A repair process for gable roof slabs of hip-roof buildings

Abstract

A process for repairing the gable roof of a hip-and-gable building is characterized by the following steps: 1. Repairing the wooden base layer; 2. Applying protective plaster; 3. Applying two layers of hemp and six layers of plaster; 4. Applying three coats of pigment paint and one coat of varnish; 5. Making and installing a metal gable roof made of finely carved aluminum plate; 6. Fixing with round nails; 7. Restoring the glazed tile ridge and roof tiles; wherein, the method for making the metal gable roof includes: (1) splicing metal aluminum materials and polishing and finely carving the joints; (2) applying an epoxy fluorocarbon composite coating; the coating has a three-layer structure, consisting of a base layer, an intermediate layer and a cover layer, wherein the base layer is made of an epoxy resin type primer containing epoxy resin, epoxy modified filler and isocyanate curing agent, the intermediate layer is made of a composite two-component intermediate paint containing epoxy resin, fluorocarbon resin, polyamide resin and aliphatic polyamine curing agent, and the cover layer is prepared by a two-component fluorocarbon topcoat.

Description

Technical Field

[0001] This invention belongs to the field of ancient building technology, specifically relating to a repair process for the gable roof of a hip-roofed building. Background Technology

[0002] Chinese traditional architecture, as an ancient and independent architectural system, has evolved over thousands of years, developing unique architectural forms. With the progress of the times, the importance of restoring ancient buildings has become increasingly prominent. However, with the continuous emergence of new materials and technologies, how to apply these new materials and technologies to the restoration of Chinese traditional architecture has become an urgent problem to be solved. It is worth noting that the methods of restoring traditional Chinese buildings differ significantly from those of new construction.

[0003] The gable panel in a hip-roof building is a unique decorative and structural component of traditional Chinese architecture. Located within the triangular area at the top of the gable walls on both sides of the building (the "gable"), it serves both functional and aesthetic purposes. The gable (both sides) of a hip-roof building is formed by the intersection of the vertical "gable walls" and the sloping "roof," creating a triangular area (gable). The gable panel is the wooden or decorative panel covering this area. The gable panel encloses the gable space, concealing the internal beams, rafters, and other structural elements, providing protection from wind, rain, and dust. It is typically decorated with painted, carved, or openwork patterns (such as hanging fish or decorative motifs) to reflect social status and artistry.

[0004] For the gable roofs of ancient buildings, the gable roofs of ancient buildings often suffer from problems such as fading paint, peeling, and damaged carvings due to years of disrepair. This is because traditional painted paints fade due to ultraviolet radiation and acid rain, and the base layer (substrate) cracks, decays, and becomes hollow and falls off. Faced with this problem, the applicant decided to adopt traditional repair methods to restore the base layer of the gable roof. On this basis, an innovative method was adopted to use an externally intricately carved aluminum plate and spray a protective paint to better protect the original old gable roof. However, this technology has two main problems: (1) the overall quality of the metal gable roof is relatively high, so how to solve the problem of whether the gable roof is firm after installation; (2) in practical application, it was found that the traditional fluorocarbon paint has poor adhesion to the intricately carved aluminum plate and is easy to fall off over time. This is because existing metals, such as aluminum plates, have smooth surfaces, making it easy for ordinary coatings to peel off, especially single-component paint films. Fluorocarbon coatings have low surface energy, heat resistance, chemical resistance, and excellent weather resistance, but their adhesion to metals is extremely poor. Through joint research with a university chemistry laboratory, we also found that while epoxy resin paint films have relatively outstanding adhesion, their weather resistance is poor. How to solve the adhesion and durability problems of colored fluorocarbon paint with intricately carved aluminum plates is also a technical challenge. Summary of the Invention

[0005] This invention relates to a repair process for the gable board of a hip roof building, comprising the following steps: (1) repairing the wooden base layer; (2) applying protective plaster; (3) applying two layers of hemp and six layers of plaster; (4) applying three coats of paint and one coat of varnish; (5) fabricating and installing the metal gable board made of finely carved aluminum plate; (6) fixing with round nails; (7) restoring the gable board and ridge.

[0006] Furthermore, it also includes: 8. Gold plating on metal gable panels.

[0007] Furthermore, step 7 includes restoring the roof tiles.

