What are the key points in external wall insulation construction and quality control of construction projects?

1 Construction Conditions

The construction site should be connected to electricity and water, and the environment should be kept clean. The construction and acceptance of exterior walls, exterior doors and windows are completed. The ambient temperature of the operating location and the surface temperature of the base wall shall not be lower than 4°C, and the wind force shall not be greater than level 5. To ensure construction quality, the construction surface should be protected from direct sunlight. When necessary, sunscreen cloth should be erected on the scaffolding to cover the construction wall. The protective measures taken during the construction of the wall system can only be removed after permanent protection such as flashing and sealing paste has been completed in accordance with the design requirements.

2

Material Preparation

2.1

Preparation of adhesive glue

Put Witte Genesis adhesive and No. 425 (or 525) ordinary Portland cement are fully mixed with a mixer in a 1:1 ratio. After standing for 5 minutes, depending on the workability, add an appropriate amount of water and stir again. The following should be noted. Matters:

⑴ After opening the can, if the Genesis adhesive segregates, it should be fully stirred until it becomes slurry before adding cement;

⑵ After adding cement , stirring should not be excessive to prevent air from being stirred in and reducing the workability and other properties of the glue;

⑶ When stirring, it is advisable to use a special mixer recommended in the construction atlas;

⑷The viscosity of the glue should be controlled according to the climate conditions, and the amount of water added should be strictly controlled, and as little water as possible should be added in a slow and dripping manner;

⑸No more water should be added to the adhesive glue. Add sand, aggregate, quick-setting agent, antifreeze, polymer and other additives;

⑹ The bonding mortar should be stirred as it is used, and the stirred glue should be used within 1 hour. over.

2.2

Cutting of polystyrene boards

Standard size polystyrene boards should be used as much as possible. When using non-standard size polystyrene boards, electric heating should be used. Wire cutter performs cutting processing. Preparation of topcoat: Same as topcoat.

3

Construction technology

3.1

Base wall treatment

The base wall must be cleaned. Keep the wall surface free of pollutants such as oil, dust, dirt, release agents, weathered matter, paint, wax, waterproofing agents, moisture, frost, soil, or other materials that hinder bonding, and remove protrusions on the wall surface to make it Clean and smooth, flush the wall with water if necessary. The washed wall surface must be dried before the next construction process can be carried out. When the base material is non-concrete or clay materials such as lime sand bricks and silicate blocks, the base adhesion can be tested as follows: clean the base wall surface with neutral detergent, rinse with clean water and dry; press Prepare a small amount of adhesive glue according to the requirement of 1:1, then prepare a small piece of 75×75×50mm polystyrene board, apply the adhesive glue with a thickness of 13mm; paste the small piece of polystyrene board to the area to be inspected On the base wall, maintain for 3 days; pull the entire polystyrene board by hand. If the polystyrene board is damaged, that is, whether it is torn, broken or otherwise damaged, it is suitable for the wall; if it is bonded with glue If the first floor or base wall is damaged, it is considered not applicable to the wall.

3.2

Construction method of polystyrene board

According to the requirements of the drawing, first elastic the horizontal line of water distribution along the water distribution level of the exterior wall; it is necessary to set the system deformation joints. Then the deformation seam and deformation seam width line should pop up on the wall. The following construction methods can be used for pasting polystyrene boards:

(1) Point sticking method. Use a stainless steel trowel to apply the prepared adhesive glue around the polystyrene board with a width of 50mm and a thickness of 10mm. When using a standard size polystyrene board, 8 points should be evenly arranged in the middle of the board. The point diameter is 100mm, the thickness is 10mm, and the center distance is 200mm. When using non-standard size boards, the adhesive glue should generally be applied at no more than 6 points, but should not be less than 4 points. The ratio of the adhesive glue application area to the polystyrene board area shall not be less than 1/3.

