Construction method of outer wall external thermal insulation adhesive anchor support

Abstract

The invention provides a construction method of an outer wall external thermal insulation adhesive anchor support, and belongs to the technical field of building thermal insulation construction. According to the method, a bonding, anchoring and supporting triple synergistic fixing system serves as a core, traditional single fixing limitation is broken through, a modified glass bead composite board serves as a heat preservation core and is matched with special bonding mortar, a mechanical anchoring part and an aluminum alloy keel supporting and hanging part to form a stable structure, inorganic colored mortar is sprayed on a surface layer, and a heat preservation, fire prevention and decoration integrated system is constructed. The construction process comprises the following steps: cleaning and repairing a base layer, constructing a waterproof leveling layer, releasing a datum line, mounting a supporting and hanging piece, fully adhering the composite board and overlapping the composite board in a staggered joint manner, implanting an anchoring piece, plastering and embedding a net for resisting crack, and spraying a facing layer. The problems of hollowing, cracking, low fireproof grade, weak high-rise wind uplift resistance and other pain points of a traditional system are solved, the heat preservation and wind resistance performance is excellent, and the construction period is greatly shortened. The system is suitable for various base layers, is suitable for newly-built and existing building transformation, achieves A-level fire prevention and high-standard energy saving, has remarkable benefits and is wide in application prospect.

Description

Technical Field

[0001] This invention belongs to the field of building insulation construction technology, and relates to external wall insulation, particularly a method for installing external wall insulation adhesive anchors. Background Technology

[0002] External wall insulation technology, as one of the core technologies for building energy conservation, has advantages such as good insulation effect, no thermal bridge, and dew point located inside the wall, and has been widely used in building engineering. At present, the mainstream construction process for external wall insulation in the market is mainly a thin plastering system, which uses special bonding mortar to stick the insulation board to the base wall, fixes it with a small number of anchors, and then applies a finishing mortar and lays a mesh cloth.

[0003] However, traditional thin-plaster systems have many technical drawbacks: First, the fixing method is singular, relying only on bonding mortar and a small number of anchors, which can easily lead to hollowing, cracking, or even detachment in high-rise buildings or areas with complex climates, posing a high safety risk; second, the fire resistance of the insulation materials is insufficient, with most organic insulation materials only meeting the Class B fire resistance standard, which is insufficient to meet the fire protection requirements of high-rise and super high-rise buildings; third, the construction cycle is long, with a large amount of wet work on site, significantly affected by weather, and high maintenance costs in the later stages; fourth, the durability is poor, with the organic finishing layer prone to aging and the insulation board prone to shrinkage and deformation, resulting in a system lifespan shorter than the building structure lifespan.

[0004] While some existing improved technologies, such as prefabricated integrated insulation and decoration systems, have improved construction efficiency, they are costly and have poor adaptability, making it difficult to meet the needs of existing building renovations. Hanging systems often rely on a single hanging structure, lacking multiple layers of protection, and their safety still needs improvement. Therefore, developing a construction method for external wall insulation that combines high safety, excellent fire resistance, high construction efficiency, and good durability is of significant practical importance. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a construction method for external wall insulation using adhesive anchor brackets. The technical problem this invention aims to solve is to address the issues of easy delamination and detachment, poor fire resistance, and long construction period associated with traditional processes by combining a triple fixing system of adhesive, anchor, and bracket with inorganic materials.

[0006] The objective of this invention can be achieved through the following technical solutions: An external wall insulation adhesive anchor bracket construction method, based on a triple fixing system of adhesive, anchor, and bracket, uses modified vitrified microsphere composite board as the core insulation material, combined with special adhesive mortar, mechanical anchors, and horizontal aluminum alloy keel brackets to form a fixing structure, and an inorganic colored mortar finishing layer is applied to the surface. The method specifically includes the following steps: Step 1: Base treatment. Thoroughly clean the surface of the base wall, removing dust, oil, laitance, and other debris. Check the flatness of the wall surface and repair any defects such as honeycomb, pitting, or misalignment. After removing the misaligned layer, fill it with cement mortar. Repair any missing edges or corners in advance. After the base treatment is qualified, spray a full coat of waterproof mortar to form a waterproof leveling layer. Add another coat of waterproof mortar 300mm above and below each structural connection.

