Construction method and structure of flashing at interface between concrete wall and steel roof

Abstract

The application discloses a construction method and structure for a flashing joint between a concrete wall and a steel roof. The construction method comprises the following steps: a groove is formed at the joint between the concrete wall and the steel roof, and the groove is cleaned; a flashing plate is provided, the flashing plate is bent at the head to form a first side plate and a second side plate, a flexible adhesive layer is applied at the lower part of the groove, the first side plate is attached to the bottom wall and is locked by a fastener, and the second side plate is arranged above the flexible adhesive layer to form a weak adhesive interface; a hard foam strip is attached to the upper side of the second side plate; a rigid adhesive layer is applied between the hard foam strip and the upper concrete body to form a strong adhesive interface. Through mechanical anchoring of the L-shaped structure and asymmetric adhesive design of the upper and lower parts, a weak release area is artificially constructed, and the deformation stress is accurately guided to the preset weak adhesive interface for release, the upper concrete joint surface is protected from damage, and the problem that structural leakage is caused by the fact that stress cannot be released in traditional full-rubber construction is solved.

Description

Technical Field

[0001] This application relates to the field of building waterproofing construction technology, and in particular to a construction method and structure for flashing at the interface of concrete wall and steel roof. Background Technology

[0002] Currently, waterproofing at the junction of concrete walls and steel roofs is a common construction challenge in building engineering. The existing conventional method involves adding a drip edge ("eagle beak") to the concrete wall and applying waterproof sealant to both the bottom and top of the flashing. However, this traditional approach has significant drawbacks in practice: First, during concrete construction, due to the difficulty in setting up formwork, the "eagle beak" structure is often omitted or poorly formed, leading to the failure of the dripping mechanism.

[0003] Secondly, after the flashing is fully bonded, the adhesive will shrink during the drying process, and the concrete wall and steel roof will deform inconsistently under wind loads and temperature changes (thermal expansion and contraction). Due to the different bonding forces between the structural adhesive and the concrete and the two sides of the steel roof, the deformation stress cannot be effectively released, making it very easy for cracks to occur at the weakest point, the "adhesive-concrete interface".

[0004] Once the bond between the cement and concrete surfaces cracks, rainwater will seep directly into the walls and underlying structure from the moment the installation is completed, causing serious leakage. This type of structural cracking caused by stress is difficult to solve with simple surface repairs, resulting in frequent maintenance after the house is handed over. This is not only costly in terms of manpower and resources, but also cannot guarantee that the building will not leak in the long term, seriously affecting the building's lifespan and the living experience. Summary of the Invention

[0005] This application provides a construction method and structure for flashing at the interface between a concrete wall and a steel roof, aiming to solve the problem of cracking and leakage at the interface between the concrete wall and the steel roof caused by the inability to release deformation stress in the prior art.

[0006] To achieve the above objectives, this application proposes a construction method for flashing at the interface between a concrete wall and a steel roof, which includes the following steps: S1, create and clean the groove at the interface between the concrete wall and the steel roof; S2, a flashing plate is provided, the head of which is bent to form a first side plate and a second side plate; a flexible adhesive layer is applied to the lower part of the tank; the first side plate is attached to the bottom wall of the tank and locked with fasteners, and the second side plate is pressed on the flexible adhesive layer to form a flexible adhesive interface that allows relative sliding; S3, rigid foam strips are bonded to the upper side of the second side panel using double-sided adhesive. S4. A rigid bonding layer is applied between the rigid foam board strip and the upper concrete body to form a rigid bonding interface that restricts relative displacement.

[0007] In some embodiments, the flexible adhesive layer is made of a low-modulus sealing material, and the rigid adhesive layer is made of a high-modulus weather-resistant sealing material.

[0008] In some embodiments, in step S2, before applying the flexible adhesive layer, a release medium is applied or a release film is laid in a local area of ​​the bottom surface of the second side plate to form a local non-full adhesive structure between the bottom surface of the second side plate and the flexible adhesive layer.

[0009] In some embodiments, the fasteners are staggered along the length of the first side plate, and the heads of the fasteners are recessed into the surface of the first side plate.

