to the air bubbles contained within it, so the elastic force of the foam material 16 can effectively suppress the expansion of the water-stopping material 13 towards the indoor side 15. The foam material 16 is also easy to install at the indoor side 15 position within the gap 12. For example, the foam material 16 can be installed at an optimal position within the gap 12 simply by inserting it into the through hole 11 together with the piping 2. The foam material 16 can be inserted and installed into the through hole 11 from either the indoor side 15 or the outdoor side 17 by performing the insertion and installation together with the piping 2.

Therefore, even when the work of penetrating the pipes 2 into the foundation is performed after the building 1 is installed, there is no need to perform work such as going under the floor of the building 1 to hold down the indoor side 15 and installing the foam material 16 alone in the gap 12 from the indoor side 15, which improves workability.

In addition, by using mortar 18 to secure the exterior side 17, the mortar 18 can be painted in the same way as the foundation 4. By applying the same paint to the mortar 18 as the foundation 4, the mortar 18 and the foundation 4 cannot be distinguished from each other, ensuring and improving the appearance quality of the foundation 4.

(Effect 2) The foundation penetration structure for the pipe 2 may be installed in the through-hole portion 11 together with the pipe 2 with the foam material 16 attached to the outer peripheral surface of the pipe 2. This allows the foam material 16 to be easily and reliably installed in the gap 12 from the outdoor side 17 simply by inserting the pipe 2, which is integrated with the foam material 16 attached to its outer peripheral surface, into the through-hole portion 11 from the outdoor side 17. In this case, since the foam material 16 is attached to the pipe 2, the foam material 16 can be placed in the correct position in the gap 12 simply by marking the pipe 2, so that the position of the foam material 16 can be easily adjusted.

(Effect 3) The foundation penetration structure of the pipe 2 may be such that the foam material 16 is attached to the outer peripheral surface of the pipe 2 with adhesive tape 25. This allows the foam material 16 to be easily and securely attached to the outer peripheral surface of the pipe 2 simply by attaching the foam material 16 to the outer peripheral surface of the pipe 2 with adhesive tape 25. This reduces the effort required to attach the foam material 16 to the pipe 2. Then, by inserting the pipe 2 to which the foam material 16 is attached with adhesive tape 25 into the through hole portion 11 together with the foam material 16 (from the outdoor side 17 or the indoor side 15), the foam material 16 can be accurately installed in the appropriate position within the gap 12.

(Effect 4) The construction method of the foundation penetration piping is to attach a foam material 16 to the outer peripheral surface of the pipe 2, and insert and arrange the pipe 2 with the foam material 16 attached to the outer peripheral surface into the through hole portion 11 formed in the foundation 4, position the foam material 16 inside the through hole portion 11, close the gap 12 between the through hole portion 11 and the pipe 2 in the circumferential direction with the foam material 16, install the water stop material 13 in the gap 12 so as to be located on the outdoor side 17 of the foam material 16, and pour mortar 18 on the outdoor side 17 of the water stop material 13 in the gap 12. As a result, the foam material 16 can be easily installed in the gap 12 as a hold-down for the indoor side 15 of the water stop material 13, so that the foundation penetration work of the pipe 2 can be easily performed from the outdoor side 17 even after the building 1 is installed. In addition, according to the construction method of the foundation penetration piping, the same effect as the foundation penetration structure of the pipe 2 described above can be obtained.

2 Pipe 4 Foundation 11 Through hole 12 Gap 13 Water stop material 15 Indoor side 16 Foam material 17 Outdoor side 18 Mortar 25 Adhesive tape

Claims (4)

A water-swelling water-stopping material is installed in a circumferential direction in a gap between a through-hole portion formed in a foundation of a building and a pipe inserted through the through-hole portion,
A foam material is provided at a position inside the gap on the indoor side of the water-stopping material,
In the gap, at a position on the outdoor side of the water-stopping material, mortar is poured so as to be approximately flush with the outdoor surface of the foundation, forming three layers .
The foam material and the mortar sandwich and press the water-stopping material from both sides,
A foundation penetration structure for piping, characterized in that the water-swellable water-stopping material is restricted in its longitudinal expansion and is expanded in a radial direction. The foundation penetration structure for piping according to claim 1,
The foaming material is attached to the outer peripheral surface of the pipe,
The pipe is installed in the through hole portion ,
The water-swellable water-stopping material is installed from the outdoor side so that a circumferential thickness thereof is uniform after the pipe is inserted into the through-hole portion,
A foundation penetration structure for piping, characterized in that the mortar is installed from the outdoor side after the water-expanding water-stopping material is installed . The foundation penetration structure for the piping according to claim 2,
A foundation penetration structure for piping, characterized in that the foam material is attached to the outer peripheral surface of the piping with adhesive tape. Attach foam material to the outer surface of the pipe,
The piping having the foam material attached to its outer peripheral surface is inserted and disposed in a through-hole portion formed in a foundation of a building, thereby positioning the foam material inside the through-hole portion and sealing a gap between the through-hole portion and the piping in the circumferential direction with the foam material;
A water-swellable waterproofing material is placed in the gap so as to be located on the outdoor side of the foam material;
A construction method for foundation penetration piping, characterized in that mortar is poured into the gap on the outdoor side of the water-swelling material, and the water-expandable water-swelling material is sandwiched and held down on both sides between the foam material and the mortar, thereby suppressing the longitudinal expansion of the water-swelling material while allowing it to expand in the radial direction.