[0007] Step 2: Lay out the baseline. Based on the building facade design drawings and insulation construction requirements, measure control points from the electrical shaft according to the standard floor height, setting one standard control point every three floors; use a level to transfer the control points to the outer surface of the exterior wall to form horizontal control points; pop up vertical and horizontal control lines on the wall, with a spacing of no more than 3m between control lines; lay out a vertical line separately at the corner of each facade, and calibrate the vertical lines with a theodolite to ensure that the verticality deviation is no more than 2mm / 5m.

[0008] Step 3: Install the horizontal aluminum alloy keel brackets. Determine the installation position of the brackets according to the horizontal control line, and align the bottom of the horizontal aluminum alloy keel brackets with the horizontal baseline. Use an electric hammer to drill holes into the base wall along the holes of the brackets. The drilling diameter should match the size of the expansion sleeve bolts, and the drilling depth should be 10mm greater than the bolt insertion depth. Insert the expansion sleeve bolts and tighten them with a wrench to firmly fix the brackets to the base wall. The brackets should be arranged along the entire length of the upper and lower ring beams of each floor, with the spacing between adjacent brackets not exceeding 600mm.

[0009] Step 4: Prepare the mortar. Prepare the special bonding mortar and the inorganic colored mortar separately. Use a handheld electric mixer to mix them. Add water to the special bonding mortar at a weight ratio of 1:4.5, and add water to the inorganic colored mortar at a weight ratio of 1:5. Add water while mixing for at least 5 minutes to ensure that the mortar is fully mixed and uniform. The consistency should be such that it can be formed into a ball when squeezed in the hand, but crumbles when dropped. After the mortar is prepared, let it stand for 5 minutes, and stir it again before use. The prepared mortar should be used within 2 hours. Mortar that has exceeded the usage time should not be used.

[0010] Step 5: Adhere the modified vitrified microsphere composite board. Before construction, prepare a layout plan based on the dimensions of the exterior wall facade to optimize the composite board layout and reduce cutting waste. The modified vitrified microsphere composite board is 300mm*600mm in size. Cut it with a special cutting machine according to the layout plan to ensure straight and square cuts. The composite board is laid horizontally along its length, with the vertical joints of the upper and lower rows staggered by 1 / 2 board length, and the minimum stagger in any local area should not be less than 200mm. At corners, vertical staggered joints are used to ensure that the corners are straight and complete along the entire height of the building. The composite board is adhered using the full-adhesion method. Apply special adhesive mortar evenly to the back of the composite board, with a mortar thickness of 5-8mm. Adhesive mortar is strictly prohibited from being applied to the sides of the board. Align the composite board with the control line and adhere it to the base layer. Gently press and knead to ensure the mortar is fully applied, and adjust the position of the composite board until it is flat and firm. For parts such as scaffolding wall ties that protrude from the wall and need to be removed, reserve openings for the entire board. Finish the work after the wall ties are removed.

[0011] Step 6: Install anchors. After the composite panels are pasted and left to stand for 24 hours, install the anchors. Mark the anchor installation point at the center of each composite panel. Drill holes at the marked points with an electric drill. The hole diameter should match the anchor size, and the drilling depth should meet the anchoring requirements. Insert the anchors into the drilled holes, ensuring that the effective anchoring depth into the concrete base is not less than 30mm and the effective anchoring depth into the solid masonry base is not less than 50mm. For masonry bases such as hollow blocks and perforated bricks, use back-tightening and knotting anchors. Tighten the anchors with a wrench after installation to ensure firm anchoring. The anchor density should be no less than 6 per square meter, arranged in a quincunx pattern.

[0012] Step 7: Apply special finishing mortar. After the composite board and anchors are installed and have passed the self-inspection of the construction unit and the acceptance of the supervisor, the finishing work can be carried out. Apply special lightweight waterproof finishing mortar. The thickness of the first coat of mortar is 3-4mm. After applying it evenly, immediately embed the alkali-resistant glass fiber mesh. The mesh should be laid flat and taut, without wrinkles or hollow areas. The overlap width of the mesh should not be less than 100mm. After the first coat of mortar has initially set, apply the second coat of mortar to completely cover the mesh. The total thickness of the mortar should be controlled at 8-10mm, and the surface should be flat and smooth. All external corners should be made into sharp corners with mesh, and should not be rounded. At the reserved hole positions, the mesh should be cut, and an overlap length of not less than 150mm should be reserved at the joint position to form a straight joint.

