Curtain wall? Window wall? What's the difference?

What is a curtain wall? What is the window wall (outer window) again? This problem seems to be self-evident, but in the actual engineering application of the building facade, many "entanglements" have indeed occurred. Due to the different understanding of "curtain wall" and "window wall" in the real estate, construction industry, design institutes and door and window curtain wall production and construction units, they have their own opinions and are entangled in project cost and quality acceptance. A certain project signed a curtain wall engineering contract, but during the acceptance and settlement, the owner unit believed that the project was not a curtain wall but an external window, and it was accepted according to the cost of the doors and windows; another project declared for curtain wall engineering awards, but on-site inspection, But it "looks like a curtain wall rather than a curtain wall", it is actually aluminum alloy doors and windows...

Mainly clarify the following issues:

    1. What is the difference between curtain wall and window wall?

    2. What are the categories of curtain walls?

    3. What are the types of windows?

1. The difference between curtain wall and window wall

1. Different ways of transferring loads to the main structure

The curtain wall transfers its own weight and load to the main structure by means of point transfer through anchored supports.

The windows are connected to the opening through the surrounding frame, and the weight and the load are transmitted to the main structure by means of line transmission.

2. The relative position is different from the main structure

The curtain wall generally protrudes beyond the outline of the main structure to form an integral facade. The window is usually inlaid within the outline of the main structure. In other words, one is on the outside of the wall and the other is embedded in the wall.

Schematic diagram of screen structure

Schematic diagram of window wall structure

2. Curtain wall category

According to the frame structure, curtain walls can be divided into 4 types: exposed frame curtain wall, hidden frame curtain wall, point curtain wall, and all-glass curtain wall.

1. Open frame curtain wall

The frame of the exposed frame curtain wall is a form of curtain wall that protrudes from the glass surface. It is divided into 3 types: horizontally bright and vertical hidden, horizontally hidden and vertical bright, and all bright. The price of the exposed frame curtain wall is about 800 yuan/㎡.

2. Hidden frame curtain wall

The hidden frame curtain wall, as the name implies, means that the frame is invisible from the facade. The frame material is on the inside of the glass and is bonded with the glass through structural glue. The price of the hidden frame curtain wall is about 1,000 yuan/㎡.

3. Point-type curtain wall

The point-type curtain wall is easier to understand. The glass and the main structure are point-connected by claws. The main structure includes steel columns, cables, trusses, etc. The price of the point-type curtain wall is the most expensive among these types, about 1600 yuan/㎡.

4. Full glass curtain wall

The all-glass curtain wall has the highest aesthetics and integrity, and the full-facade glass structure is realized by using the glass ribs as the supporting structure. Compared with exposed frames and hidden frames, the price of all glass is higher, at 1,200 yuan/㎡.

Price comparison of 4 types of curtain wall: point type>full glass>hidden frame>exposed frame. (This price is for reference only, not as a market price)

Three, the category of the window

The window wall, you can understand it as the window we often see, but the name is different. Next, let's talk about the contents of the window again.

1. Window category

a. Aluminum alloy system window

Aluminum alloy system doors and windows are high-performance windows, with better watertightness, airtightness, wind pressure resistance, etc., and the technology is more mature, and the standardization is strong. The price is 1000~1500 yuan/㎡.

b. Aluminum alloy non-system windows

Aluminum alloy non-system windows are generally combined windows, whose performance is relatively difficult to guarantee, and their appearance varies greatly depending on the material. They are commonly used in the domestic market, and the price is 500-1000 yuan/㎡.

c. Plastic steel window

The structure of the plastic steel window is PVC surface layer + steel lining. Its craftsmanship is also uneven, with good thermal insulation performance and poor appearance. It is generally considered to be relatively low-end, and the price is 700-900 yuan/㎡.

2. Opening method

The opening directions of windows are divided into 4 types: casement windows, sliding windows, flat sliding windows, and upper and lower hanging windows.

a. The overall performance of the casement window is good, the appearance effect is good, and the ventilation volume is large. However, there are certain safety hazards in meeting outside, and opening inside may affect indoor use.

b. Sliding windows are cheap and simple in construction, but the overall performance is relatively poor.

c. The ventilating area of the horizontal sliding window is large, and the facade effect is novel and does not affect the indoor space. However, the cost is more expensive, and it is not recommended to use more than 7 floors. There will be a hidden danger of falling from high altitude.

d. The upper and lower hanging windows are often used in public buildings, with low ventilation and potential falling risks.