[0010] This application also provides a flashing structure based on the interface between a concrete wall and a steel roof, the flashing structure comprising: A groove set in a concrete wall; The flashing plate has its head bent to form a first side plate and a second side plate, with the first side plate attached to the bottom wall of the trough. Fasteners are used to secure the first side plate to the bottom wall of the groove. A flexible adhesive layer is filled between the lower side of the second side plate and the lower part of the groove to form a weak adhesive interface; Rigid foam strips are provided on the upper side of the second side plate; A rigid bonding layer is fully filled between the rigid foam strips and the upper concrete body to form a strong bonding interface.

[0011] In some embodiments, the rigid adhesive layer covers the upper end face and outer side face of the rigid foam board strip and seals the connection between the upper concrete body and the second side plate.

[0012] In some embodiments, a flexible reinforcing mesh layer is composited between the rigid foam strip and the rigid adhesive layer.

[0013] In some embodiments, the upper edge of the tank is inclined outwards to form an outward-sloping water-facing surface.

[0014] In some embodiments, the outdoor end of the flashing is bent downward to form a windproof and suction-proof folded edge, which extends into the interior of the steel gutter; the outer surface of the flashing is provided with a guide slope that is inclined toward the steel gutter.

[0015] In some embodiments, the flashing has a hydrophobic coating on its water-facing surface and outer surface.

[0016] This application proposes a construction method and structure for flashing at the interface between a concrete wall and a steel roof. The construction method includes the following steps: S1, creating and cleaning a trench at the interface between the concrete wall and the steel roof; S2, providing a flashing board with its head bent to form a first side plate and a second side plate; applying a flexible adhesive layer to the lower part of the trench; attaching the first side plate to the bottom wall of the trench and securing it with fasteners; pressing the second side plate onto the flexible adhesive layer to form a flexible adhesive interface that allows relative slippage; S3, bonding rigid foam strips to the upper side of the second side plate with double-sided adhesive; S4, applying a rigid adhesive layer between the rigid foam strips and the upper concrete body to form a rigid adhesive interface that restricts relative displacement. This application's technical solution has the following beneficial effects: (1) By designing the flashing head as L-shaped and using an asymmetrical bonding structure of “strong at the top and weak at the bottom”, the uncontrollable deformation stress is precisely guided to the preset weak bonding interface for release, eliminating the tearing and damage of the upper concrete bonding surface and achieving long-term reliable waterproofing.

[0017] (2) The process of applying flexible glue first and then pressing the plate and nailing is adopted, combined with L-shaped lateral anchoring, which greatly improves the mechanical pull-out strength, and the fasteners are hidden in the groove, avoiding the risk of corrosion.

[0018] (3) Actively design local non-full-bonding structures (such as isolation membranes or low-bonding pads) and artificially intervene in the stress release path to keep cracks within a controllable range, which greatly improves the durability of the joint. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a schematic diagram of the structure of a pump source according to an embodiment of this application; Figure 2 This is a structural schematic diagram of the flashing structure at the interface between a concrete wall and a steel roof, according to an embodiment of this application. Figure 3 for Figure 2 An enlarged schematic diagram of the middle structure S. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] It should be noted that, unless otherwise stated or limited, all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0022] It should also be noted that, unless otherwise stated or limited, when an element is referred to as "fixed to" or "set on" another element, it may be directly on the other element or there may be an intervening element present. When an element is referred to as "connected to" another element, it may be directly connected to the other element or there may be an intervening element present.

[0023] Furthermore, unless otherwise stated or limited, the descriptions involving "first," "second," etc., in this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0024] Before detailing the specific implementation methods of this application, the core mechanical design concept of this application will first be explained. In building engineering, concrete walls and steel roofs 200 are two material systems with drastically different physical properties. The steel roof 200 is a lightweight structure with extremely high thermal sensitivity, which will undergo significant linear expansion, contraction, and high-frequency micro-vibration under drastic changes in ambient temperature and wind loads; while the concrete wall 100 is a heavy structure with high thermal inertia, and its deformation is relatively slow and minimal. These two structures will generate strong and continuous relative displacement and alternating stress at the interface.

[0025] The core inventive concept of this application lies in introducing a theoretical model of "asymmetric bond stress release" and combining it with a specific spatial structure design. Specifically, by artificially and actively constructing a bond interface with "strong upper constraint and weak lower release," uncontrollable and destructive alternating stress is precisely guided to the preset and controllable weak bond interface to cause slippage or peeling. This completely dissipates the deformation stress within the preset area, thoroughly protecting the upper strong bond interface and the cement-concrete bond surface from damage, achieving a long-term reliable waterproof seal.

