JP2023038042A - Waterproof thermal insulation structure of roof and construction method thereof - Google Patents

Abstract

To provide a waterproof thermal insulation structure 10 of a roof which is excellent not only in waterproofness but also in thermal insulation property and can be constructed at low cost and significantly easily, and a construction method of the same.SOLUTION: A waterproof thermal insulation structure 10 of a roof is provided between a roofing material 5 and a roof substrate material 4 of a structure and it comprises a first waterproof layer 1 formed on the roof substrate material 4 with a plurality of band-like first roofing sheets (11a, 11b) arranged in line and laid in a state where their lateral edges are overlapped each other and a second waterproof layer 2 formed on the first waterproof layer 1 with a plurality of band-like second roofing sheets (21a, 21b) arranged in line and laid in a state where their lateral edges are overlapped each other. The laying direction of the second roofing sheet and the laying direction of each of the first roofing sheet are orthogonal to each other, and thermal insulation space parts (13, 24) with a step of the lateral edge of each of the roofing sheet as a starting point are formed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a waterproof and heat-insulating roof structure and its construction method, more specifically, a waterproof and heat-insulating roof structure having excellent waterproof and heat-insulating properties provided between a roofing material and a roof base material of a building, and its construction. Regarding the method.

Conventionally, in buildings such as general houses, for example, asphalt felt, asphalt roofing, and asphalt roofing with an adhesive layer are placed between roofing materials such as tiles, slates, and sheet metal and roof base materials such as sheathing boards and sheathing boards. It is common to form a waterproof layer that prevents rain leakage on the roof by laying various roofing sheets such as. In this way, the roofing material is used for the primary waterproofing of the roof, and the roofing sheet is used for the secondary waterproofing of the roof.

However, although this roofing sheet has excellent waterproof properties, it does not have sufficient heat insulating properties. It happened to be.

Therefore, until now, there have been proposals for roof insulation structures in which a heat insulating layer made of synthetic resin foam is formed between the roofing sheet and the roof base material, or between the roofing sheet and the roofing material ( For example, Patent Document 1 below).

However, this heat insulating structure has the disadvantage that the cost is high due to the need to lay the synthetic resin foam, and the construction is troublesome.

JP-A-11-222985

The present invention has been made in view of the above-mentioned drawbacks of conventional roof insulation structures. An object of the present invention is to provide a waterproof and heat-insulating roof structure that can be constructed and a construction method thereof.

The present invention provides a waterproof and heat insulating structure for a roof provided between a roofing material and a roof base material of a building,
a first waterproof layer formed on the roof base material and formed by laying a plurality of strip-shaped first roofing sheets in parallel with their side edges overlapping each other; A second waterproof layer formed by laying a plurality of strip-shaped second roofing sheets in parallel with their side edges overlapping each other,
The laying direction of each of the second roofing sheets of the second waterproof layer is perpendicular to the laying direction of each of the first roofing sheets of the first waterproof layer,
Between the second waterproof layer and the first waterproof layer, there is a heat insulating space starting from a step formed at the side edge of each of the second roofing sheets and the side edge of each of the first roofing sheets. It is characterized by being formed

Further, according to the present invention, each of the first roofing sheets of the first waterproof layer is laid along a direction orthogonal to the slope direction of the roof, and each of the second roofing sheets of the second waterproof layer is laid along the roof It is characterized by being laid along the gradient direction of

Also, the present invention is characterized in that the first roofing sheet and the second roofing sheet are made of asphalt felt.

In the present invention, a third waterproof layer is formed on the second waterproof layer by laying a plurality of strip-shaped third roofing sheets in parallel with their side edges overlapping each other. and the laying direction of each of the third roofing sheets of the third waterproof layer and the laying direction of each of the second roofing sheets of the second waterproof layer are perpendicular to each other, and the third waterproof layer and the second waterproof layer A heat-insulating space is formed between the second roofing sheet and the layer, starting from a step formed at the side edge of each of the third roofing sheets and the side edge of each of the second roofing sheets.

Further, according to the present invention, the laying position of the overlapped portion of the third roofing sheets of the third waterproof layer coincides with the laying position of the overlapped portion of the first roofing sheets of the first waterproof layer. It is characterized by having

Further, the present invention is characterized in that the roofing material is made of sheet metal.