In terms of usage, flat open> push and pull> upper suspension and lower suspension> flat push.

Four, summary

The difference between building curtain wall and window wall (outer window):

The building curtain wall is composed of a panel and a supporting structure system. It has the specified bearing capacity, deformation capacity and the ability to adapt to the displacement of the main structure, and does not share the effect of the main structure on the outer protective wall structure of the building.

Window is a general term for building parts that enclose the opening of the wall and can play the role of lighting, ventilation or observation. It usually includes a window frame and one or more window sashes and hardware accessories, sometimes with bright windows and ventilation devices.

According to this definition, no matter what kind of confusion there is between curtain walls and exterior windows, from a technical point of view, architectural curtain walls and windows have the following fundamental differences:

(1) The load transfer method is different from the main structure: the curtain wall transmits its own weight and the load and action to the main structure by means of point transfer through the anchor support; the window is transferred by the line through the surrounding frame and the opening. Transmit the self-weight and the load and action to the main structure;

(2) The way of support by the main structure is different: the curtain wall is usually hung on the main structure, and its main vertical force member is the tension and bending member (in certain cases, the seat-mounted compression-bending member is also used); the window is seated on the main body On the bottom surface of the structural window opening, the main vertical force-bearing frame member is a compression-bending member;

(3) Ability to absorb deformation is different: curtain walls generally adopt a retractable connection structure design to adapt to temperature difference deformation and interlayer deformation of the main structure; windows generally have no special structural design to adapt to temperature difference deformation and deformation of the main structure;

(4) The relative position of the main structure is different: the curtain wall generally protrudes from the outer contour of the main structure to form an integral facade; the window is usually located in the inlaid hole within the outer contour of the main structure to form a partial facade;

(5) The size of the cross section of the facade and the component profiles is different: the curtain wall is a large cross-section profile component, and a large area, continuous wall enclosure structure formed by the joint design; the window is a smaller cross-section profile component The formed wall opening has a small area and local enclosure parts.

The curtain wall is a frame structure with a large supporting span. In addition to the ferrule connection between the columns themselves, the movable joints between the beams and the columns, and the elastic inlaid joints between the glass and the frame, the curtain wall and the building's peripheral closing are also elastically sealed Glue seal.

There is no special movable joint design between the window frame members with a small span, and the assembly joint gap between the frame members absorbs a certain amount of deformation of the window itself. Wet cement mortar is often used for filling between the window frame and the main structure. The installation gap cannot adapt to the relative displacement between the window and the wall of the opening after curing.

Regarding curtain walls and doors and windows, in terms of engineering cost, generally speaking, the cost of curtain walls is higher than that of windows. Of course, some high-performance and high-quality door and window systems are more expensive than ordinary curtain walls, and curtain wall materials are used. The cost of large doors and windows cannot be equal to the cost of ordinary aluminum alloy doors and windows.

Building curtain walls and external windows are important building components related to human use and social public safety. All parties involved in the construction of the project should correctly understand the difference between curtain walls and doors and windows from a technical and economic point of view to ensure reasonable project costs. The correct selection of materials, design and production, and installation and construction can ensure the quality, performance and safety of the building curtain wall project.

my country's architectural curtain walls were introduced from abroad after the reform and opening up in the 1980s, and developed from transparent aluminum alloy glass curtain walls to non-transparent metal, stone and man-made panels. The aluminum alloy glass curtain wall developed on the basis of aluminum alloy doors and windows is the most mature and common application, accounting for about 3/4 of the building curtain wall. The "no distinction between windows and walls" between curtain walls and doors and windows mentioned in this article is mainly the confusion between aluminum alloy glass curtain walls and aluminum alloy exterior windows.

Finally, we use another picture,

Summarize how to distinguish the key content of "windows and walls":

After more than 30 years of rapid development, my country has become the world's largest country in the production and use of aluminum alloy doors and windows and building curtain walls. What is a curtain wall and what is an exterior window is determined from a technical point of view, not just from the appearance. The enclosure structure made of curtain wall profiles and window profiles is not a curtain wall as long as it does not meet the structural requirements of the curtain wall. The former is a "curtain wall material window", and the latter is a "window material false curtain wall". A correct understanding of the difference between curtain wall and window from a technical and economic point of view is useful for solving the problems of materials, structure and cost in curtain wall door and window projects for many years, resulting in "no separation of windows and walls", which affects the acceptance and settlement of curtain walls. And the problem of engineering quality and safety is indeed necessary and practical.

This article is reproduced from: China Curtain Wall Network