[0026] Specifically, this application provides a construction method for flashing at the interface of a concrete wall and a steel roof. This construction method, through a specific construction sequence and material arrangement, creates a waterproof joint structure between the concrete wall 100 and the steel roof 200, allowing for active stress release. Referring to the figures, the construction method for flashing at the interface of the concrete wall and the steel roof specifically includes the following steps: Step S1: Create and clean the groove at the interface between the concrete wall 100 and the steel roof 200.

[0027] Specifically, on the side of the vertical concrete wall 100, near the top of the gutter of the steel roof 200, a groove (i.e., a slot) of a certain depth and width is cut using a cutting machine or a grooving machine. The purpose of cutting the slot is twofold: first, to provide physical space for the subsequent embedding of the L-shaped flashing 10, allowing the fixing end of the flashing 10 to be concealed inside the wall, preventing the fasteners 40 from being directly exposed to the outdoor environment and causing corrosion; second, to change the distribution of the stress-bearing cross-section, providing a spatial basis for constructing an asymmetrical bonding layer; and finally, grooving can remove the laitance and weak layers generated on the surface of the concrete wall 100 during construction, exposing the more robust concrete substrate inside, which is beneficial for improving the anchoring force of the subsequent adhesive. Regarding the selection of grooving equipment, in addition to conventional diamond cutting machines, water-cooled grooving machines can also be used to reduce dust and cool the blades. For concrete walls 100 with higher hardness, even hydraulic grooving machines can be used to ensure the flatness of the slot edges.

[0028] After the groove is cut, cleaning is required. During the grooving process, the concrete wall 100 generates a large amount of dust, debris, and micro-cracks. If these are not removed, they will severely affect the chemical adhesion between the subsequent flexible bonding layer 20 and rigid bonding layer 50 and the concrete. The cleaning steps include using high-pressure air to blow away surface laitance and using a wire brush to grind away surface laitance. More preferably, after cleaning, a primer can be applied for interface treatment. The primer can penetrate and cure the dust on the concrete surface, sealing micropores, thereby greatly improving the wetting and adhesion of the subsequent adhesive to the concrete substrate. The specific type of primer can be matched according to the type of sealant used subsequently. For example, a silane coupling agent primer can be used for silicone sealant, and an isocyanate primer can be used for polyurethane sealant.

[0029] Furthermore, the shape of the drainage channel does not necessarily have to be a standard rectangle. To enhance subsequent drainage and increase the upper bonding area, the upper edge of the channel can be inclined outwards, forming an outward-sloping water-facing surface. This outward-sloping design utilizes gravity, ensuring that even if a small amount of water comes into contact with this area, it will slide outwards along the direction of gravity, preventing water from accumulating on the upper edge of the channel and causing capillary backflow, thus constructing the first line of defense in terms of physical form. The inclination angle is usually controlled between 5 and 15 degrees, ensuring good drainage without excessively increasing the difficulty of channel construction.

[0030] Step S2: Provide a flashing plate with its head bent to form a first side plate and a second side plate; apply a flexible adhesive layer to the lower part of the tank; attach the first side plate to the bottom wall of the tank and lock it with fasteners, and press the second side plate on top of the flexible adhesive layer to form a flexible adhesive interface that allows relative sliding.

[0031] This step is the core of the entire construction method, involving the shape design, positioning and anchoring of the flashing 10, and the construction of the lower weak bonding interface.

[0032] First, the flashing 10 is typically formed by bending metal sheets such as galvanized steel or aluminum alloy. Its head (the end closest to the concrete wall 100) is bent into an "L" shape, forming a first side plate 101 and a second side plate 102. Here, the first side plate 101 corresponds to the vertical extension of the L-shape, and the second side plate 102 corresponds to the horizontal extension of the L-shape. This integrated bending process ensures the overall rigidity of the head, avoiding stress concentration and weak points in corrosion resistance caused by welding. The material selection for the flashing 10 is not limited to galvanized steel; it can also be aluminum alloy, stainless steel, or high-strength fluorocarbon coated color steel, or even polymer composite panels. As long as it possesses sufficient mechanical strength and weather resistance, and its head can be bent into an L-shape through cold or hot bending processes, it can be used as the base material for the flashing 10 of this application. For highly corrosive coastal areas, 316 stainless steel or thick-coated aluminum alloy is preferred. The bending radius should be greater than twice the material thickness to avoid micro-cracks at the bending point.

