Causes and Prevention Methods of Silicone Pollution on Building Curtain Wall

13 / 01 / 2022

Causes and Prevention Methods of  Silicone Pollution on Building Curtain Wall
As the outer structure of the building, the building curtain wall mainly plays the functions of heat insulation, sound insulation and waterproofing. In addition, the decoration of the curtain wall is also an important factor for its wide application.
However, many curtain buildings wall become dirty due to surface silicone pollution soon after built, which not only breaks the hearts of architects, but also greatly increases the maintenance cost of building curtain walls.

What caused curtain wall silicone pollution?

The main manifestation of the pollution problem is that the pollution area spreads around along the seam of the silicone sealant.
According to the different forms of pollution, curtain wall silicone pollution can be divided into two types: Penetration (seep) pollution and vertical flow pollution.
  • Penetration pollution

Penetration pollution is common in the curtain wall of porous materials such as stone. The main phenomenon is that the surface of the substrate in contact with the silicone joint has blackening and discoloration caused by similar oil infiltration.
Penetration contamination is an irreversible process, once it occurs, it cannot be eliminated, and the entire panel can only be replaced.

The source of osmotic contamination is the small molecule alkane plasticizer (commonly known as "white oil") in the silicone sealant.
The white oil will gradually migrate to the surface of the construction silicone sealant over time, and then enter the interior of the stone along the small pores of the stone, resulting in unremovable pollution.

Therefore, when using other porous materials such as ceramic board and cement fiber board, attention should also be paid to the problem of silicone sealant contamination.
  • Vertical flow pollution

Vertical flow silicone pollution occurs on almost all types of curtain walls. The main phenomenon is that there are "flow marks" of varying degrees on the curtain wall panels. The longer the time, the more serious the pollution of the curtain wall.

The main reason for vertical flow pollution is that the surface of the silicone sealant carries electric charge, which is easy to absorb dust in the air. When encountering rainy weather, the dust is washed by rainwater on the curtain wall, forming vertical flow pollution. the pollutants will accumulate more and more as times go on if no action is taken, seriously affecting the appearance of the curtain wall.

Although vertical flow silicone pollution can be removed, it requires a lot of manpower and material resources, especially on high-rise curtain walls, which is difficult and expensive to clean.

Preventive measures for curtain wall silicon pollution problems

For seep pollution, it can be completely eliminated.
First of all, it is necessary to choose high-quality special silicone sealant for stone(silicone for granite), which does not contain volatile pollutants such as "white oil"; antas-195 natural stone silicone sealant is  designed for weather resistant joint sealing in stone cladding and stone constructions without sealant pollution.
Secondly, before construction, building silicone sealant and the bonded substrate should be sent to a professional testing organization or sealant manufacturer to make stone sealant contamination test, avoid risks in advance. Jointas is top 3 silicone sealants manufacturer in China which has 3 production bases, all silicone sealants are strictly tested before delivery.

For vertical flow pollution, prevention should be mainly taken from the curtain wall design, such as designing reasonable drainage measures or rain-blocking measures to prevent dust from flowing directly to the curtain wall along the rainwater to form a pollution zone, thereby reducing the frequency of curtain wall cleaning.
Jointas, Lead A Green Life!