(2) The following matters should be paid attention to when pasting the polystyrene board. The operation should be quick. Before the polystyrene board is installed in place, the bonding glue should not have any skin; the joints of the polystyrene board should be tight. and flush; only when the polystyrene board needs to be turned over and wrapped with mesh cloth, adhesive glue can be applied to the side of the polystyrene board. In other cases, adhesive glue is not allowed to be applied to the side of the polystyrene board or squeezed in. Glue (including long slats for caulking) to avoid cracking; the polystyrene boards at the corners of door and window openings should be cut out of the entire polystyrene board and must not be spliced. The action of polishing the wall should be a gentle circular motion, and should not be polished in a direction parallel to the polystyrene board. After the construction of the polystyrene board is completed, it must be left to stand for at least 24 hours before polishing to prevent the polystyrene board from moving. , weakening the bonding strength between the board and the base wall.

3.3

Laying of mesh cloth

Before applying glue, check whether the polystyrene board is dry and whether the surface is flat, and remove the Hazardous substances, impurities or surface deterioration. The following method can be used to lay standard mesh cloth: Use a stainless steel trowel to evenly apply a layer of plaster glue on the surface of the polystyrene board with an area slightly larger than a piece of mesh cloth, with a thickness of 1.6mm. Immediately press the mesh cloth into the wet plastering glue. When the glue is slightly dry and hard enough to touch, immediately apply the second layer of plastering glue with a trowel until the mesh cloth is completely covered.

At this time, the mesh cloth is approximately in the middle of the two plasters.

3.4

Processing of special parts of the system

First lay a reinforced mesh cloth according to the height requirements of different parts; then lay the standard mesh cloth continuously on it ; During construction, in order to prevent the polystyrene board from sliding down, two support blocks can be placed under each board; other precautions: Precautions for mesh cloth.

3.5

Installation of decorative parts

3.5.1

When the decorative parts protrude from the wall. After the polystyrene board is pasted, you can use the ink cartridge spring line method to mark the position of the decorative parts; apply a layer of plaster glue on both the decorative and corresponding polystyrene boards, lay standard mesh on the surface of the decorative parts, and follow the drawings. Required to be pasted onto polystyrene board.

3.5.2

When the decorative line is recessed into the wall. After the polystyrene board is pasted, use the ink cartridge elastic line method to mark the position of the decorative line; use a groover to cut grooves on the polystyrene board according to the drawing requirements. The actual thickness of the polystyrene board at the groove shall not be less than 20mm; A layer of plastering glue is scraped into the groove and within a wide range of 65mm around the groove, and then pressed into the standard mesh.

3.5.3

Precautions for installing decorative parts (wires). The standard mesh cloth laid on the decorative parts line should be thrown out more than 65mm to overlap with the standard mesh cloth on the adjacent wall; when the standard mesh cloth laid on the decorative parts (line) is cut, a new one must be added to the cut. Mesh, the minimum overlap length between old and new mesh is 65mm.

3.6

Construction of surface coating

Before applying the surface coating, you should first check whether there are trowel marks or mesh on the plaster. Whether it is completely buried. Then, repair the defects of the plaster glue or the uneven sanding areas, and polish it again with special fine sandpaper. The polishing requirements are the same as those of polystyrene board. Carefully stir the topcoat to a uniform consistency using the stirrer specified in this atlas. The surface coating is applied using the roller coating method: use a 254mm wide roller wrapped with 32-38mm wide flannel to apply a 0.25-0.5mm thick surface coating. Under general climate conditions (relative humidity of 21°C and 50°C) the drying time is 2h, otherwise the drying time should be appropriate. Do not roll dry or use excessive force during construction. The overcoat film is constructed by spraying: in order to protect the surface coating and enhance its ability to resist dust adhesion, a manual garden sprayer can be used to spray another layer of overcoat film on the surface coating. Construction should start from the top of the wall and avoid bleeding on decorative pieces or other specially shaped polystyrene boards. The following matters should be paid attention to during the construction of surface coatings and overcoats: Do not over-stir or use a mixer not specified in this atlas; during construction, the application process should continue to a natural stop, such as corners, deformation joints or decorations seams. During the painting process, the new and old painted parts must be overlapped, and an independent wall should be constructed at one time.