[0008] The manufacturing method of the metal gable panel includes: 1) splicing metal aluminum materials and grinding and fine carving the joints; 2) coating the surface of the metal aluminum materials after step 1) with an epoxy fluorocarbon composite coating; the epoxy fluorocarbon composite coating has a three-layer structure, consisting of a base layer, an intermediate layer and a cover layer, wherein the base layer is made of an epoxy resin type primer containing epoxy resin, epoxy modified filler and isocyanate curing agent, the particle size of the epoxy modified filler is 1-40μm and the coating thickness is 60-80μm; the intermediate layer is made of a composite two-component intermediate paint containing epoxy resin, fluorocarbon resin, polyamide resin and aliphatic polyamine curing agent, and the cover layer is prepared by a two-component fluorocarbon topcoat.

[0009] Before installing the metal gable panel, a groove with a width of 30-40mm and a depth of 25-35mm is pre-drilled on the inner side of the gable panel, preferably with a width of 35mm and a depth of 30mm. This design not only ensures the accuracy of the gable panel installation but also enhances the bonding force between the two through physical structure, effectively preventing displacement or loosening caused by material differences. The gable panel can be made of wood.

[0010] After the metal gable slab is installed, a pine wood support, 90-110mm long, 40-60mm wide, and 30-50mm thick, is installed every 0.8-1.2 meters on the footings and securely fixed with round nails. This innovative reinforcement measure significantly improves the overall stability of the gable slab, especially in the face of natural factors such as wind and earthquakes, effectively dispersing stress and preventing displacement or loosening caused by installation problems. The footings are located directly below the gable slab, and the two connect perpendicularly to form a "T"-shaped support structure.

[0011] At the joints between the metal gable panels and the ridge purlins and eaves purlins, 80mm round nails are used for precise fixing to ensure a tight, seamless fit between the gable panels and the main structure. This step is crucial not only for structural stability but also for ensuring a neat and aesthetically pleasing building appearance. The ridge purlin (or ridge beam) is a horizontal wooden member located at the highest point of the roof, below the ridge, and serves as the roof's "main beam." The eaves purlins (or eaves purlins) are horizontal purlins located between the ridge purlins and the outermost purlins. They are classified by height as upper, middle, and lower purlins, and their function is to distribute the roof load, transferring the weight to the beams or columns.

[0012] Among them, gilding metal pediments involves applying yellow glue to the pediment and surrounding decorative components, followed by brushing on gold glue and then gilding. The use of this traditional technique not only enhances the rust resistance of the components but also gives the building a magnificent, solemn, and elegant visual effect, perfectly blending traditional aesthetics with modern technology.

[0013] This invention also relates to an epoxy fluorocarbon composite coating having a three-layer structure, consisting of a base layer, an intermediate layer, and a masking layer, wherein:

[0014] (1) Base layer, the base layer is made of epoxy resin type primer, the primer contains component A and component B, by mass parts, wherein component A includes: 50-60 parts of epoxy resin, 5-15 parts of modified filler, 1-10 parts of additives, and solvent; component B includes: 5-15 parts of isocyanate curing agent; wherein the modified filler is obtained by modifying silica with epoxy functional silane coupling agent, the particle size of the modified filler is 1-40μm, wherein the weight ratio of particle size (30-40)μm: (10-30)μm: (1-10)μm is (2-4): (0.5-1.5): (0.5-1.5), and the coating thickness is 60-80μm;

[0015] (2) Intermediate layer, the intermediate layer is made of composite two-component intermediate paint, containing component A and component B. Component A contains the following components by weight: 30-40 parts epoxy resin, 20-25 parts fluorocarbon resin, and 0.5-1.5 parts silane coupling agent KH-560. Component B includes: 5-10 parts curing agent, wherein the curing agent includes polyamide resin and aliphatic polyamine. The coating thickness is 40-60μm.

[0016] (3) Covering layer, which is prepared by a two-component fluorocarbon topcoat with a coating thickness of 60-80μm;

[0017] The weight ratio of component A to component B is 10:(0.5-1.5);

[0018] The modified filler is epoxy-modified silica, which is obtained by modifying silica with an epoxy-functionalized silane coupling agent. The epoxy-functionalized silane coupling agent is selected from at least one of γ-glycidoxypropyltrimethoxysilane, 2-(3-4-epoxycyclohexyl)ethyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, (3-glycidoxypropyl)methyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane. The modified filler has a particle size of 180-300 mesh, preferably 200 (75 μm)-250 mesh (75 μm).

