How to Detail a Fantastic Floating Staircase

由专筑网丁康杰，李韧编译

建造一座腾空盘旋于地面之上、平缓上升到未知高度的完美浮动楼梯极具挑战性。

建造浮动楼梯需要考虑的因素众多，例如楼梯踏面长度、踢面深度、竖板高度（两个相邻踏板表面之间的垂直距离）、扶手宽度等等。在设计这样的楼梯时，还需要权衡一些设计选项，例如楼梯是依墙壁支撑而建还是通过坚固的单纵桁承托而成？浮梯会被充满艺术张力地悬挂在一系列的吊索上，还是通过一组标准规格的钢索，将楼梯连接成一个整体？栏杆怎样才能在不降低楼梯“浮动”效果的前提下，做到既安全又符合规范?

Creating the perfect floating stair — one that appears to lightly hover above the ground and smoothly rise to unknown higher levels — is challenging.
There are countless considerations to make from tread length, to step depth, riser height and handrail width. There are also several design options to contemplate when detailing such a stair: Will it have wall supports or be a sturdy mono-stringer? Will it be dramatically suspended from a series of ceiling-hung cables, or will it feature a standard set of stringers that unite the stair as a singular object? And how can a balustrade be detailed such that it provide safety and code compliance, without diminishing the “floating” effect of the stair?


壁挂式托架浮梯踏面嵌件示意图／Diagram of floating stair tread insert with wall-inserted brackets; Image via Diamond Stairs


Fontanot玻璃栏杆浮动楼梯／Fontanot floating stair with glass balustrade

在讨论这些问题之前，注意浮梯建造的场地限制对我们来说非常重要。设计浮动楼梯，了解建筑规范细节是第一步，因为业主、开发商和其他建筑师总是最先考虑安全问题。这就像生活、爱情和建筑中的一切一样，安全第一。

所以让我们来谈一谈如何正确地建造一座符合建筑规范的楼梯，不仅使其看起来美观，而且上下都方便。

安全第一

不同国家的建筑规范存在差异，在西班牙被认定为安全的建筑可能不一定适用于加利福尼亚州。甚至在设计浮梯时，楼梯所在建筑类型不同，建筑规范也存在差异。在美国各地的一些设计案例中，地方司法管辖区制定了自己的建筑规范。

例如，芝加哥的市政法规适用于整个芝加哥市，而其他城镇则实行特别法律规范来确立其建筑建造标准。然而，大多数主要城市都通过了国际建筑规范理事会制定的国际建筑规范。这些规范基于每三年更新一次的建筑规范典章而制定。

Before getting into these questions, it’s important to pay attention to the construction restraints you’re working within. Knowing details about the building code is going to be step one in designing a floating stair, since consistent conversation surrounding their safety is always top of mind amongst homeowners, developers and other architects. Like everything else in life, love and construction, safety must come first.
So let’s talk about how to make one properly — a staircase that adheres to code, is pretty to look at and easy to walk up and down.

Safety First
Construction codes vary from country to country and what may be deemed safe in Spain is not necessarily going to be appropriate in California. Even the building typology makes a difference in designing a floating stair. In some cases across the United States, local jurisdictions have developed their own building codes.
For example, the Chicago Municipal Code applies to the entire city of Chicago, while other towns use specific laws standard to construction in their own communities. Most major cities, however, have adopted the International Building Code created by the International Code Council. These regulations are based on a model building code, which is updated every three years.



Solid Concrete Studio + Gallery 由ASWA工作室设计，其特征是通过单纵桁形成悬臂效果，并以此将楼梯踏板与一个单一的平台和金属栏杆衔接起来。这项设计位于曼谷，这种在商业空间中带有简陋栏杆的楼梯对于美国的建筑规范来说可能不太合适。

浮动楼梯的美丽之处在于，它在任何环境下都提供了开放、现代和时髦的外观。浮动楼梯看起来几乎没有重量，这取决于用于踏板的纵梁和材料。当为住宅设计浮梯时，建筑规范要宽松一些。然而，对于面向公众的楼梯，建筑师必须遵循更为严格的规范。另外，如果这是楼层间出口的主要方式，无疑必须更为谨慎地考虑建筑规范了。

根据IBC（国际建筑规范），浮动楼梯必须符合以下最低标准

• 台阶深度至少为4英寸，最高为7英寸；
• 在商业场所中，台阶深度至少为11英寸；
• 扶手的高度不应低于36英寸；
• 主轴或电缆之间的距离不应超过4英寸；
• 每级台阶必须能够承受至少300磅的集中负载。
  

Solid Concrete Studio + Gallery by ASWA features a mono-stringer cantilevered staircase with a single landing and metal railing. Set in Bangkok, this type of stair with limited railing in a commercial space may not be appropriate under American building codes.
The beauty behind a floating staircase is that it provides an open, modern and sleek look in any setting. Depending on the stringer and material used for the treads, floating stairs can look virtually weightless. When designing for residential use, construction codes are a bit more relaxed. With public-facing stairs, however, architects must follow a stricter code. If it’s the primary means of egress between floors, it also must be more carefully considered.