[0013] Step 8: Apply the inorganic colored mortar finishing layer. After the plastering mortar has dried and cured (usually 7 days), apply the inorganic colored mortar by spraying. Before application, clean the dust and debris from the plastering mortar surface and check the surface smoothness. Adjust the spray gun parameters, controlling the air pressure at 0.4-0.8 N / mm², with the spray gun outlet perpendicular to the surface to be coated, and the distance between the spray gun and the surface to be sprayed at 30-50 mm. Keep the spray gun moving at a uniform speed, spraying in a straight line for 70-80 cm, then turning 180° to spray the next row. The overlap width between the first and second rows should be controlled at 1 / 2-1 / 3 of the spray width. The application sequence is to spray the area near doors and windows first, then proceed from top to bottom, and apply to areas prone to dirt or contamination (such as window sills and baseboards) last. For areas that cannot be reached by the spray gun, use an oil brush or paintbrush. After spraying, the surface layer should have uniform patterns and consistent particles, without any exposed substrate, drips, or joint marks.

[0014] Furthermore, a surface self-cleaning treatment step can be added after step 8: after the inorganic colored mortar finish layer dries, a self-cleaning coating is scraped on, and the first coating is applied completely to ensure uniformity and no omissions; after the first coating dries (usually 24 hours), check the surface for holes, and scrape on the hole areas to reinforce them.

[0015] In this invention, the modified vitrified microsphere composite board is an A1-grade fireproof material, made entirely of inorganic materials, and features non-shrinkage and non-deformation, avoiding the risk of wall cracking and detachment later; the horizontal aluminum alloy keel bracket is made of 6063-T5 aluminum alloy, which is high in strength and corrosion-resistant, and can effectively bear the self-weight of the composite board and external loads; the special bonding mortar uses Portland cement as the base material, mixed with high molecular polymers and crack-resistant fibers, with a bonding strength of not less than 0.6MPa; the alkali-resistant glass fiber mesh has an alkali-resistant fracture strength retention rate of not less than 90%, ensuring the crack resistance of the plaster mortar layer.

[0016] Compared with the prior art, the external wall insulation adhesive anchor construction method of the present invention has the following advantages: 1. Significantly improved safety performance: The system adopts a triple fixing system of adhesive, anchor, and bracket. Special adhesive mortar achieves initial fixing, mechanical anchors form secondary anchoring, and horizontal aluminum alloy keel brackets bear the self-weight and external loads, enabling each panel and each floor to bear independent loads. This effectively avoids the risks of external wall cracking, water seepage, and detachment. As shown in the example, the system's wind load safety factor reaches more than 11.7, and its seismic performance meets the requirements of seismic intensity 8 degrees, making it suitable for high-rise building needs. 2. Excellent fire resistance and energy saving performance: The core insulation material, modified vitrified microsphere composite board, is an A1-level fireproof material, completely flame-retardant, solving the fire hazards of traditional organic insulation materials; the composite board is composed of N closed-cell crystalline particles, which have excellent insulation performance and the system heat transfer coefficient can be as low as 0.52W / (㎡·K), which improves the energy efficiency by 23% compared with the traditional system, achieving the goal of high-efficiency energy saving; 3. High construction efficiency and controllable quality: Modular composite panels (300mm*600mm) are used, and the standardized construction process reduces the amount of on-site wet work by 40% and shortens the construction cycle by more than 50%; the mortar is mixed with a fixed ratio, making it easy to control the construction quality and reducing rework costs. 4. Good durability and low maintenance cost: All materials are inorganic materials. The modified vitrified microsphere composite board does not shrink or deform. The inorganic colored mortar finishing layer has better durability and weather resistance than organic materials. The system life is the same as the building structure (≥50 years). No frequent maintenance is required in the later stage, and the maintenance cost is reduced by more than 60%. 5. Highly adaptable and environmentally friendly: Suitable for new buildings, high-rise buildings and energy-saving renovation of existing buildings, especially suitable for urban renewal projects; reduces material waste during construction, with no volatile organic compound emissions, meeting the requirements of green construction and low-carbon buildings, and helping to achieve the goals.