The present invention also provides a construction method for a waterproof and heat-insulating roof structure provided between a roofing material and a roof base material of a building, comprising:
a first waterproof layer forming step of forming a first waterproof layer by laying a plurality of strip-shaped first roofing sheets in parallel on the roof base material with their side edges overlapping each other; A plurality of strip-shaped second roofing sheets are superimposed on the first waterproof layer with their side edges overlapping each other, and the laying direction of each of the second roofing sheets and each of the first roofing sheets of the first waterproof layer A second waterproof layer forming step of forming a second waterproof layer by laying in parallel so that the laying direction of the roofing sheet is orthogonal to the laying direction,
In the second waterproof layer forming step, the side edge of each of the second roofing sheets and the side edge of each of the first roofing sheets are formed between the second waterproof layer and the first waterproof layer. It is characterized by forming an adiabatic space with the step as a starting point.

According to the roof waterproof and heat-insulating structure and construction method thereof according to the present invention, since a plurality of waterproof layers composed of a plurality of belt-shaped roofing sheets are formed, the waterproof property is excellent, and the roof is reliably prevented from leaking rain. In addition, since the heat insulating space is formed between the plurality of waterproof layers, the heat insulating property is also excellent, and it is possible to effectively prevent the occurrence of dew condensation due to the cold air outside during winter.

In addition, the heat insulating space between these waterproof layers can be formed by utilizing the step due to the thickness of the side edge of each roofing sheet without using a separate member such as a spacer, resulting in an increase in cost. It can be constructed very easily.

1 is a cross-sectional view of a main part along a slope direction X of a roof, showing a roof structure to which the waterproof and heat-insulating roof structure of the present embodiment is applied; FIG. FIG. 2 is a cross-sectional view of main parts taken along the line S1-S1 in FIG. 1; FIG. 4 is a partial perspective view for explaining a first waterproof layer forming step in the construction method for the waterproof and heat insulating structure for a roof according to the present embodiment; It is principal part sectional drawing along the slope direction X of a roof explaining the same 1st waterproof layer formation process. FIG. 5 is a cross-sectional view of main parts taken along line S2-S2 in FIG. 4; FIG. 4 is a partial perspective view for explaining a second waterproof layer forming step in the construction method for the waterproof and heat insulating structure for a roof according to the present embodiment; It is principal part sectional drawing along the direction Y orthogonal to the inclination direction X of a roof explaining the second waterproof layer formation process. FIG. 8 is a cross-sectional view of main parts taken along line S3-S3 in FIG. 7; FIG. 4 is a partial perspective view illustrating a third waterproof layer forming step in the construction method for the waterproof and heat insulating structure for a roof according to the present embodiment; It is principal part sectional drawing along the slope direction X of a roof explaining the said 3rd waterproof layer formation process. FIG. 11 is a cross-sectional view of the main part taken along line S4-S4 in FIG. 10; FIG. 11 is a partial perspective view illustrating a modified embodiment of the waterproof and heat insulating structure for a roof according to the present invention;

As shown in FIGS. 1 and 2, the roof waterproof and heat insulating structure 10 of this embodiment includes a first waterproof layer 1 formed on a roof base material 4 of a building, and a first waterproof layer 1 formed on the first waterproof layer 1. and a third waterproof layer 3 formed on the second waterproof layer 2, and provided between a roofing material 5 and a roof base material 4 of a building. .

The first waterproof layer 1 is formed by arranging a plurality of strip-shaped first roofing sheets 11 (11a, 11b) in parallel with the side edges of the first roofing sheets 11 overlapping each other on the roof base material 4. It is formed by laying. Similarly, the second waterproof layer 2 is formed by arranging a plurality of strip-shaped second roofing sheets 21 (21a, 21b) in parallel with the side edges of the second roofing sheets 21 overlapping each other to form the first waterproof layer. The third waterproof layer 3 is formed by laying on the layer 1, and the third waterproof layer 3 is formed by overlapping a plurality of strip-shaped third roofing sheets 31 (31a, 31b) with the side edges of each third roofing sheet 31 overlapping each other. It is formed by laying on the second waterproof layer 2 in parallel in a combined state.

