2.2
空心墙的特点是外层和内层之间有一个空心空间,仅通过耐腐蚀的金属拉杆连接。当水从外层渗出时,它会下降到这个空腔内,被防水板拦截,最终通过排水孔排出。为了提高防潮性能,内层空腔侧通常会进行防潮处理,兼作空气屏障。空腔还可以容纳隔热材料以降低热传递。
在施工期间保持空腔清洁对于防止可能阻碍排水的堵塞至关重…
空心砌体墙由两个叶墙组成,中间隔有空腔。外叶墙和内叶墙通过耐腐蚀的砌体拉结件连接,以确保结构稳定性。
当水渗入外墙外叶时,会进入空腔,并由安装在空腔底部的一种称为泛水的薄型不透水膜收集,随后通过泄水孔排出。
此外,在内层砌体墙的空腔侧施加防潮材料,可防止水渗入室内,同时还能起到空气阻隔的作用。
施工过程中,灰浆滴落等杂物可能堵塞排水系统,因此保持空腔畅通至关重要。使用灰浆挡板材料有助于避免空腔内排水系统堵塞。
该空腔有助于隔音,并便于在建筑内部布置用于公用设施分配的管道。
此外,在空腔中插入刚性泡沫塑料隔热板可提供保温效果。
空心墙可以是承重墙或非承重墙。在承重空心墙中,内叶墙承担结构荷载,而外叶墙为非结构性的饰面层。
在非承重墙中,内叶墙通过砌体拉结件为外叶墙提供侧向支撑。
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Q1: What are the two main components of a masonry cavity wall?
A masonry cavity wall consists of two wythes—an outer wythe and an inner wythe—separated by a hollow space. These wythes are connected using corrosion-resistant masonry ties that provide structural stability. The cavity between them serves multiple functions, including moisture management, insulation placement, and utility distribution.
Q2: How does water drainage work in a cavity wall system?
When water penetrates the outer wythe, it enters the cavity and is collected by flashing, an impervious membrane installed at the cavity's bottom. The water then drains out through weep holes. Dampproofing material applied to the cavity side of the inner wythe prevents water from reaching interior spaces and also functions as an air barrier, protecting the building from moisture damage.
Q3: Why is keeping the cavity clean during construction important?
Debris like mortar droppings can block the drainage system, preventing water from exiting through weep holes and compromising the wall's moisture protection. Using mortar deflection material or beveled bed joints helps prevent mortar from entering the cavity. Traditional practices involved placing steel ties to catch droppings, which are then removed, but modern deflection methods are more effective and easier to implement.
Q4: What are the differences between load-bearing and non-load-bearing cavity walls?
In load-bearing cavity walls, the inner wythe supports structural loads while the outer wythe functions as a nonstructural veneer. In non-load-bearing cavity walls, the inner wythe provides only lateral support to the outer wythe through masonry ties, supporting only its own weight. Both configurations use corrosion-resistant ties to maintain structural connection between the wythes.
Q5: How can cavity walls provide thermal insulation?
Rigid foam plastic insulating boards can be inserted within the cavity space to provide thermal insulation and mitigate heat transfer through the wall assembly. This placement leverages the existing hollow space without requiring additional structural modifications, making it an efficient method for improving the building's energy performance while maintaining the cavity's drainage and moisture management functions.
Q6: What additional functions does the cavity space serve beyond moisture control?
Beyond moisture management, the cavity facilitates sound insulation, reducing noise transmission through the wall. It also provides space for placing conduits and utilities for building distribution systems. The hollow space allows for flexible routing of electrical, plumbing, and mechanical systems without compromising the structural integrity of the masonry wythes.
Q7: How do masonry ties contribute to cavity wall performance?
Corrosion-resistant masonry ties connect the outer and inner wythes, providing essential structural stability and lateral support. In non-load-bearing walls, ties support the outer wythe's weight and resist lateral forces. Their corrosion resistance ensures long-term durability and prevents deterioration that could compromise the wall's structural integrity and the connection between wythes.