[0033] In terms of construction sequence, a flexible adhesive layer 20 is first applied to the lower part of the tank, and then the flashing 10 is pressed and fixed. Understandably, if the flashing 10 is fixed first and then adhesive is applied from the side or gaps, the adhesive is difficult to evenly fill the gaps at the bottom, easily creating air bubbles and voids, leading to localized adhesion failure. However, by first evenly applying the flexible adhesive layer 20 (like a base coat) to the lower part of the tank, and then directly pressing the second side plate 102 onto this adhesive layer, the adhesive will naturally spread outwards under gravity and pressure, ensuring full-area contact and density of the bottom surface, eliminating the risk of interface air bubbles. When applying the flexible adhesive layer 20, a trowel or a special adhesive nozzle should be used to evenly apply the adhesive to the lower part of the tank, with a thickness slightly higher than the final design thickness, ideally allowing the adhesive to be moderately squeezed out from the edges after the flashing 10 is pressed in.

[0034] When applying the flexible adhesive layer 20, a low-modulus sealant is used. Low modulus means the material is very soft, with extremely high elongation at break and low tensile and shear strength. Its function is not to hold the flashing 10 firmly, but to provide a flexible buffer, allowing the flashing 10 to slide relative to its surface without damaging the structure of the adhesive itself. The flexible adhesive layer 20 emphasizes "low modulus and high elongation," and can be made of low-modulus polysulfide sealant or modified silicone polyether sealant, or a specially formulated low-hardness silicone sealant. In extremely cold regions, a modified silicone polyether sealant with excellent low-temperature resistance should be selected to ensure that it remains flexible and does not become brittle at extremely low temperatures.

[0035] Subsequently, the first side plate 101 is attached to the bottom wall of the trench (i.e., the deepest part of the trench), and fasteners 40 (such as nails, self-tapping screws, etc.) are used to lock the first side plate 101 deep into the concrete wall 100. This L-shaped anchoring method has significant mechanical advantages: the first side plate 101 is attached to the vertical bottom wall, and the fasteners 40 are driven horizontally or laterally into the wall. The force direction of the fasteners 40 forms a certain angle with the direction of the external pull-out force, which multiplies the holding force of the wall on the fasteners 40 and greatly improves the pull-out resistance. At the same time, the fasteners 40 are hidden inside the trench and covered by the subsequent colloid and foam board, which completely isolates moisture and eliminates the risk of corrosion and breakage of the fasteners 40. In addition to nails and self-tapping screws, fasteners 40 can also be used for concrete walls 100 with lower strength or hollow areas. These fasteners can be metal anchors or chemical anchors with expansion sleeves to ensure that the anchoring force of the first side plate 101 on the bottom wall meets the wind-shearing design requirements. The material of fasteners 40 should match the material of flashing 10 or have a small potential difference to prevent electrochemical corrosion. For example, aluminum alloy flashing 10 should be fitted with stainless steel screws.

[0036] To further optimize the anchoring effect, the fasteners 40 are staggered along the length of the first side plate 101, with the heads of the fasteners 40 recessed into the surface of the first side plate 101. The staggered arrangement prevents stress concentration along a straight line, which could lead to concrete cracking. The recessed heads ensure a smooth fit with the second side plate 102 (or subsequent filler material), preventing interference gaps caused by protruding nail heads and avoiding stress concentration points within the adhesive. The recess depth should be controlled so that the head of the fastener 40 is flush with or slightly below the surface of the first side plate 101 by no more than 0.5 mm; excessive depth will weaken the effective thickness of the first side plate 101.

[0037] When the second side plate 102 is pressed onto the flexible adhesive layer 20, a flexible adhesive interface that allows relative slippage is formed. Here, "allowing relative slippage" is a relative concept, relative to the rigid interface that restricts relative displacement in subsequent steps.