[0019] The additives include: dispersant: 1.4-2.6 parts, defoamer: 0.2-0.3 parts, leveling agent: 0.2-0.3 parts, anti-sagging agent: 2.0-3.0 parts, and silane coupling agent: 0.5-1.0 parts;

[0020] The epoxy resin is a glycidyl ether epoxy resin, and more specifically, E-3, E-42, E-44, E-20, and E-51.

[0021] The solvents include propylene glycol methyl ether, propylene glycol methyl ether acetate, methyl isobutyl ketone, xylene BU, methyl ethyl ketone, and methyl ethyl ketone. More preferably, the solvents are propylene glycol methyl ether acetate and methyl ethyl ketone, with a mass ratio of (2-4):1.

[0022] Curing agent: polyisocyanate, specifically isophorone diisocyanate, adduct of TDI and trimethylolpropane, adduct of HDI and trimethylolpropane, trimethylhexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

[0023] Polyisocyanate curing agents can also be used as sealants to seal components A and B, thereby mixing them to form a single-component coating. Sealants can be methyl ethyl ketone oxime, cyclohexane oxime, phenol, p-tert-butylphenol, cresol, ethyl acetoacetate, or methyl acetoacetate.

[0024] The curing agent should not contain too much isocyanate. If too much isocyanate is used, the cross-linking density will be high after curing with polyisocyanate, but the adhesion to the metal will be low, and it will be easy to peel off when bent.

[0025] (2) Intermediate layer, the intermediate layer is made of composite two-component intermediate paint, the intermediate paint contains component A and component B, component A contains the following components by mass: 30-40 parts epoxy resin, 20-25 parts fluorocarbon resin, 10-30 parts inorganic filler, 0.5-1.5 parts silane coupling agent KH-560, 0.3-0.5 parts dispersant, 0.2-0.3 parts defoamer, and 10-30 parts solvent, component B is: 5-10 parts curing agent.

[0026] The curing agent consists of 6-10 parts polyamide resin, 1-3 parts aliphatic polyamine, 0.1-0.3 parts accelerator, and solvent.

[0027] The polyamide resin can be Aradur 450, and the aliphatic polyamine can be triethylenetetramine (TETA), polyether diamine (D230, D400), or polyether triamine (T403). As a curing agent, the polyamide resin can improve the toughness of the intermediate layer, and when used in conjunction with aliphatic polyamines, it enhances the rapid crosslinking and curing ability of the epoxy resin.

[0028] The solvents in component A include methyl ethyl ketone, xylene, and propylene glycol methyl ether acetate; the curing agent can be a polyamide resin, such as Aradur 450.

[0029] The inorganic filler can be rutile titanium dioxide, mica powder, calcium carbonate, or talc powder, with a specific weight ratio of (10-14):(2-6):(2-6):(2-6). Among them, titanium dioxide enhances hiding power and weather resistance, mica powder improves impermeability, and calcium carbonate reduces coating costs.

[0030] The silane coupling agent KH-560 improves the compatibility of epoxy resin and fluorocarbon resin, and also enhances the adhesion between the intermediate layer and the base layer and the cover layer.

[0031] The epoxy resin is one or a combination of bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenolic glycidyl ether, and aliphatic glycidyl ether. The amount of fluorocarbon resin used should not be too high, as this will lead to a decrease in the compatibility between the fluorocarbon resin and the epoxy resin.

[0032] (3) Covering layer, the covering layer is prepared from a two-component fluorocarbon topcoat, the topcoat comprising component A and component B, component A comprising the following components by mass: FEVE fluorocarbon resin: 45.0-65.0 parts, dispersant: 1.4-2.0 parts, expanded vermiculite 10-15 parts, inorganic filler: 5.0-10.0 parts, inorganic pigment: 8.0-12.0 parts, defoamer: 0.2-0.3 parts, leveling agent: 0.2-0.3 parts, matting agent: 2.0-5.0 parts, solvent 2-20 parts; component B is hexamethylene diisocyanate trimer 8-15 parts.

[0033] Furthermore, the expanded vermiculite is 80-120 mesh, the inorganic fillers are rutile titanium dioxide, heavy calcium carbonate, and talc; the inorganic pigments are iron oxide red and iron oxide black; the coating thickness is 60-80 μm; and the solvents include butyl acetate, propylene glycol methyl ether acetate, and methyl isobutyl ketone.

