A few days ago, our company received a call for help from a customer. The customer reported that after the new house was renovated and dried for a period of time, mildew appeared on the wall not long after moving in, but fortunately, those mildew spots could be wiped off directly, which did not cause much impact to them. But I was worried that there would be similar problems in the future, so I called to ask.

In fact, in recent years, we have also received similar calls for help about mold growth on the walls. Although there are certain differences, the general view is that mold and mildew appear on the interior walls, especially the walls around the corners and windows. Yellowing, long hair, etc. Mildew is caused by bacteria and mildew, which manifests as black, brown and other irregular markings on the wall; long hair is caused by soluble salt and alkali in the wall after dissolving and migrating to the wall to recrystallize, which is called pan-alkali or salt. Analysis, manifested as yellowing, white powder or hair on the wall.

　　Figure 1: Real photo of roof penetration and mildew

　　Figure 2: Real shot of pan-alkali salting at the baseboard of the bathroom exterior wall

Cause Analysis:

Moisture on the wall is the main cause of mold, yellowing, and long hair on the wall. There are generally three reasons for the wall to get wet:

First, the water supply pipe or heating pipe leaks, causing the wall to be damp;

The second is that the roof or exterior wall is not waterproof or the waterproof quality is poor, and rainwater seeps into the wall or indoors;

The third is that the windows, kitchen and bathroom are not well waterproofed, which leads to the penetration of water.

solution:

First of all, the most direct way is to open more windows for ventilation and reduce indoor humidity, that is, the water vapor content. After the wall is slightly dry, use bleach or 84 disinfectant to smear the wall for moldy people; wash with 5-10% dilute oxalic acid solution for pan-alkali salting out. The two treatment solutions are easy to irritate the skin and discolor clothes, so be sure to wear rubber gloves and work clothes when operating.

If there is mildew, severe pan-alkali salting out, or there is a continuous source of moisture on the wall, the second construction of the wall should be carried out to completely cure the problem of mildew and hair on the wall. The second construction of the wall is mainly divided into three steps:

1. Remove the surface layer of the moldy and hairy wall: Thoroughly remove the loose layer of the moldy and hairy part of the wall and wait for the wall to dry.

2. Roll-brush Bluestar Corundum Interface Treatment Adhesive: After removing the moldy and long-haired loose layer of the wall, roll-brush Chengdu Putty Bluestar Corundum Interface Treatment Adhesive on the wall 2-3 times until the surface is dense and no powder falls off.

3 A full batch of Bluestar Gangyu elastic waterproof coating: Chengdu Putty Bluestar Gangyu elastic waterproof coating can penetrate into the pores and gaps of concrete to form a tough elastic waterproof film, which can effectively prevent the penetration of water while ensuring air permeability. The waterproof effect has a unique effect on the long-term maintenance of the decoration effect. After rolling the Chengdu Putty Bluestar Corundum Interface Treatment Adhesive, a full batch of Bluestar Corundum elastic waterproof coating is required on the wall, requiring at least 2-3 layers of scraping (or painting), each layer thickness of about 1mm. After one layer, you must wait for it to cure completely before doing the second layer. The final thickness after finishing construction should not be less than 2mm.

4. Putty construction: After the Bluestar steel jade elastic waterproof coating is dry, apply the last putty in strict accordance with the purchased Bluestar steel jade putty product instruction manual.