Between the roof base material 4 and the first waterproof layer 1 of the building, a heat insulating space 13 is formed, and between the first waterproof layer 1 and the second waterproof layer 2, a heat insulating space ( 23 and 24) are formed, heat insulation spaces (33 and 34) are formed between the second waterproof layer 2 and the third waterproof layer 3, and between the third waterproof layer 3 and the roofing material 5 A heat insulating space 35 is formed in the .

The roof waterproof and heat insulating structure 10 of the present embodiment waterproofs the roof with the plurality of first waterproof layers 1, the second waterproof layers 2, and the third waterproof layers 3, and the plurality of heat insulating spaces (13, 23 , 24, 33, 34, 35) to insulate the roof.

Each component of the waterproof and heat-insulating roof structure 10 will be described in detail below while sequentially describing the construction steps (FIGS. 3 to 11) of the waterproof and heat-insulating roof structure 10 of the present embodiment.

First, as shown in FIGS. 3 to 5, a first waterproof layer forming step is performed to form the first waterproof layer 1 on the roof base material 4 of the building. That is, as shown in FIG. 3, a long strip-shaped first roofing sheet 11 is laid while being unwound from a roll R along a direction Y orthogonal to the roof slope direction X, thereby forming a plurality of first roofing sheets. The first waterproof layer 1 is formed over the entire upper surface of the roof base material 4 by arranging the first waterproof layer 11 in parallel in the roof slope direction X with the side edges thereof overlapping each other.

In this embodiment, the first roofing sheet 11 is made of felt base paper impregnated with asphalt and has a width of 100 cm and a thickness of about 1 mm. As shown in FIG. 4, the roof base material 4 consists of a sheathing board 41 made of structural plywood and a sheathing board 42 made of a wood fiber board coated with a water-resistant agent and having excellent waterproof, moisture-permeable, and sound-absorbing properties. The side edges of the first roofing sheet 11 are stapled to the sheathing boards 41 of the roof base material 4 . Of course, the roof base material 4 may be composed only of sheathing boards 41 made of structural plywood.

The plurality of first roofing sheets 11 are laid in order from the eaves 43 side of the roof toward the top of the roof slope and are arranged side by side, and as shown in FIG. The lower side edge of the first roofing sheet 11b on the slope upper side overlaps with the side edge of . In this way, overlapping portions 12 in which adjacent first roofing sheets 11 are overlapped are formed in a plurality of rows parallel to the Y direction.

By this first waterproof layer forming step, a step formed by the upper side edge portion 111 of the first roofing sheet 11a on the lower slope side is formed between the first waterproof layer 1 and the roof base material 4. A space 13 is formed. Various roofing sheets such as asphalt felt have a predetermined thickness necessary to ensure waterproofness. Moreover, although it has the flexibility necessary to ensure its workability, it has a predetermined bending stiffness. Therefore, the heat-insulating space 13 formed by utilizing the step due to the thickness of the side edge portion 111 of the first roofing sheet 11a on the lower side of the gradient will not be formed on the upper side of the gradient unless it is actively collapsed during construction. It is formed so as to extend to the central portion of the first roofing sheet 11b.

Moreover, in the present embodiment, asphalt felt without an adhesive layer is used as the first roofing sheet 11, and only the side edges thereof are stapled. A gap (not shown) exists between the upper surface of the roof base material 4 and the portion does not adhere to the roof base material 4 . In this embodiment, a wide-ranging heat-insulating space 13 that is continuous with this gap is formed.

Next, as shown in FIGS. 6 to 8, a second waterproof layer forming step of forming the second waterproof layer 2 on the first waterproof layer 1 is performed. That is, as shown in FIG. 6, a long belt-shaped second roofing sheet 21 is laid while being unwound from a roll R along the slope direction X of the roof. The second waterproof layer 2 is formed over the entire upper surface of the first waterproof layer 1 by arranging them in parallel in the direction Y while overlapping each other. The laying direction of each second roofing sheet 21 of the second waterproof layer 2 is perpendicular to the laying direction of each first roofing sheet 11 of the first waterproof layer 1 .

In this embodiment, similarly to the first roofing sheet 11, asphalt felt having a width of 100 cm and a thickness of about 1 mm, which is obtained by impregnating felt base paper with asphalt, is used as the second roofing sheet 21. are overlapped by about 10 cm. Only the side edges of each second roofing sheet 21 are stapled to the sheathing board 41 of the roof base material 4 .