[0017] In summary, this invention, through optimized material selection and process innovation, constructs an external wall insulation construction system that combines safety, fire resistance, energy efficiency, and durability, demonstrating significant economic, social, and environmental benefits and promising broad market prospects. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the external wall insulation system structure according to the present invention, which describes an external wall insulation adhesive anchor construction method.

[0019] In the diagram: 1. Base wall; 2. Waterproof leveling layer; 3. Special bonding mortar + anchors; 4. Horizontal aluminum alloy keel support; 5. Modified vitrified microsphere composite board; 6. Special plastering mortar; 7. Inorganic colored mortar. Detailed Implementation

[0020] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments. Example

[0021] Construction material selection: The core insulation material is modified vitrified microsphere composite board 5, with specifications of 300mm×600mm×50mm, fire performance rating A1, and thermal conductivity of 0.072W / (㎡·K); the supporting components are 6063-T5 aluminum alloy keel support parts 4 (cross-section size 40mm×20mm, wall thickness 2.0mm); the bonding and anchoring materials are special bonding mortar (bonding strength 0.7MPa) and M6×80 back-tightening anchors; the reinforcement and finishing materials are alkali-resistant glass fiber mesh, special finishing mortar 6 (compressive strength ≥5.0MPa), and inorganic colored mortar 7 (color is beige).

[0022] Construction Process and Key Controls: This embodiment strictly follows the core process of bonding, anchoring, and supporting as described in claim 1 of this invention. The specific control requirements for each key process are as follows: Step 1: Base Treatment. The base is a C30 concrete shear wall. Before construction, the surface laitance, release agent, and dust are cleaned. A 2m straightedge is used to check the flatness of the wall surface. Three misalignments were found (maximum misalignment 12mm). After chiseling, they were repaired with 1:3 cement mortar until flat. Honeycomb and pitted areas on the wall surface are repaired with cement-based penetrating crystalline waterproofing material. After the base treatment is qualified, a 3mm thick cement-based penetrating crystalline waterproofing mortar is sprayed to form a waterproof leveling layer 2. An additional layer of waterproof mortar is applied within 300mm above and below the connection between the structural beam and the wall on each floor for reinforcement. The surface flatness deviation of the leveling layer is controlled within 3mm / 2m.

[0023] Step 2: Laying out the baseline. Using the building's ±0.000 elevation as the baseline, transfer the elevation control points from inside the electrical shaft to the construction platform of each floor's exterior wall, setting a permanent elevation control point every three floors; use a DS3 level to transfer the control points to the outer surface of the exterior wall and pop out a 500mm horizontal control line; use a J2 theodolite to pop out vertical control lines at the four corners of the building and at the elevator shaft, with a spacing of 2.5m between control lines; separate vertical lines are laid out at the corners, and the verticality deviation is calibrated to 1.2mm / 5m, meeting the design requirements.

[0024] Step 3: Installation of horizontal aluminum alloy keel brackets. Arrange brackets along the entire length of the upper and lower ring beams on each floor. Mark the installation points according to the horizontal control line, with a spacing of 500mm between adjacent brackets (less than the maximum specified value of 600mm). Use a Φ10mm electric hammer to drill holes into the base wall 1 along the bracket holes, to a depth of 60mm (10mm greater than the insertion depth of the M8 expansion bolt). After inserting the M8×50 expansion bolts, tighten them with a torque wrench, controlling the tightening torque to 15N·m, ensuring the brackets are firmly fixed to the base wall 1. After installation, use a 2m straightedge to check the flatness of the top surface of the brackets; the deviation should be ≤2mm.

[0025] Step 4: Mortar Mixing. Use a 350-type handheld electric mixer to mix the special bonding mortar and inorganic colored mortar separately. For the special bonding mortar, measure the water to dry materials at a weight ratio of 1:4.5, adding water first, then the dry materials, and mix for 5 minutes until homogeneous. Let it stand for 5 minutes, then mix again. For the inorganic colored mortar, mix the water to dry materials at a weight ratio of 1:5, extending the mixing time to 6 minutes to ensure uniform color. The consistency of the mixed mortar should be controlled between 80-100 mm. Prepare 3 sets of 70.7 mm × 70.7 mm × 70.7 mm test blocks for each batch, and test the strength after 28 days of standard curing. Use the mortar within 1.5 hours of mixing; discard any mortar left after 2 hours.