[0034] Technical effects:

[0035] (1) This invention innovatively introduces a multi-layered composite epoxy fluorocarbon coating for protecting metal gable panels in the gable panel restoration process. Simultaneously, a pre-reserved groove on the inner side of the wooden gable panel ensures not only the accuracy of the gable panel installation but also, after the metal gable panel is installed, a pine wood support is placed on the footrest and firmly fixed with round nails. Through this restoration process, cultural heritage is preserved while significantly improving the durability and safety of the building. This restoration process successfully solves the key problem of gable panel protection in hip-roofed buildings, restoring the original appearance of the ancient building. This restoration plan not only effectively protects the original cultural relics but also authentically restores the style of the wooden gable, giving the ancient building new vitality.

[0036] (2) This invention employs a multi-layer composite epoxy fluorocarbon coating, achieving low-cost anti-corrosion and color protection coating for aluminum plates. This coating combines the advantages of good adhesion and low cost of epoxy resin with the excellent weather resistance, acid and alkali resistance, and stain resistance of fluorocarbon resin. The key to this coating lies in the use of isocyanate-type curing agents in the bottom layer, which differ from commonly used aliphatic polyamines and polyamides. Isocyanate-type curing agents only undergo cross-linking and curing reactions with the hydroxyl groups in epoxy resin, while retaining the epoxy groups. Therefore, the epoxy functional groups on the surface of the modified filler are retained in the base layer. At the same time, more than half of the modified filler is 30-40 micrometers in size, and the base layer coating thickness is 60-80 μm. Due to the large particle size of the modified filler, a considerable portion of the modified filler protrudes from the paint film surface, forming a certain roughness, while retaining the epoxy functional groups. The presence of fillers with a particle size of 1-30 μm fills the gaps between the large-particle fillers, reducing the impact of excessively large filler particle size on the density of the paint film. Together, they improve the impermeability. During the curing process of the intermediate layer composite coating, the curing agent used is polyamide resin and aliphatic polyamine. Its active hydrogen reacts not only with the epoxy resin of the intermediate layer but also with the epoxy groups of the epoxy resin on the primer surface and the modified filler. In this way, the modified filler acts as an anchor between the base layer and the intermediate layer, significantly improving their adhesion. Therefore, the epoxy-functionalized silane coupling agent on the surface of the modified filler not only improves the compatibility between the filler and the resin but, more importantly, forms a chemical cross-link with the intermediate layer, significantly improving adhesion and thus enhancing water resistance and acid / alkali resistance.

[0037] (3) The intermediate layer is a composite coating of epoxy resin and fluorocarbon resin as a transition layer, which not only increases the compatibility with the epoxy coating of the base layer, but also improves the compatibility of the fluorocarbon covering layer. At the same time, the fluorocarbon resin in the intermediate layer further improves the acid and alkali resistance and weather resistance of the overall composite coating, while the addition of KH560 on the surface also improves the compatibility between epoxy resin and fluorocarbon resin. Detailed Implementation

[0038] Example 1

[0039] The repair process of the gable board of a hipped building is as follows: 1. Repair the wooden base layer; 2. Apply protective plaster; 3. Apply two layers of hemp and six layers of plaster; 4. Apply three coats of paint and one coat of varnish; 5. Make and install the metal gable board made of finely carved aluminum plate; 6. Fix with round nails; 7. Restore the gable board and ridge; 8. Apply gold leaf to the metal gable board; The production method of the metal gable board includes: (1) Grinding and fine carving the splicing and butt joints of the metal aluminum material; (2) Coating with epoxy fluorocarbon composite coating; Among them, before the metal gable board is installed, a groove with a width of 35mm and a depth of 30mm is reserved on the inner side of the wooden gable board. The epoxy fluorocarbon composite coating is made in the manner of Example 2.

[0040] It should be noted that the gable board (also known as the "wind-bracing board") is a strip of wooden board installed on the top of the gable wall of a hip, overhanging, or hip-and-gable roof building. It is located at the eaves on both sides of the roof, closely attached to the ends of the purlins (such as eave purlins and gable purlins), and connected to the tile surface and the ridge. The ridge is a horizontal ridge unique to hip-and-gable roofs, located at the junction of the gable board and the lower roof surface (such as the spire or drip edge), extending horizontally along the vertical direction of the gable.