The plurality of second roofing sheets 21 are laid in order from one verge side of the roof to the other verge 44 side and are arranged side by side, and as shown in FIG. At this time, the left side edge of the right second roofing sheet 21b overlaps the right side edge of the left second roofing sheet 21a. In this way, overlapping portions 22 in which adjacent second roofing sheets 21 are overlapped are formed in a plurality of rows parallel to the slope direction X of the roof. As for how to stack the second roofing sheets 21, when viewed upward from the slope of the roof, the right side of the second roofing sheet is placed on the left side edge of the right side of the second roofing sheet. The side edges may overlap. It can be appropriately selected in consideration of the north, south, east, and west directions of the roof.

By this second waterproof layer forming step, as shown in FIG. 7, between the second waterproof layer 2 and the first waterproof layer 1, a thickness At the same time, as shown in FIG. 8, a step generated by the thickness of the lower side edge portion 111 of the first roofing sheet 11b on the upper slope side is formed as a starting point. A heat insulating space 24 is formed. The heat insulating space 23 and the heat insulating space 24 communicate with each other in the vicinity of the intersection of the overlapped portion 22 of the second waterproof layer 2 and the overlapped portion 12 of the first waterproof layer 1 . As a result, between the second waterproof layer 2 and the first waterproof layer 1, heat-insulating spaces (23, 24) extending in a grid pattern over the entire roof surface of the building are formed. Note that these heat insulating space portions (23, 24) also spread from the step at the side edge of each roofing sheet to the central portion of the other adjacent roofing sheet, similarly to the heat insulating space portion 13 described above. Widespread formation.

Next, as shown in FIGS. 9 to 11, a third waterproof layer forming step of forming a third waterproof layer 3 on the second waterproof layer 2 is performed. That is, as shown in FIG. 9, a long strip-shaped third roofing sheet 31 is laid while being unwound from a roll R along a direction Y perpendicular to the roof slope direction X, and a plurality of third roofing sheets 31 are laid. are arranged in parallel in the direction X of the slope of the roof with their side edges overlapping each other to form the third waterproof layer 3 over the entire upper surface of the second waterproof layer 2 . The laying direction of each third roofing sheet 31 of the third waterproof layer 3 is perpendicular to the laying direction of each second roofing sheet 21 of the second waterproof layer 2, and the laying direction of each first roofing sheet 11 of the first waterproof layer 1. parallel to the direction

In this embodiment, similar to the first roofing sheet 11, as the third roofing sheet 31, asphalt felt having a width of 100 cm and a thickness of about 1 mm, which is obtained by impregnating felt base paper with asphalt, is used. are overlapped by about 10 cm. Only the side edges of each third roofing sheet 31 are stapled to the sheathing board 41 of the roof base material 4 .

The plurality of third roofing sheets 31 are laid in order from the eaves 43 side of the roof toward the top of the roof slope and are arranged side by side. The lower side edge of the third roofing sheet 31b on the slope upper side overlaps with the side edge of . In this way, a plurality of rows of overlapping portions 32 in which the adjacent third roofing sheets 31 are overlapped are formed in parallel with the Y direction. In this embodiment, the laying position of the overlapped portion 32 of the third waterproof layer 3 and the laying position of the overlapped portion 12 of the first waterproof layer 1 are matched.

By this third waterproof layer forming step, as shown in FIG. At the same time as the heat insulation space 33 is formed starting from the step caused by the thickness, the left side edge of the right second roofing sheet 21b is formed as shown in FIG. A heat insulating space portion 34 is formed starting from a step caused by the thickness of the portion 211 . The heat insulating space 33 and the heat insulating space 34 communicate with each other in the vicinity of the intersection between the overlapped portion 32 of the third waterproof layer 3 and the overlapped portion 22 of the second waterproof layer 2 . As a result, between the third waterproof layer 3 and the second waterproof layer 2, heat insulating spaces (33, 34) extending in a grid pattern over the entire roof surface of the building are formed. As with the heat insulating space portion 13, these heat insulating space portions (33 and 34) spread from the stepped edge of each roofing sheet to the central portion of the other adjacent roofing sheet. Widespread formation.

The waterproof and heat-insulating roof structure 10 of the present embodiment is constructed on the roof base material 4 by sequentially performing the first waterproof layer forming step to the third waterproof layer forming step.