[0026] Step 5: Adhesion of Modified Vitrified Microsphere Composite Boards. Prepare a layout plan in advance, optimizing the layout to reduce non-standard boards. Use whole boards for cutting around door and window openings to avoid small-sized fragments. Use a dedicated cutting machine to cut the composite boards, ensuring a vertical deviation of ≤1mm / m. Lay the composite boards horizontally along their length, with vertical staggered joints of 1 / 2 board length (300mm) between upper and lower rows. Use vertical staggered joints at corners. Use the full-adhesion method, evenly applying a 5mm thick layer of special adhesive mortar to the back of the composite board, leaving the sides untreated. After aligning with the control lines, gently press and rub with a rubber mallet to ensure mortar fullness ≥95%, joint width controlled at 2-3mm, and surface flatness deviation ≤3mm / 2m. Reserve a full-width board opening at the scaffolding wall tie locations, 200mm × 200mm larger than the wall tie.

[0027] Step 6: Anchor Installation. After the composite panels are pasted and left to stand for 24 hours, anchoring work is carried out. Mark the installation points at the center and four corners of each composite panel (6 points per square meter, arranged in a quincunx pattern); use a Φ6mm electric drill to drill holes to a depth of 40mm in the concrete base layer, and ensure an effective anchoring depth of 35mm for the anchors (meeting the requirement of ≥30mm); after inserting the M6×80 back-tightening knot-type anchors, tighten them with a torque wrench until the anchor plate is in contact with the surface of the composite panel, and control the exposed length of the anchors to be 5-7mm to ensure a synergistic anchoring effect with the special bonding mortar.

[0028] Step 7: Application of Special Finishing Mortar. After the composite panels and anchors have been inspected and approved by the supervisor, finishing work is carried out. Two coats of special finishing mortar are applied: The first coat is 3-4mm thick. Immediately after application, alkali-resistant fiberglass mesh is embedded, laid flat and taut, with an overlap of 100mm. Additional mesh (300mm wide) is added at the inside and outside corners. After the first coat of mortar has initially set (approximately 4 hours), the second coat of mortar is applied, with a total thickness controlled at 10mm, completely covering the mesh. For outside corners, a corner trim with mesh is used to create sharp corners with a radius ≤2mm. At pre-drilled holes, the mesh is cut, leaving a 150mm overlap to create a straight joint. After finishing, the surface flatness deviation is ≤2mm / 2m.

[0029] Step 8: Inorganic Colored Mortar Finishing Layer Construction. After the plastering mortar has cured for 7 days (compressive strength reaches 3.5MPa), the finishing layer construction can begin. Before construction, clean the surface dust and moisten it with water. Use a PZ-6 sprayer to spray the inorganic colored mortar 7, adjust the air pressure to 0.6N / mm², keep the spray gun 40mm perpendicular to the wall, and move it at a speed of 0.3m / s. Use a segmented spraying method, with each segment 1.2m high and adjacent spray lines overlapping by 1 / 2 width. The construction sequence is to first spray around the door and window frames, then proceed from top to bottom, finishing easily contaminated areas such as window sills and cornices last. Use an oil brush to repair local corners, ensuring a uniform pattern. After spraying, cure for 7 days. Once the surface is dry, apply two coats of self-cleaning coating, with a coating thickness of 0.1mm.

[0030] Construction Performance Testing: The total construction period for the external insulation of this project was 21 days, which is 52% shorter than the traditional thin plastering process, fully demonstrating the advantages of the efficient construction of this invention. After the construction was completed, a third-party testing agency was commissioned to conduct performance testing: The system, consisting of the base wall 1, waterproof leveling layer 2, special bonding mortar + anchors 3, horizontal aluminum alloy keel brackets 4, modified vitrified microsphere composite board 5, special plastering mortar 6, and inorganic colored mortar 7, achieved a wind load resistance of 1.55 kPa (safety factor 11.7), meeting the seismic fortification requirements of 8 degrees and effectively solving the wind uplift resistance requirements of high-rise buildings; there was no leakage in the 24-hour water storage test (the waterproof leveling layer 2 met the standard); the thermal insulation performance test showed that the energy-saving efficiency was 23% higher than that of the traditional system, reaching the 65% energy-saving design target; the finishing layer 7 showed no cracking or discoloration after 1000 hours of artificial climate aging test.

