Open aluminum panel curtain wall: every hole on the waterproof board is a hidden danger

Views:69 Author:Site Editor Publish Time:2026-10-07 15:41:10 Orgin:Site

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[Introduction] Record a real engineering site note, this pit has repeatedly played out in open curtain wall projects, and it is worth being warned in advance by various professions.

Open aluminum curtain walls often leak water not from the outer panels, but from the metal waterproof backboards inside various pipeline crossings. The opening of the cave is disorderly, the sealing is disorderly, and the professional interface is blurry, which can easily lead to water leakage and tearing in the later stage. This article outlines the key points for practical control in design and construction.

Everyone who works on curtain walls knows one thing: open aluminum panel curtain walls, waterproofing is not on the panels at all, it relies entirely on the inner waterproof backplate (galvanized steel plate, aluminum plate, etc.)

The panel is sewn and not glued. When the rain falls, water directly enters the cavity, relying on the galvanized steel plate inside to guide the water out and block it outside.

But the easiest place to overturn on site is precisely here - the pipeline passes through the waterproof layer.

Lighting, access control, monitoring, weak current All kinds of pipelines have to pass through. The location was opened haphazardly, the hole was blocked haphazardly, and the responsibility was unclear. In the end, the water leaked, and you blamed me, I blamed you, and the arguments could be dragged on until after the completion and delivery.

Today's article is a real engineering note.

What exactly happened on site?

An open aluminum panel curtain wall project, with no glue applied to the exterior seams and a waterproof system relying entirely on galvanized steel plates on the inside. The detailed structure is shown in the following figure

Typical nodes of slotted aluminum panel curtain wall

As a result, during the construction phase, problems erupted in a concentrated manner:

·Lighting pipelines need to be threaded

·Access control pipelines need to be threaded

·Monitoring and weak electricity should also be worn

The on-site situation is as follows:

Some install waterproof boards first and then drill holes, while others lay pipes first and then install waterproof boards. The sizes of the openings vary, the sealing is arbitrary, and the glue is applied carelessly.

At the coordination meeting, all parties directly argued:

·Should we lay the pipeline first or install the waterproof board first?

·Who will open the hole? Is the pipeline unit positioned and the curtain wall open? Or should the pipeline unit open it themselves?

·Who will block the hole? 

·Once there is a leak, who is responsible?

To put it simply, responsibility is not predetermined, the process is not fixed, and in the end, there are all hidden dangers.

1、 Design phase: Don't leave the problem to the site

Many water leakage pits are not due to poor craftsmanship of the workers, but rather due to failure to comply with the design drawings during the design phase.

1）Comprehensive professional mapping is required

Architecture, curtain wall, electrical, lighting, and weak current - all professional drawings are checked together. Any location that requires the use of waterproof steel plates should be marked in advance, and the waterproof method should be confirmed with the curtain wall design and obtained in writing.

2）Don't wear if you can, and wear less if you can

The fewer holes on the waterproof board, the safer it is. If you really can't avoid it, prioritize choosing a location that is relatively less prone to water ingress - such as under the eaves, behind vertical lines, or in low areas.

3）Can embed casing and never drill holes on site

A metal sleeve with a waterstop wing ring can be directly embedded on the waterproof board for precise positioning. The pipeline runs through the casing and is sealed at both ends, which is ten times more reliable than on-site drilling and gluing.

One precise drawing during the design phase is better than ten glue repairs during the construction phase.

2、 Construction phase: Responsibility must be clearly stated, otherwise it will lead to disputes

The four things that are easiest to argue on site are: who opened the hole? Who blocked it? How to block it? Whose fault is it if it's missed?

1）Hole opening responsibility

·The point can be accurately confirmed in advance: the curtain wall unit reserves standardized openings in the factory.

·It is necessary to locate on site: who has the pipeline and who has the hole. It is strictly prohibited to cut, expand or damage steel plates indiscriminately.

2.）Blocking responsibility - an iron law

Whoever wears the pipe is responsible for blocking it. Whoever takes away their child.

Don't expect me to open a hole and you to help block it. As soon as they help, the responsibility gets mixed up, and as soon as there is a leak, they blame each other. After the sealing is completed, the curtain wall unit must review and accept it.

3） Requirements for sealing construction (cannot be confused)

·It must be operated by trained professionals, not by casual workers applying glue.

·It is recommended to use weather resistant sealant with a design service life of not less than 25 years. The sealant should undergo compatibility testing with the contact material, and the use of ordinary sealant is prohibited.

·Double seal the opening of the curtain wall: add a water coating on the outer side, wrap the surrounding area with weather resistant glue to form a second waterproof insurance. At the same time, do not block the original drainage path of the curtain wall cavity to avoid the inability to discharge water from the cavity volume.

·100% concealed acceptance, taking photos for record keeping, and signing a closed loop.

4）Include responsibility in the agreement

Make sure to clearly state all aspects of opening, sealing, acceptance, and responsibility in black and white. Otherwise, if there is water leakage after delivery, the property management, party A, construction unit, and weak current unit can be involved for several years.

There is another reality that needs to be reminded: rainwater will flow around the metal back panel after entering the curtain wall cavity. The leakage marks seen indoors are often not the actual location of the water inlet hole. This further increases the difficulty of later investigation, and after a leak occurs, it is easier for all parties to shift responsibility to each other.

How to check after a water leak?

Since water will splash around in the cavity, the investigation cannot only focus on the dripping points indoors. The correct sequence is: first check all the pipe penetration points and joint points on the exterior facade, and then check if the cavity drain hole is unobstructed. You can use a water spray test to confirm section by section. First find the source, then determine the responsibility, don't throw the pot at each other as soon as you come up.

In addition, we should also be vigilant about the addition of new pipelines after the completion of the renovation. Many projects have good control during the construction period, but after delivery, new floodlights and monitoring equipment are added, and holes are directly drilled on the existing waterproof backboards on site without design review or sealing according to specifications, which can also create long-term water leakage hazards.

3、 A sincere statement

The life of an open aluminum panel curtain wall is the waterproof layer on the inside.

Every hole on the waterproof layer is a risk point for water leakage.

·The design is not in line with the blueprint, with one hole randomly opened

·Construction without clear responsibility, one hole blocked haphazardly

·Check without leaving any traces. If there is a leak, shake the pot

Many projects have beautifully designed facades and end up being planted on these small through wall openings.

Remember three sentences:

If possible, do not open a hole;

It is necessary to open a hole and embed it in advance;

Whoever wears it will block it, and the responsibility should be clearly stated.

Don't wait until there is a leak to remedy it. No matter how much repairs were made back then, it was difficult to completely eliminate the hidden dangers.

It's best to fill this pit during the design phase.