[0038] To further precisely control the slip threshold of this interface that allows relative slippage and ensure that stress is released at this point, this embodiment also provides a preferred implementation: before applying the flexible adhesive layer 20, a release medium or a release film is applied to a predetermined area on the bottom surface of the second side panel 102. The release medium (such as silicone oil, a specific release agent) or the release film (such as polyethylene film, single-sided tape) serves to physically block the chemical bonding between the adhesive and the metal plate. By arranging the release medium in the predetermined area (usually the central area of ​​the bottom surface of the second side panel 102), this area becomes completely non-adhesive; while the edges without the release medium remain bonded to the adhesive. This forms a "partially non-fully bonded structure." When the flashing 10 is stretched, due to the detachment in the middle and the limited adhesive force at the edges, the entire bottom surface of the second side panel 102 is prone to slippage and peeling. This proactive control of the bonding area allows the design intent of "artificially guiding cracks" to be realized, unaffected by batch differences in the adhesive or fluctuations in the adhesive modulus caused by changes in ambient temperature. In addition to laying a physical isolation membrane, a low surface energy coating (such as a Teflon coating) of a specific shape can be applied to the bottom surface of the second side plate 102 by screen printing or spraying. As long as it can achieve the purpose of weakening the adhesion of the central area, it should be regarded as an equivalent replacement.

[0039] Step S3: Adhere rigid foam strips to the upper side of the second side panel using double-sided adhesive.

[0040] After completing the construction and mechanical anchoring of the lower weak bonding interface, the construction of the upper strong constraint zone begins. First, rigid foam strips are attached to the upper side of the second side plate 102 (i.e., the side facing the trench opening and the concrete above) using double-sided adhesive.

[0041] The rigid foam strips do not directly waterproof the surface, but rather serve as a supporting framework and backing material for the rigid bonding layer 50. In this embodiment, rigid closed-cell foam boards (such as high-density extruded polystyrene boards) are used. The closed-cell structure makes them completely non-absorbent, and their high density and rigidity allow them to withstand the pressure of the top layer of structural adhesive without collapsing or deforming, ensuring the dimensional stability of the cross-section of the upper strong bonding area. Besides high-density extruded polystyrene boards, high-density rigid polyurethane foam boards or phenolic foam boards can also be used. The key is that they must possess sufficient compressive strength to resist the injection pressure and long-term gravity, and the closed-cell ratio must reach an extremely high level to ensure non-absorption. Their density should generally not be less than 30 kg / m³ to provide sufficient supporting rigidity.

[0042] The initial bonding with double-sided tape is primarily for temporary positioning of the rigid foam strips during construction. Because rigid foam strips are lightweight, if not secured, they are easily displaced by the subsequent application of high-viscosity structural adhesive, leading to uneven filling or voids. The double-sided tape provides sufficient initial bonding force, ensuring the foam strips remain stably positioned on the upper side of the second side panel 102 before the subsequent adhesive curing. Solvent-free pressure-sensitive double-sided tape should be used to avoid solvent evaporation adversely affecting the curing of the subsequent structural adhesive.

[0043] Step S4: Apply a rigid bonding layer between the rigid foam board strip and the upper concrete body to form a rigid bonding interface that restricts relative displacement.

[0044] Finally, a rigid bonding layer 50 is applied fully above and around the rigid foam strips, within the remaining cavity between the rigid foam strips and the upper concrete of the trench. The rigid bonding layer 50 uses a high-modulus, weather-resistant sealing material (such as high-strength silicone structural adhesive or polyurethane structural adhesive). High modulus means that the material, after curing, has high hardness, high tensile strength, minimal deformation, and almost no ductility. The key to the rigid bonding layer 50 is "high modulus and high bonding strength." High-strength epoxy resin structural adhesive, polyurethane structural adhesive, or even epoxy resin potting compound combined with fiberglass mesh can be used to achieve ultimate rigid support. During the application process, the adhesive should be applied at a uniform speed from one end to the other, supplemented by vibration or leveling tools to ensure that there are no air bubbles inside the adhesive and that it is fully wetted and in contact with the rigid foam strips and the concrete.

[0045] After the rigid bonding layer 50 is fully applied, it completely covers the upper end and outer side of the rigid foam board strip, forming a tight seal with the upper concrete and the second side plate 102. Because the rigid foam board strip provides solid internal support, the structural adhesive will not sag or collapse due to its own weight or a hollow lower section, ensuring the fullness and density of the adhesive cross-section.