[0031] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for constructing external wall insulation anchor brackets, characterized in that, Based on a triple fixing system of adhesive, anchor, and support, modified vitrified microsphere composite board is used as the core insulation material, combined with special adhesive mortar, mechanical anchors, and horizontal aluminum alloy keel support brackets to form a fixing structure. An inorganic colored mortar finishing layer is applied to the surface. The specific steps include: Step 1: Base treatment. Clean the surface of the base wall, repair defects such as honeycomb, pitting, and misalignment, and then apply the waterproof leveling layer. Step 2: Lay out the baseline. Based on the building facade design and insulation requirements, establish horizontal control points and vertical control lines, and lay out vertical lines at each facade corner. Step 3: Install the horizontal aluminum alloy keel brackets, align the bottom of the brackets with the horizontal baseline, and fix them to the base wall using expansion bolts; Step 4: Prepare mortar. Mix the special bonding mortar and inorganic colored mortar according to the ratio, stir evenly and let stand for later use. Step 5: Adhere the modified vitrified microsphere composite board. Use the full adhesion method to adhere the composite board to the base layer. The vertical joints of the upper and lower rows of boards should be staggered by 1 / 2 board length, and the minimum local stagger should not be less than 200mm. Step 6: Install anchors. Insert anchors into the center of each composite panel to ensure that the effective anchoring depth of the anchors meets the requirements of the base layer. Step 7: Apply special finishing mortar. Apply special finishing mortar to the surface of the composite board and embed alkali-resistant fiberglass mesh. Step 8: Apply the inorganic colored mortar finishing layer by spraying to ensure that the surface layer has uniform particles and no exposed substrate or dripping.

2. The construction method according to claim 1, characterized in that, In step 1, the waterproof leveling layer is constructed with waterproof mortar. When the base wall is a concrete or masonry structure, the surface flatness deviation is controlled within 5mm / 2m. When the base is a hollow block or perforated brick, the anchor is a back-tightening and knotting type anchor.

3. The construction method according to claim 1, characterized in that, In step 3, the horizontal aluminum alloy keel brackets are arranged along the entire length of the upper and lower ring beams of each layer. The holes of the brackets are drilled with an electric hammer, and the expansion sleeve bolts are inserted to a depth of not less than 50mm.

4. The construction method according to claim 1, characterized in that, In step 4, the water-cement ratio of the special bonding mortar is 1:4.5, the water-cement ratio of the inorganic colored mortar is 1:5, the mixing time is not less than 5 minutes, after standing for 5 minutes, it is mixed again, and the mortar is used up within 2 hours after mixing.

5. The construction method according to claim 1, characterized in that, In step 5, the modified vitrified microsphere composite board is 300mm*600mm in size and is cut using a special cutting machine. Adhesive mortar must not be applied to the side of the board. The wall ties for the scaffolding are reserved according to the whole board and are finished after dismantling.

6. The construction method according to claim 1, characterized in that, In step 6, the anchor density is no less than 6 per square meter, the effective anchoring depth of the anchor into the concrete base is no less than 30mm, and the effective anchoring depth into the solid masonry base is no less than 50mm.

7. The construction method according to claim 1, characterized in that, In step 7, the total thickness of the special plastering mortar is controlled at 8-10mm, and the corners are made with a mesh corner trim; the alkali-resistant fiberglass mesh at the reserved holes is broken, and the overlap length meets the requirements.

8. The construction method according to claim 1, characterized in that, In step 8, the air pressure during inorganic colored mortar spraying is controlled at 0.4-0.8 N / mm², the vertical distance between the spray gun and the surface to be coated is 30-50 mm, and the overlap width of adjacent spraying rows is 1 / 2-1 / 3 of the spraying width; the construction sequence is to first spray the area near doors and windows, and then carry out the overall construction from top to bottom.

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