After that, as shown in FIGS. 1 and 2, various roofing materials 5 such as roof tiles, slates, sheet metal, etc. are laid on the third waterproof layer 3 of the roof waterproof and heat insulating structure 10 of this embodiment. Building roofs are constructed. In this embodiment, strip-shaped sheet metal made of aluminum-zinc alloy plated steel sheet is used as the roofing material 5, and a plurality of sheet metals are vertically flat-roofed along the slope direction X of the roof.

In addition, the waterproof and heat insulating structure 10 of the roof of this embodiment has a triple intersection of the overlapped portion 12 of the first waterproof layer 1, the overlapped portion 22 of the second waterproof layer 2, and the overlapped portion 32 of the third waterproof layer 3. The total thickness of the waterproof layer is the largest at the part, and recesses are formed on the upper surface of the third waterproof layer 3 except for the triple crossing part. Therefore, when the roofing material 5 is laid on the third waterproof layer 3, as shown in FIGS. A heat-insulating space 35 communicating with each other is formed at the end.

As described above, according to the roof waterproof and heat insulating structure 10 of the present embodiment, a plurality of the first waterproof layer 1, the second waterproof layer 2, and the third waterproof layer 3 each composed of a plurality of strip-shaped roofing sheets are formed. Therefore, its waterproofness is extremely excellent, and it is possible to reliably prevent roof leaks, etc., and between the roof base material 4 and the first waterproof layer 1, the first waterproof layer 1 and the second waterproof layer 2 Between, between the second waterproof layer 2 and the third waterproof layer 3, and between the third waterproof layer 3 and the roofing material 5, a plurality of heat insulating spaces (13, 23, 24, 33, 34, 35) is formed, the heat insulation is also excellent, and it is possible to effectively prevent the occurrence of dew condensation due to the outside cold air in winter.

Moreover, according to the roof waterproof and heat insulating structure 10 of the present embodiment, the heat insulating space portions (23, 24, 33, 34) between the first waterproof layer 1, the second waterproof layer 2, and the third waterproof layer 3 are , For example, without using a separate member such as a spacer, it can be formed by utilizing the step due to the thickness of the side edge of each roofing sheet. Easy to construct.

Although the waterproof and heat-insulating roof structure 10 of the present embodiment has been described above, the present invention can also be implemented in other embodiments.

For example, in the above embodiment, the laying position of the overlapping portion 32 of the third waterproof layer 3 is aligned with the laying position of the overlapping portion 12 of the first waterproof layer 1, but the present invention is not necessarily limited to this. Alternatively, as shown in FIG. 12, the laying position of the overlapping portion 32 of the third waterproof layer 3 may be different from the laying position of the overlapping portion 12 of the first waterproof layer 1 . As a result, the formation positions of the heat insulating space 33 formed along the overlapping portion 32 of the third waterproof layer 3 and the heat insulating space 13 formed along the overlapping portion 12 of the first waterproof layer 1 can be shifted, and each heat insulating space (33, 13) can be formed more uniformly over the entire roof surface.

Further, in the above embodiment, the first roofing sheet 11 of the first waterproof layer 1 is laid along the direction Y orthogonal to the roof slope direction X, and the second roofing sheet 21 of the second waterproof layer 2 is laid along the roof. The third roofing sheet 31 of the third waterproof layer 3 is laid along the direction Y of the roof, but the present invention is not necessarily limited to this. The first roofing sheet 11 of layer 1 is laid along the roof slope direction X, the second roofing sheet 21 of the second waterproof layer 2 is laid along the roof direction Y, and the third roofing sheet 21 of the third waterproof layer 3 is laid. The roofing sheet 31 may be laid along the slope direction X of the roof. The laying direction of each roofing sheet can be appropriately changed in design, for example, considering the type of roofing material 5 and its laying direction.

In the above embodiment, the same asphalt felt is used for the first roofing sheet 11, the second roofing sheet 21 and the third roofing sheet 31, but the present invention is of course not limited to this. For example, various roofing sheets such as asphalt roofing and asphalt roofing with an adhesive layer can be used as appropriate. Moreover, in each waterproof layer of the first waterproof layer 1, the second waterproof layer 2, and the third waterproof layer 3, the kind, width, thickness, etc. of the strip-shaped roofing sheet may be varied.