[0046] This creates a rigid bonding interface that restricts relative displacement. The bonding strength and stiffness of this interface are much greater than those of the lower, more flexible bonding interface. The upper structural adhesive firmly binds the second side plate 102, the rigid foam strips, and the upper concrete together, forming an immovable rigid defense line.

[0047] This application also provides a flashing structure for the interface between a 100mm concrete wall and a 200mm steel roof, implemented based on the construction method of Embodiment 1, see reference. Figure 2 As shown, the flashing structure includes a channel in the concrete wall 100, a flashing plate 10, fasteners 40, a flexible adhesive layer 20, rigid foam strips, and a rigid adhesive layer 50.

[0048] The head of the flashing slab 10 is bent to form a first side plate 101 and a second side plate 102. The first side plate 101 is attached to the bottom wall of the tank. Fasteners 40 are locked between the first side plate 101 and the bottom wall of the tank. A flexible bonding layer 20 is filled between the lower side of the second side plate 102 and the lower part of the tank, forming a weak bonding interface. Rigid foam strips are placed on the upper side of the second side plate 102. A rigid bonding layer 50 is fully filled between the rigid foam strips and the upper concrete, forming a rigid bonding interface that restricts relative displacement.

[0049] In this structure, the second side plate 102 acts as a physical "stress boundary layer," dividing the originally chaotic stress interface in two. Above it is a rigid, locked, strongly constrained area; below it is a flexible, slip-allowed, weakly released area. This asymmetrical structure allows the nodes to adaptively select the weakest link for stress release when subjected to external alternating loads, thereby protecting the integrity of the overall structure.

[0050] Furthermore, the rigid bonding layer 50 covers the upper end and outer surface of the rigid foam board strip, sealing the connection between the upper concrete and the second side panel 102. This covering structure prevents moisture from bypassing the rigid bonding layer 50 from above or the side and entering the back of the second side panel 102, achieving physical isolation. After hardening, the high-modulus colloid forms a "cap"-like sealing structure, tightly bonding the upper concrete to the second side panel 102.

[0051] To enhance the interfacial bond between the rigid adhesive layer 50 and the rigid foam board strips and prevent delamination due to material differences under long-term temperature fluctuations, a flexible reinforcing mesh layer is composited between the rigid foam board strips and the rigid adhesive layer 50. This flexible reinforcing mesh layer can be an alkali-free glass fiber mesh or a polyester fiber mesh, embedded within the structural adhesive, spanning the interface between the foam board and the adhesive, providing cross-interfacial tear resistance. When the adhesive undergoes slight shrinkage due to temperature changes, the mesh layer absorbs this stress, preventing micro-cracks at the interface. The mesh size of the reinforcing mesh layer should be moderate, typically between 5mm × 5mm and 10mm × 10mm, allowing the adhesive to penetrate the mesh and form an anchor without compromising the integrity of the adhesive due to an overly dense mesh.

[0052] As mentioned earlier, the upper edge of the trough is inclined outwards to form an outward-sloping water-facing surface. This structure not only increases the contact area between the upper rigid bonding layer 50 and the concrete (the inclined surface is larger than the straight surface), enhancing the anchoring force in the strongly constrained area, but more importantly, it utilizes the principle of gravity drainage. When water droplets fall on the inclined surface, their gravity can be decomposed into pressure perpendicular to the inclined surface and sliding force downwards along the inclined surface. The sliding force causes the water droplets to quickly detach from the interface, eliminating the potential for water film retention. This structure aligns with the "water curtain principle" in building physics, disrupting the stable boundary layer required for water adhesion by changing the interface inclination angle.

[0053] To ensure foolproof stress release, this application features a refined design for the weakly bonded interface, providing two specific implementation methods.

[0054] Form 1: Locally non-fully bonded structure based on isolation medium.

[0055] As in Embodiment 1, a release medium or a release film is applied to a predetermined area on the bottom surface of the second side panel 102. In practice, the predetermined area is usually the central area of ​​the bottom surface of the second side panel 102, accounting for a large proportion of the total bottom surface area (e.g., 60%-80%). After the release film is laid, the central area is completely unadhesive, relying solely on the flexible adhesive layer 20 at the edges for positioning. The stress model of this structure is very clear: when the flashing 10 is under tension, the edge adhesive deforms under stress, and the central area immediately detaches, forming a sliding pair similar to a "hinge," where the stress is absorbed by both the deformation of the flexible adhesive and the sliding of the interface. The thickness of the release film should be controlled between 0.05mm and 0.1mm; if it is too thin, it may be penetrated by the adhesive, and if it is too thick, it may affect the flatness and pressing of the second side panel 102.

