High moisture content in the base layer during the application of fireproof coatings can lead to various issues. When the top coat is applied using high-grade or solvent-based paints with a high emulsion content, the resulting coating film becomes too dense, preventing proper moisture release. This often leads to blistering, peeling, or loss of adhesion between the coating and the base layer.
Additionally, if the bottom layer uses a water-based fireproof coating while the top layer applies a solvent-based one, especially under direct sunlight and high temperatures, it can cause uneven drying and internal pressure buildup. Poor-quality, non-water-resistant putty used as a base can also allow moisture to penetrate, weakening the bond between the coating and the surface. In tunnel construction, if the interval between layers is too short and moisture or solvents haven't fully evaporated, this can result in long-term damage. Furthermore, if the fireproof coating is exposed to rain or dew after application, it may not dry properly, leading to further problems.
To prevent these issues, it's crucial to ensure that the moisture content of the base layer does not exceed 8% before applying any solvent-based fireproof coating. The underlying coating must be completely dry before applying the next layer. Painting should be done away from direct sunlight, and high-quality, fire-resistant putty should be used for exterior walls. It’s also important to wait until the previous layer is fully dry before applying the next coat. Avoid painting in rainy weather or when humidity levels are high, as this can interfere with the drying process and compromise the coating’s performance.
If blistering occurs, the affected area should be removed, the edges smoothed, and the primer and topcoat reapplied. In cases of widespread blistering, all damaged sections should be stripped, the wall repaired, and then the fireproof coating reapplied.
This article is from Wuhan Xinghai Fire-fighting Materials Co., Ltd. http:// Please indicate the source.
Http://news.chinawj.com.cn Submission.
Shandong Yahong New Materials Technology Co., Ltd , https://www.okrooftile.com