Is it difficult to waterproof prefabricated buildings? Check to see if the sealant is used correctly

Since the components are assembled on site, a large number of assembly joints will be left, and these joints can easily become channels for water penetration. Therefore, we must attach great importance to the processing of waterproof joints of prefabricated exterior walls.

The so-called prefabricated building means that the structure of the building, such as wall panels, columns, beams, floors, stairs, etc., are disassembled according to certain specifications, prefabricated in the factory, and then transported to the site for assembly. Since the components are assembled on site, a large number of assembly joints will be left, and these joints can easily become channels for water penetration. Therefore, we must attach great importance to the processing of waterproof joints of prefabricated exterior walls.

As one of the main waterproof materials used, sealant plays a key role in the sealing and waterproofing of prefabricated buildings. If there is a problem, it will cause water leakage, air leakage and other problems, thus affecting the overall quality and use experience of the building. In this issue, the editor will introduce to you the common problems in the application of sealants in prefabricated buildings.

Poor adhesion

1.It may be that the sealant was not tested for adhesion before use, or the sealant was applied directly without cleaning the dust, oil, sand and other substances on the surface of the base material. These will cause damage to the relationship between the sealant and the base material. affect the bonding effect between them. Therefore, during the actual glue construction process, it is necessary to pre-treat the surface of the base material to be adhered, clean the dust, oil, sand, loose layers that are easy to fall off, etc. on the surface of the base material, and perform adhesion tests on the base material used in the project in advance. Test to achieve the ideal bonding effect between the base material and the sealant.

2.An inappropriate sealant was used and there was no good adhesion between the sealant and the cement substrate as shown. Even if the construction is carried out according to the process and cured normally, it will still fall off as soon as it is pulled off, and it will not play the role of sealing and waterproofing. Due to the constant emergence of new building materials and the application of new surface treatment technologies, it is difficult to guarantee that sealants are suitable for all materials. In some cases, a primer liquid can be used, which can also effectively improve the adhesion between the sealant and the adhered substrate. Bonding properties, thereby achieving better bonding results.

Poor appearance

Under normal circumstances, the sealant produced will appear as a uniform and fine paste without obvious particles or crusting. If there are crusts or obvious particles on the surface of the sealant that affect the "appearance" of the sealant surface, it may be due to the following two situations:

1. Before sealing and caulking, we will cut the glue nozzle to the appropriate size according to the size of the gap and the needs. The glue can be applied directly without trimming or subsequent trimming. If you find that there are crusts or particles in the glue during the gluing process, you need to check whether it is caused by the glue nozzle and seams, such as whether there is crusting or semi-cured colloid at the glue nozzle, and whether there is dust at the seams. Particles.

2. Paste masking paper on both sides of the glue application. Use a scraper or a small scraper to trim the glue. If there are still rubber or particles found after trimming, it may be that the trimming time is too long and the trimming is repeated many times, resulting in rubber on the adhesive surface. Or the trimming tools are not clean, or the environment is affected by dust and sand.

If you suspect there is a problem with the quality of the sealant, you can apply glue and scrape it flat on the surface of the clean substrate to confirm whether there is a problem with the quality of the sealant.

Bubble problem

After the sealant is applied and cured, there are raised bubbles on the surface, and the interior is hollow after being cut.

If the number of bubbles on the glue surface is small and single, and the interior is smooth after being cut, it can be judged that air was trapped during gluing. Pay attention to whether the glue amount is full and the gluing speed is uniform during gluing;

If there are many bubbles on the glue surface and are densely distributed, and there are large bubbles after curing and cutting, it can be considered that the glue is applied when the base material is wet or a chemical reaction occurs due to incompatibility between the sealant and the base material. Construction should be carried out when the surface of the base material is dry. At the same time, pay attention to whether the sealant is compatible with the base material. Do a compatibility test in advance and select a suitable sealant to match the base material.

MS polymer sealants, Silicone sealants, Acrylic sealants, Polyurethane sealants