[0041] Example 2: Preparation of epoxy fluorocarbon composite coating A

[0042] The epoxy fluorocarbon composite coating has a three-layer structure, consisting of a base layer, an intermediate layer, and a masking layer. Among them, (1) the base layer is made of epoxy resin primer, which contains component A and component B. Component A includes: 60 parts epoxy resin, 12 parts modified filler, and 5 parts additives, specifically: 2 parts dispersant, 0.2 parts defoamer, 0.3 parts leveling agent, 2.0 parts anti-sagging agent, and 0.5 parts silane coupling agent; 23 parts solvent. Component B consists of: 10 parts of isocyanate curing agent; wherein the modified filler is obtained by modifying silica with KH-560, and the weight ratio of particle size (30-40)μm:(10-30)μm:(1-10)μm in the modified filler is 2.5:1:1, and the coating thickness is 60μm; the epoxy resin is E-42, the curing agent is isophorone diisocyanate; the solvent is propylene glycol methyl ether acetate and methyl ethyl ketone, with a mass ratio of 3:1.

[0043] (2) The intermediate layer is made of a composite two-component intermediate paint, containing component A and component B. Component A contains the following components by mass: 35 parts epoxy resin, 25 parts fluorocarbon resin, 1 part silane coupling agent KH-560, 10 parts inorganic filler (rutile titanium dioxide), 2 parts mica powder, 2 parts calcium carbonate, 2 parts talc powder, and 23 parts solvent. Component B includes: 6 parts curing agent, which is composed of polyamide resin and triethylenetetramine in a mass ratio of 2:1, with a coating thickness of 50μm; the solvent is propylene glycol methyl ether acetate and methyl ethyl ketone in a mass ratio of 2:1.

[0044] (3) The covering layer is prepared by a two-component fluorocarbon topcoat with a coating thickness of 70 μm. The covering layer is prepared by a two-component fluorocarbon topcoat, which includes component A and component B. Component A includes the following components by mass: FEVE fluorocarbon resin: 50 parts, expanded vermiculite: 12 parts, inorganic filler rutile titanium dioxide: 8 parts, inorganic pigment iron oxide red: 10 parts, dispersant: 1.5 parts, defoamer: 0.2 parts, leveling agent: 0.3 parts, matting agent: 3 parts, solvent: 15 parts; component B is hexamethylene diisocyanate trimer: 10 parts, and the solvent is butyl acetate and propylene glycol methyl ether acetate, with a mass ratio of 1:1.

[0045] The epoxy resin primer, composite two-component intermediate paint and two-component fluorocarbon topcoat are prepared into finished coatings according to the common coating mixing process. The coatings are then applied to the surface of an aluminum plate substrate, and an aluminum plate with an epoxy fluorocarbon composite coating is obtained by sequential coating and curing.

[0046] Example 3: Preparation of epoxy fluorocarbon composite coating B

[0047] The modified filler in the epoxy resin primer of Example 1 was replaced with conventional unmodified silica, and everything else was exactly the same as in Example 1. A three-coating and curing process was used to obtain an aluminum plate covered with a 180μm coating.

[0048] Example 4: Preparation of epoxy fluorocarbon composite coating C

[0049] The epoxy resin primer from Example 1 was used instead of the composite two-component intermediate paint and two-component fluorocarbon topcoat from Example 1. Everything else was exactly the same as in Example 1. A three-coating and curing process was used to obtain an aluminum plate covered with a 180μm coating.

[0050] Example 5: Preparation of epoxy fluorocarbon composite coating D

[0051] The intermediate layer composite two-component intermediate paint of Example 1 was used instead of the epoxy resin primer and two-component fluorocarbon topcoat in Example 1. Everything else was exactly the same as in Example 1. A three-coating and curing process was used to obtain an aluminum plate covered with a 180μm coating.

[0052] Example 6: Preparation of epoxy fluorocarbon composite coating E

[0053] The two-component fluorocarbon topcoat of Example 1 was used instead of the epoxy resin primer and composite two-component intermediate paint in Example 1. Everything else was exactly the same as in Example 1. A three-coating and curing process was used to obtain an aluminum plate covered with a 180μm coating.

[0054] Performance testing

[0055] Adhesion was tested according to GB / T9286-2021 (cross-cut test).

[0056] The aging resistance was tested using an artificial accelerated aging test method, according to the requirements of Cycle A in GB / T 1865-2009 "Artificial Climate Aging and Artificial Radiation Exposure to Filtered Xenon Arc Radiation". The results were evaluated from the color change level according to GB / T 1766 "Rating Method for Aging of Paint and Varnish Coatings". The test time was 2000 hours.

[0057] The salt spray resistance test was conducted in accordance with GB / T 1771-2007 "Determination of resistance to neutral salt spray of paints and varnishes". The evaluation criterion was the time required to observe phenomena such as rust spots, blistering, and peeling of the paint film.