[0056] Form 2: Point support system based on low-adhesion pads.

[0057] The weak bonding interface can also be formed by a number of low-bonding pads spaced apart on the bottom surface of the second side plate 102. There are gaps between adjacent low-bonding pads, and the flexible bonding layer 20 is partially bonded to the bottom surface of the second side plate 102 through the gaps.

[0058] The low-adhesion pads can be made of specially formulated low-tack silicone or weakly tack double-sided foam tape, and are attached to the bottom surface of the second side plate 102 in a matrix or quincunx pattern. When the second side plate 102 is pressed onto the flexible adhesive layer 20, the low-adhesion pads act as a supporting skeleton, maintaining the distance between the second side plate 102 and the lower part of the groove, preventing the flexible adhesive from being completely flattened and squeezed out. At the same time, the gaps between the pads allow the flexible adhesive to fill them, forming localized adhesion. Because the adhesion of the pads themselves is extremely low, and the bonding area is significantly reduced (limited to the pads and gaps), the overall interfacial adhesion is much lower than that of the rigid layer above. When deformation occurs, shear slippage easily occurs between the pads and the adhesive, and the gaps provide room for this slippage, preventing the adhesive from being forcibly torn due to lack of deformation. This structure performs particularly well in dealing with high-frequency micro-vibrations because the point support system can more flexibly adapt to small displacements in multiple directions.

[0059] In response to the special climatic conditions of outdoor roofs, this application adds multiple protective structures to the external form of the flashing 10 to comprehensively improve the anti-leakage capability of the joints.

[0060] First, the outer surface of the flashing 10 has a guiding slope inclined towards the steel gutter 300. In nature, wind and rain often carry a certain angle, directly hitting the wall surface. If the surface of the flashing 10 is horizontal, rainwater tends to accumulate there. With the guiding slope, the water will quickly flow towards the outer gutter using the component of gravity, reducing the residence time of water on the surface of the flashing 10 and lowering the probability of water molecules penetrating into the colloidal micropores. The guiding slope can be formed by directly pressing out the angle during the stamping of the flashing 10, or by adjusting the tilt angle of the flashing 10 during installation; the slope should generally not be less than 3%.

[0061] Secondly, the outdoor end of the flashing 10 is bent downwards to form a wind-absorbing fold (not shown in the attached diagram), extending into the interior of the steel gutter 300. In strong winds, a strong negative pressure zone (wind-driven force) is generated at the roof edge. This negative pressure can "suck" water up from the gutter, even pushing it over the edge of the flashing 10 and into the wall. The wind-absorbing fold, extending deep into the gutter, acts like a water-blocking wall, cutting off the path of water being drawn upwards by negative pressure. Simultaneously, the downward-extending fold alters the airflow direction, weakening the peak of the negative pressure at the end, resulting in excellent wind-blown and backflow prevention. The wind-absorbing fold should extend at least 50mm below the highest water level in the gutter to ensure that backflow does not occur even if the gutter is full due to heavy rain.

[0062] Finally, the water-facing surface and outer surface of the flashing 10 are provided with a hydrophobic coating (not shown in the attached diagram). The hydrophobic coating can be made of fluorinated resin or nano-silica coating, which has extremely low surface energy and exhibits a "lotus effect" similar to that of a lotus leaf. Water droplets falling on the coating will remain spherical and roll off easily, not only carrying away surface dust but also preventing the formation of a water film and capillary action. Even if there is a slight risk of water seepage, the hydrophobic coating can prevent moisture from wetting and adhering to the metal surface at a physicochemical level.

[0063] In summary, the flashing construction method and flashing structure for the interface between concrete walls and steel roofs provided in this application have the following significant advantages: (1) Through the innovative “strong on top and weak on bottom” asymmetric bonding design and L-shaped layered structure, uncontrollable destructive cracks are transformed into controllable pre-set slip surfaces, which thoroughly protect the most vulnerable cement-concrete bonding surface and realize the leap from “passive plugging” to “active drainage” waterproofing concept.

