Graphical Construction Glossary >> stairs. >> >> Cantilever Stair

Cantilever Stair
A stair that contains a series of steps that are supported at one end only.

masonry stair

A beautiful old masonry stair seen at Hampton Court Palace. It is a so called cantilever stair. It is not a true cantilever, the term floating stair would more correctly describe it.

  • Stairs like the one above do not cantilever or hang. They are often only embedded in the wall 125 or 5"
  • If the embedment was the only thing supporting them then they would soon fall.
  • They do not get any real support from the handrails.
  • The riser section of each tread bears on the back of the tread below it and so on down to the floor.
  • Stepping on a tread passes the load to the step below and so on down to the floor.
step force diagram

  • The treads when under a spot load as shown in the sketch want to twist or rotate but they cannot do this as the embedment in the wall resists it. So the load is transmitted to the next step down and so on to the floor.
  • Think about it this way, imagine matchboxes under three corners of a book. It will balance OK but it will not hold any weight on it without tipping.
  • Now imagine something gripping the short end to stop it twisting.
  • It is this resistance to the twisting force rather than the depth of embedment is what holds these stairs up.
concrete cantilever beams

These are not cantilever stairs either. The beams that are supporting them are, they are cantilevers off the central wall.

True cantilevers are few and far between because there are other ways to do it that make them appear to be supported by almost nothing. See the next page in this series.

If you didn't find exactly what you are looking for try this search tool that will search the site and the web.

"What can be added to the happiness of a man who is in health, out of debt, and has a clear conscience?
Adam Smith 1723-1790

"When we build, let us think that we build for ever."John Ruskin 1819-1900

coates hire
Hire Equipment
Furniture Fittings - Architectural Hardware - Electronic Locking Systems - Technical Hardware
BuilderBill sponsorship

BuilderBill Books

building maths
Building Maths

Stair Design
asbestos ebook
Asbestos Book

Calculator Pages.

Concrete yardage calculator

Reader's Questions.

Questions and answers.



Please Note! The information on this site is offered as a guide only!  When we are talking about areas where building regulations or safety regulations could exist,the information here could be wrong for your area.  It could be out of date!  Regulations breed faster than rabbits!
You must check your own local conditions.
Copyright © Bill Bradley 2007-2012. All rights reserved.
Page copy protected against web site content infringement by Copyscape