[0058]

[0059] As shown in the table above, the composite coating of the present invention has good adhesion to aluminum plates, and its corrosion resistance and durability are greatly improved.

Claims

1. A repair process for the gable slab of a hip-and-gable roof building, characterized in that, The steps include: (1) repairing the wooden base; (2) applying protective plaster; (3) applying two coats of hemp and six coats of plaster; (4) applying three coats of paint and one coat of varnish; (5) making and installing the metal gable slab made of finely carved aluminum plate; (6) fixing with round nails; (7) restoring the gable slab and ridge; among which, the method of making the metal gable slab includes: 1) Grinding and fine carving are performed on the spliced ​​aluminum materials and the joints; 2) Coat the surface of the aluminum metal material treated in step 1) with an epoxy fluorocarbon composite coating; the epoxy fluorocarbon composite coating has a three-layer structure, consisting of a base layer, an intermediate layer, and a cover layer. The base layer is made of an epoxy resin-type primer containing epoxy resin, epoxy modified filler, and isocyanate curing agent. The epoxy resin in the base layer is a glycidyl ether epoxy resin. The particle size of the epoxy modified filler is 1-40 μm, and the coating thickness is 60-80 μm. The intermediate layer is made of a composite two-component intermediate paint containing a curing agent composed of epoxy resin, fluorocarbon resin, polyamide resin, and aliphatic polyamine. The epoxy resin in the intermediate layer is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenolic glycidyl ether, and aliphatic glycidyl ether. The cover layer is prepared by a two-component fluorocarbon topcoat.

2. The repair process for the gable roof slab of a hip-and-gable building according to claim 1, characterized in that, Also includes: (8) Gold leafing on metal gable panels.

3. The repair process for the gable roof slab of a hip-and-gable building according to claim 1, characterized in that, Before installing the metal gable panel, a groove with a width of 30-40mm and a depth of 25-35mm should be reserved on the inside of the gable panel.

4. The repair process for the gable roof slab of a hip-and-gable building according to claim 1, characterized in that, After the metal gable board is installed, a pine wood support with a length of 90-110mm, a width of 40-60mm, and a thickness of 30-50mm should be installed on the footing every 0.8-1.2 meters, and it should be firmly fixed with round nails.

5. The repair process for the gable roof slab of a hip-and-gable building according to claim 1, characterized in that, At the joints between the metal gable slab and the ridge purlin and main purlin, 80mm round nails are used for precise fixing to ensure that the metal gable slab fits tightly with the main structure without gaps.

6. The repair process for the gable roof slab of a hip-and-gable building according to claim 2, characterized in that, Gilding of metal gable panels involves applying yellow glue to the metal gable panel and surrounding decorative components, then brushing on gold glue and gilding.

7. The repair process for the gable roof slab of a hip-and-gable building according to claim 1, characterized in that, The base layer is made of epoxy resin primer, which contains component A and component B. By mass, component A includes 50-60 parts epoxy resin, 5-15 parts modified filler, 1-10 parts additives, and solvent; component B includes 5-15 parts isocyanate curing agent. The modified filler is obtained by modifying silica with epoxy functional silane coupling agent. The particle size of the modified filler is 1-40 μm, and the weight ratio of particle size (30-40) μm: (10-30) μm: (1-10) μm is (2-4): (0.5-1.5): (0.5-1.5). The coating thickness is 60-80 μm.

8. The repair process for the gable roof slab of a hip-and-gable building according to claim 1, characterized in that, The intermediate layer is made of a composite two-component intermediate paint, containing component A and component B. Component A contains the following components by weight: 30-40 parts epoxy resin, 20-25 parts fluorocarbon resin, and 0.5-1.5 parts silane coupling agent KH-560. Component B includes 5-10 parts curing agent, which includes polyamide resin and aliphatic polyamine. The coating thickness is 40-60 μm.

9. The repair process for the gable roof slab of a hip-and-gable building according to claim 1, characterized in that, The two-component fluorocarbon topcoat comprises component A and component B. Component A comprises the following components by weight: FEVE fluorocarbon resin: 45.0-65.0 parts, dispersant: 1.4-2.0 parts, expanded vermiculite: 10-15 parts, inorganic filler: 5.0-10.0 parts, inorganic pigment: 8.0-12.0 parts, defoamer: 0.2-0.3 parts, leveling agent: 0.2-0.3 parts, matting agent: 2.0-5.0 parts, and solvent: 2-20 parts; component B comprises 8-15 parts of hexamethylene diisocyanate trimer.

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