[0064] (2) The anchoring method of the first side plate 101 with lateral wall nailing greatly improves the wind resistance, and the fastener 40 is deeply hidden inside the groove, avoiding the hidden danger of failure caused by rust, and ensuring the mechanical stability of the node throughout the entire building life cycle.

[0065] (3) The process of applying flexible adhesive first and then pressing the plate ensures the density of the bottom adhesive layer; the rigid foam board strips serve as backing support, ensuring the fullness of the upper structural adhesive, greatly reducing the sensitivity of the worker's construction method to the final quality, and improving the uniformity of the project quality.

[0066] All-weather protection system: Through a multi-level structure of outward-sloping water-facing surface, guide slope, windproof and suction-proof folds and hydrophobic coating, it comprehensively resists gravity water, wind-induced backflow water and capillary water penetration, ensuring that it maintains excellent waterproof performance even in extreme weather conditions, extending the maintenance cycle and reducing the total life cycle maintenance cost.

[0067] The above are only some or preferred embodiments of this application. Neither the text nor the drawings should limit the scope of protection of this application. All equivalent structural transformations made using the content of this application's specification and drawings under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A construction method for flashing at the interface of a concrete wall and a steel roof, characterized in that, Includes the following steps: S1, create and clean the groove at the interface between the concrete wall and the steel roof; S2, a flashing plate is provided, the head of which is bent to form a first side plate and a second side plate; a flexible adhesive layer is applied to the lower part of the tank; the first side plate is attached to the bottom wall of the tank and locked with fasteners, and the second side plate is pressed on the flexible adhesive layer to form a flexible adhesive interface that allows relative sliding; S3, rigid foam strips are bonded to the upper side of the second side panel using double-sided adhesive. S4. A rigid bonding layer is applied between the rigid foam board strip and the upper concrete body to form a rigid bonding interface that restricts relative displacement.

2. The construction method for flashing at the interface of concrete wall and steel roof according to claim 1, characterized in that, The flexible adhesive layer uses a low-modulus sealing material, and the rigid adhesive layer uses a high-modulus weather-resistant sealing material.

3. The construction method for flashing at the interface of concrete wall and steel roof according to claim 1, characterized in that, In step S2, before applying the flexible adhesive layer, a release medium is applied or a release film is laid in a local area on the bottom surface of the second side plate so that a local non-full adhesive structure is formed between the bottom surface of the second side plate and the flexible adhesive layer.

4. The construction method for flashing at the interface of concrete wall and steel roof according to claim 1, characterized in that, The fasteners are arranged in an alternating pattern along the length of the first side plate, and the heads of the fasteners are recessed into the surface of the first side plate.

5. A flashing structure at the interface of a concrete wall and a steel roof, characterized in that, include: A groove set in a concrete wall; The flashing plate has its head bent to form a first side plate and a second side plate, with the first side plate attached to the bottom wall of the trough. Fasteners are used to secure the first side plate to the bottom wall of the groove. A flexible adhesive layer is filled between the lower side of the second side plate and the lower part of the groove to form a weak adhesive interface; Rigid foam strips are provided on the upper side of the second side plate; A rigid bonding layer is fully filled between the rigid foam strips and the upper concrete body to form a strong bonding interface.

6. The flashing structure at the interface of concrete wall and steel roof according to claim 5, characterized in that, The rigid adhesive layer covers the upper end face and outer side face of the rigid foam board strip and seals the connection between the upper concrete body and the second side plate.

7. The flashing structure at the interface of concrete wall and steel roof according to claim 5, characterized in that, A flexible reinforcing mesh layer is composited between the rigid foam board strip and the rigid adhesive layer.

8. The flashing structure at the interface of concrete wall and steel roof according to claim 5, characterized in that, The upper edge of the tank is inclined outwards to form an outward-sloping water-facing surface.

9. The flashing structure at the interface of concrete wall and steel roof according to claim 5, characterized in that, The outdoor end of the flashing is bent downward to form a windproof and suction-proof edge, which extends into the steel gutter; the outer surface of the flashing is provided with a guide slope that is inclined towards the steel gutter.

10. The flashing structure at the interface of concrete wall and steel roof according to claim 5, characterized in that, The flashing has a hydrophobic coating on its water-facing surface and outer surface.

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