Common problems and preventive measures of external wall insulation construction

At present, with the popularity of external wall insulation system in the domestic market, various forms of engineering quality problems gradually appear. In the construction process of the thermal insulation system, there will be quality risks caused by the weather conditions at the construction site, the operation level of the construction personnel, construction technology and other problems. The problems that often occur are mainly reflected in the following aspects: poor appearance quality caused by the uneven surface, water leakage caused by the failure to handle the detail nodes, falling off of the external wall bricks caused by the poor pasting, and wall cracks caused by the nonstandard practices And so on.

1. Poor appearance quality caused by uneven surface

The causes and preventive measures for the surface irregularity and poor appearance quality of the external wall are as follows:

1.1 storage and safekeeping of materials

There are many kinds of materials for the external wall insulation system, and each material must be applied according to the requirements. In many construction sites, the most common insulation board is stacked in the open air. It is easy to cause structural deformation and shrinkage deformation of the board due to the sun and rain, which affects the flatness of the wall. Especially in the summer when the temperature is high, the EPS board is easy to be deformed and the wall surface is not smooth when exposed and exposed for a long time. Preventive measures: according to the characteristics of external insulation construction, make a flow construction plan in advance, organize the construction personnel, and ensure that the subsequent processes are inserted in time.

1.2 impact of inadequate base treatment

In the construction process, the base is often not treated or the treatment is not in place, especially the unevenness of the concrete wall after formwork running, which is generally not willing to be treated in the actual construction process, resulting in the different thickness of EPS board adhesive, and the recent deformation in the later stage, resulting in the uneven wall surface. Preventive measures: the base must be well treated and inspected to ensure that the base is flat, solid and clean.

1.3 influence of anchor bolt in construction

In many external thermal insulation walls, we often see a clear round mark, which is the appearance quality defect caused by improper construction of anchor bolt. Preventive measures: select the appropriate length of anchor bolt according to the thickness of external insulation, and ensure that the anchor bolt cap can be slightly lower than the insulation board by about 2mm during the anchor bolt construction.

1.4 impact of low construction level of professional team

At present, the quality of the construction team is uneven, the construction level of the construction team with low quality is poor, the construction quality is difficult to guarantee, resulting in poor surface smoothness and other quality problems. Preventive measures: strengthen management, and select professional teams with perfect construction quality management system, social reputation and good service quality through visiting and investigating the projects under construction and completed and delivered for use by professional teams, and conducting strict review on their construction qualification and training of workers on duty.

2. Cause and preventive measures for leakage and water leakage of detail joints

In general, the actual situation of the insulation parts on site is complex, which is difficult to be described in detail in the design drawings. The professional team must draw the detail drawing of the insulation nodes of different parts on site, and report to the relevant units for approval before construction. The causes and preventive measures of water leakage are as follows:

(1) The construction of dividing strips does not follow the requirements of slotting and inlaying, resulting in seepage and water leakage. In order to overcome the continuous area of insulation wall is too large, and it is easy to crack under the influence of high and low temperature. Preventive measures: try to reduce the setting of dividing strips. During the construction of dividing strips, use a special slotter to cut the insulation board into notches. Never cut through the EPS board, and then inlay it.

(2) The external insulation forms a "facing to the sky joint" on the parapet top or windowsill closing, which causes leakage and water leakage. In the design, no special consideration is generally given to the closing of the external insulation at the parapet top or windowsill, only relying on the anti wrapping of the insulation construction to strengthen. However, in actual construction and use, the above parts are often damaged by trampling, resulting in seepage and water leakage. Preventive measures: it is recommended to make concrete or use thermal insulation mortar to press the top at the external thermal insulation closing of the above parts, and then strengthen the grid cloth reverse wrapping and anti crack mortar plastering.

(3) The installation and closing of the external wall windows are not standardized, resulting in water leakage. There are two methods for the installation of exterior wall windows, one is to plug the opening first and the other is to plug the opening later. In the exterior wall with external insulation construction, because the closing is not solid or the fixed window frame is perforated, it is easy to cause leakage and water leakage. Preventive measures: in order to ensure the closing quality of the exterior wall window opening and reduce the leakage point, the back plug construction can be used to strengthen the inspection and control of the construction quality of the opening. During the installation of exterior wall window, it shall be avoided to drill and fix directly on the frame body at the lower opening of window frame.

(4) After the construction, rainwater pipes, louvers, fixed components, etc. attached to the wall will cause leakage and water leakage. Preventive measures: it should be done in advance before the construction of external insulation.

3. The external wall brick falls off due to poor adhesion

(1) The hollowing of the leveling mortar and the main wall, especially the water seepage for a long time, is easy to occur the continuous hollowing expansion, making the insulation layer associated with hollowing or local damage. Preventive measures: before the construction of the insulation layer, check the quality of the leveling layer and deal with the hollowing in time.

(2) The unqualified plastering mortar results in large area falling off of the outer wall surface, the bonding mortar is not re inspected in the site, and the unqualified raw materials are used with poor adhesion. Preventive measures: strengthen the quality control of raw materials entering the site, do a good job in compound inspection of materials entering the site, and make a good sample in advance.

(3) Insufficient amount of adhesive causes large area of falling off of outer wall. Preventive measures: conduct training for on-site quality inspection personnel, which requires that on the basis of understanding the structure of the insulation layer, the on-site testing methods should be clear. Under the premise of ensuring the quality of the adhesive, control the bonding area: multi-layer building paint wall with 7 floors or less