Moreover, the waterproof and heat insulating structure of the roof according to the present invention may be composed of a two-layer structure consisting only of the first waterproof layer 1 and the second waterproof layer 2, or may be composed of four or more waterproof layers. good.

The present invention can also be implemented in various forms with various improvements, modifications, and variations based on the knowledge of those skilled in the art without departing from the spirit of the present invention. In addition, any of the matters specifying the invention may be replaced with other techniques within the scope of producing the same action or effect, and the integrally configured matters specifying the invention may be constructed from a plurality of members. Alternatively, the matters specifying the invention, which are composed of a plurality of members, may be implemented in a form integrally configured.

10 Roof waterproof and heat insulating structure 1 First waterproof layer 11 First roofing sheet 111 (of first roofing sheet) side edge 12 Overlapping portion (of first roofing sheets) 13 Heat insulating space 2 Second waterproof layer 21 Second roofing sheet 211 (of second roofing sheet) side edge 22 Overlapping portions 23 and 24 (of second roofing sheets) Heat insulating space
3 Third waterproof layer 31 Third roofing sheet 311 (of the third roofing sheet) Side edge portion 32 Overlapping portions (of third roofing sheets) 33, 34, 35 Heat insulation space portion 4 Roof base material 5 Roofing material X Roof slope direction Y Direction perpendicular to the roof slope direction

Claims (7)

A waterproof and heat-insulating roof structure provided between a roofing material and a roof base material of a building,
a first waterproof layer formed on the roof base material and formed by laying a plurality of strip-shaped first roofing sheets in parallel with their side edges overlapping each other;
a second waterproof layer formed on the first waterproof layer and formed by laying a plurality of strip-shaped second roofing sheets in parallel with their side edges overlapping each other;
with
The laying direction of each of the second roofing sheets of the second waterproof layer is perpendicular to the laying direction of each of the first roofing sheets of the first waterproof layer,
Between the second waterproof layer and the first waterproof layer, there is a heat insulating space starting from a step formed at the side edge of each of the second roofing sheets and the side edge of each of the first roofing sheets. A waterproof and heat-insulating structure for a roof, characterized by: each of the first roofing sheets of the first waterproof layer is laid along a direction perpendicular to the slope direction of the roof;
2. The roof waterproof and heat-insulating structure according to claim 1, wherein each of said second roofing sheets of said second waterproof layer is laid along the slope direction of the roof. 3. The waterproof and heat-insulating roof structure according to claim 1, wherein the first roofing sheet and the second roofing sheet are made of asphalt felt. A third waterproof layer is formed on the second waterproof layer by laying a plurality of strip-shaped third roofing sheets in parallel with their side edges overlapping each other,
The laying direction of each of the third roofing sheets of the third waterproof layer and the laying direction of each of the second roofing sheets of the second waterproof layer are perpendicular to each other,
Between the third waterproof layer and the second waterproof layer, there is a heat insulating space starting from a step formed at the side edge of each of the third roofing sheets and the side edge of each of the second roofing sheets. The waterproof and heat insulating structure for a roof according to any one of claims 1 to 3, characterized in that it is formed. The laying position of the overlapped portion of the third roofing sheets of the third waterproof layer coincides with the laying position of the overlapped portion of the first roofing sheets of the first waterproof layer. The waterproof and heat insulating structure for a roof according to claim 4. 6. The waterproof and heat insulating structure for a roof according to any one of claims 1 to 5, wherein the roofing material is made of sheet metal. A construction method for a waterproof and heat-insulating roof structure provided between a roofing material and a roof base material of a building, comprising:
a first waterproof layer forming step of forming a first waterproof layer by laying a plurality of strip-shaped first roofing sheets in parallel on the roof base material with their side edges overlapping each other;
A plurality of strip-shaped second roofing sheets are superimposed on the first waterproof layer with their side edges overlapping each other, and the laying direction of each second roofing sheet and each of the first waterproof layers A second waterproof layer forming step of forming a second waterproof layer by laying in parallel so that the laying direction of one roofing sheet is perpendicular to the laying direction;
with
In the second waterproof layer forming step, the side edge of each of the second roofing sheets and the side edge of each of the first roofing sheets are formed between the second waterproof layer and the first waterproof layer. A method for constructing a waterproof and heat-insulating structure for a roof characterized by forming a heat-insulating space starting from a step.

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