3.7 Repair of damaged areas

Use a sharp utility knife to cut off the superimposed layer of the damaged area to reveal a clean and regular piece that is slightly larger than the actual damaged area. On the base wall, use a disc or abrasive belt grinder to remove the surface paint along a width of approximately 75mm around the damaged area until the original plaster is exposed. Carefully remove the remaining polystyrene board and clean the original adhesive glue on the base wall. Pre-cut a piece of polystyrene board and sand the edges so that it fits snugly into the cut-out damaged area. Apply adhesive glue to the entire back of the polystyrene board, but do not apply adhesive glue to the surrounding sides. Then insert it into the damaged area and stick it to the base wall. Cover the surrounding undamaged coating with adhesive tape to prevent damage during construction. Cut a piece of standard mesh that is large enough to cover the entire patch area and overlap the original mesh by at least 65mm. Using a small, damp brush, smooth out surface irregularities and smooth edges. Use adhesive tape to cover the original non-destructive topcoat, and apply a new topcoat on the repaired area. The texture should be consistent with the surrounding area. Determine the drying time of the paint according to the weather. After it is completely dry, peel off the surrounding adhesive tape. Carefully repair the surrounding areas of the patch so that the surrounding lines are integrated.

The following matters should be paid attention to during the repair work: the polystyrene board used for repair should be exactly the same model as the original polystyrene board; when applying the repair plaster, be careful not to apply it to the Apply the original surface coating; after repairing, embed the plastering glue with a standard mesh cloth and let it sit for 24 hours. After the plastering glue is completely dry, apply the top layer of paint; after the patch paint dries, its color will be the same as that of the surrounding original paint. There is a difference in paint color, and this difference will gradually disappear.

3.8

Cleaning and maintenance of walls

3.8.1

General cleaning steps are as follows. ① Pre-wet the original wall surface with clean water; ② Prepare cleaning agent: Mix clean warm water and trisodium phosphate at a volume ratio of 16:1; ③ Apply the cleaning agent to the surface coating and brush lightly with a soft-bristle cap. If you use a hard brush or use excessive force when scrubbing, the original surface coating will be damaged; ④ Special power equipment can also be used for cleaning. At this time, the pressure of the cleaning agent at the nozzle should not exceed 4136kpa, and the temperature should not be 49°C. The nozzle should form a 40° conical water column; ⑤ Rinse thoroughly with clean water.

3.8.2

Clean mildew or moss spots.

Prepare cleaning agent: Mix clean warm water, trisodium phosphate and household detergent in a volume ratio of 16:1:3.8. The cleaning steps include ordinary cleaning.

4

Quality inspection of base walls

4.1

The base walls should meet the "Construction Engineering Quality Inspection and Assessment Standards" ( GBJ301-88) requirements for high-rise large formwork in "concrete projects" or clear water walls in "brickwork projects". The cement mortar leveling layer used to repair the wall must be firmly bonded to the wall without defects such as delamination, hollowing, and cracks.

4.2

Substrate adhesion: Apply adhesive glue to 5 representative locations on the base, with an area of ??75×75mm and a thickness of 13mm. Apply 75 ×75×50mm polystyrene board, and shall be inspected in accordance with the "Inspection Standard for Bonding Strength of Decorative Bricks in Construction Engineering" (JGJ110-97).

5

Protection of finished products

(1) Sun protection, wind and rain protection, and anti-freezing; prevent construction pollution; prevent hitting the wall when lifting items or dismantling scaffolding. (2) Prevent stepping on windows; repair damaged walls promptly.

Conclusion

Before constructing external wall insulation, it is necessary to carefully analyze the project and select the best construction method based on comprehensive consideration of the actual conditions of the project. At the same time, during construction, construction management personnel must coordinate and arrange, strictly control the construction process, and construction personnel must do quality control and acceptance of key processes to ensure the quality of the project.