Per the IBC, a floating stair must comply with the following minimal measurements:

• The step rise should be a minimum of 4 inches and a maximum of 7 inches
• The step depth should be a minimum of 11 inches on commercial applications
• Handrails should not be less than 36 inches in height
• Spindles or cables should not be placed more than 4 inches apart
• Each step must be able to bear at least a 300-pound concentrated load
  

Siller Stairs设计的Floating Waves由一系列横木踏板组成，连接到波浪状的玻璃护栏和邻接的墙壁上。美国私人住宅项目的建筑规范不那么严格，这具体取决于美国各地的要求。上图所示的浮梯中，玻璃护栏足够大，台阶深度合适，为使用者提供了更多的安全保障。

设计与细节第二

一旦你彻底了解了你所选择建造浮梯的外部环境情况及标准规范，你就需要考虑一下楼梯美感问题，以及如何用合适、安全且牢固的附件来建造它。有两种常见的方法来创建浮动楼梯：悬臂离开墙壁或是上下墙面（即天花板与地板）。

加拿大制造商钻石楼梯公司（Diamond Stairs）生产了一种预制的钢质楼梯，这种楼梯的悬臂离开墙面。该公司的设计符合IBM标准，并详细说明了其通用楼梯组件如何精确地组合到一个空间中。其套件有四种尺寸，可以适应不同的楼层高度，最大踏面尺寸为42英寸。

每个套件都配有一组固定在每个踏板上的支架，以及一系列可伸缩的垂直立柱，这些立柱的高度跨越楼层间距，并连接DS系统结构。这个隐藏的后端系统保证了楼梯拥有无缝衔接的外观和坚固稳定的架构。

Floating Waves by Siller Stairs includes a series of transversing wood treads attached to wavy glass guardrail and adjacent wall. Private, residential projects in the U.S. adhere to a less-strict construction code depending on location across the country. But the ample glass featured here and appropriate step rise provide more safety for users.

Design and Detail Second
Once you’ve thoroughly researched the environment in which you’re working, it’s time think about the aesthetic of the stair and how to best create it with the right safe and strong attachments. There are two common ways to create a floating staircase: cantilevered off the wall and cantilevered off of a single or double stringer.
Diamond Stairs, a Canadian manufacturer who creates prefabricated steel staircases that cantilever off the wall, offers IBC-compliant options and details on how their universal stair kits precisely get programmed into a space. Their kits come in four sizes to accommodate various floor-to-floor heights and they offer a maximum tread size of 42 inches.
Each kit comes with a set of brackets that bolt to every tread and a series of telescoping vertical uprights that span the height of the wall and interface between the DS system and the structure. This hidden back-end system makes for a seamless look and a sturdy staircase.


Diamond Stairs公司的通用悬臂楼梯组件与支架和立柱的集成系统，创造了强大并且看起来毫不费力的浮动楼梯／Diamond Stairs’ universal cantilevered stair kit comes with an integrated system of brackets and uprights that create a strong and effortless-looking floating staircase. Diagrams via Diamond Stairs

其他楼梯定制公司，像Siller Stairs，也销售带有不同踏面材料的悬臂式离墙设计楼梯。通过Siller楼梯制造公司，客户可以定制醒目而精致的玻璃栏杆或护栏、特制木材或金属栏杆，以及踏面和天花板相衔接的立轴。

Other bespoke stair companies like Siller Stairs also sell cantilevered-off-the-wall designs with varying tread material options. With Siller, you can custom order striking yet subtle glass balustrades or guardrails, speciality wood or metal railings as well as tread-to-ceiling spindles.


Siller楼梯定制公司设计的Mistral Shine楼梯的特点是所有的玻璃踏板都直接拴在双层玻璃护栏上／Mistral Shine by Siller Stairs features all glass treads bolted to a straight glass double-guardrail

Mylen楼梯定制公司擅长单纵桁和双纵桁浮动楼梯。这种楼梯是位于商业或公共环境的多层楼梯的绝佳之选，如酒店大堂、办公室或零售空间，原因有很多，首先，镂空的楼梯允许踏板之间透光并且为楼梯下方提供额外的亮度。

其次，这些楼梯提醒人们注重建造材料。无论踏板采用的是特殊的木材或石材，还是带有粉末涂层的不锈钢，你都能够创建一套更加个性化的材料组合，并使用单纵桁和双纵桁将这些材料衔接组装。

Mylen Stairs specializes in mono-stringer and double-stringer floating staircases. These are great options for multi-level staircases situated in commercial or public environments like the lobbies of hotels, offices or retail spaces for many reasons. First, open risers allow light to filter in between the treads and provide extra brightness for spaces below.
Second, these staircases call attention to the materials used. Whether the treads feature a specialty wood or stone and the stringer is stainless steel with a powder coat finish, you have the power to create a more personalized set of material combinations with mono- and double-stringer floating staircases.


金属栏杆和主轴的单层浮动楼梯／Mono-stringer floating staircases with metal railing and spindles; Image via Eva Furniture

归根结底，浮动楼梯属于建筑中的过渡性元素。它虽具有功能，但只要设计和细节都考虑到，也可以是一抹惊艳而美观的风景。这种楼梯看起来既轻便又通风，同时能够承受标准楼梯的重量。诸如建筑规范、重量、宽度和空间长度等基本的技术细节，将帮助你挑选所需的最佳材料，或帮助你设计出可以适应任何独特环境的浮动楼梯。

At the end of the day, a floating staircase is a transitional element in architecture. It’s functional, but can also be an astounding, aesthetically-pleasing structure if designed and detailed well.
These stairs can look both light and airy and be able to withstand the weight of a standard staircase at the same time. That’s why fundamental technicalities like building code, weight, width and spatial length will help you specify the best materials needed or custom-design your floating staircase to fit any unique environment.