Many construction masters and owners often step on pits: the waterproof is put into water and closed after a day or two of brushing, resulting in foaming, softening, delamination of the coating, and repeated water leakage in the later stage. The water closure test does not depend on the dryness of the watch, but on the dryness of the watch.
The coating film is fully cured and dry
。

First, after the waterproof paint is finished, how long can the water be closed?

✅ K11 / JS 聚合物水泥防水（家装卫生间、厨房最常用） 常温 20℃通风良好：全部涂刷完成后 48h（2 天）以后再闭水； 低温＜15℃、阴雨天、通风差：延长到 72h（3 天）

✅ 单 / 双组分聚氨酯防水涂料（屋面、外露防水） 常温建议 72h（3 天）固化后 闭水；反应型聚氨酯成膜慢，提前泡水极易破坏涂膜结构

⚠️ 判断标准（比时间更重要）： 手摸表面不粘手、指压不留印，才算实干；仅仅表面不粘灰（表干）绝对不能蓄水。 ⚠️ 水池、鱼池长期浸水场景：建议养护 7 天以上再满水测试，提升长期耐水性抖音百科

How long does the closed water test need to be closed?

According to domestic standards JGJ298, JGJ/T299:
Minimum ≥24 hours
This is the bottom line of acceptance. The Communist Party of China...

• Routine acceptance of home improvement toilets:
  24h
  Supervision/Property General Standards
  

• Engineering, roofing, high-standard construction sites, foreign trade project recommendations:
  48h
  It is easier to detect hidden dangers of slow seepage
  

• Water storage height:
  20~30mm（2–3cm）
  Do not go too deep to prevent the roof load from exceeding the standard; do a good job of marking the water level.
  

3. Key points of closed water operation (it is very practical to send sales to customers)

1. Plug the floor drain, pipe root, and make water barrier at the door; drain water slowly, and pad something at the bottom to buffer to avoid washing out the coating film
   

2. Key inspections: drop in water level, yin and yang corners of pipe roots, and whether there are water stains on the roof downstairs
   

3. Leakage treatment: put water to dry, repair the damaged position, wait for solidification after the repair is completed, and then redo the closed water.
   

4. After the closed water is qualified for drainage, make a cement mortar protective layer as soon as possible to avoid tiling and construction scratching the waterproof layer
   

IV. Common misunderstandings

❌ Mistake 1: After brushing for 24 hours, the inside of the closed water coating film has not been completely hydrated and formed. Soaking in water will interrupt curing, and the waterproofing will fail directly. ❌ Mistake 2: If the closed water does not leak for a few hours, even if the qualified slow seepage cannot be seen in a short time, the minimum requirement of the specification is 24h. ❌ Mistake 3: The roof is exposed to waterproofing and directly stores water for a long time. The exposed weatherproof model can store water for acceptance, but the roof water storage time cannot be too long, timely drainage to prevent long-term soaking in water + sun exposure to accelerate aging.