| Spiral Stairs are staircases that are constructed | | | | used as main stairs within a dwelling. The clear |
| solely of tapered treads wrapping around a central | | | | tread width of a secondary spiral should be |
| column. As they twist round in a tight curve they | | | | 600mm which (depending on the specific model / |
| offer a very space-saving solution when accessing | | | | design) gives a 1450mm diameter when taking |
| a different floor, taking up considerably less floor | | | | into consideration the centre column and the |
| space than a conventional staircase. | | | | balustrade to both sides. The height of each step |
| In medieval times, spiral staircases were | | | | should not exceed 220mm and the centre going |
| commonly located in circular castle turrets and | | | | should be at least 145mm. A spiral used as a main |
| were often constructed in stone. They were | | | | staircase should have a clear tread width of |
| configured in a clockwise assent to give attacking | | | | 800mm (1800mm diameter) and 220mm |
| right handed swordsmen a disadvantage whilst | | | | maximum rise and a 190mm minimum central |
| ascending. These days spiral staircase designs | | | | going. Generally the opening in the floor for a spiral |
| have developed dramatically and whilst maintaining | | | | should be around 100mm larger than the diameter |
| their space saving benefits, are manufactured in a | | | | whether the opening is square / rectangular or |
| variety of materials such as glass and stainless | | | | circular. For example a 1600mm diameter spiral |
| steel. They now offer the right property a | | | | should have a 1700mm square or diameter |
| stunning alternative to a standard staircase, | | | | opening. This is to allow for a 50mm 'knuckle gap' |
| becoming a stylish 'feature' of a room. Due to | | | | between the handrail and edge of floor / wall on |
| their tight construction they are not overly easy | | | | both sides. The top step of a spiral staircase is |
| for the elderly or disabled to use and moving large | | | | normally an enlarged step which connects the |
| pieces of furniture between floors can prove | | | | centre column to the edge of the floor. This top |
| tricky. For safety reasons there are currently | | | | landing platform can sometimes be shaped to |
| various rules and regulations governing the size of | | | | allow for slightly smaller openings. |
| spirals staircases installed in new builds and | | | | Commercial Spiral Staircases |
| renovations in residential and commercial settings. | | | | Categories C-E of BS5395 covers the required |
| UK Building Regulations | | | | dimensions for commercial staircases - those to |
| Spiral staircases have their own 'British Standard' | | | | be used by the public. The guidance ensures that |
| dedicated to them - BS 5395 part 2. The BS is | | | | people unfamiliar with the spiral can use it safely. |
| referred to in Building Regulations part K and | | | | With all commercial spirals staircases there is a |
| ensures the spiral staircase is large enough for the | | | | requirement of a centre column handrail and a |
| given application. Within the document, spirals are | | | | 'rest' platform if the flight consists of more than |
| divided into five categories, A-E with A being a | | | | 16 risers. Category C is for a small semi-public |
| secondary domestic spiral and E being a large fully | | | | stair and has to have a rise height of no more |
| public spiral. Each category dictates the relationship | | | | than 220mm and a clear tread width of 800mm. |
| between the rise (height of each step) and going | | | | The diameter of this (with the centre column |
| (depth of each step) and 'clear tread width' (the | | | | handrail in place) is therefore around |
| distance from the inside of the handrail to the | | | | 1900-2000mm. Category D is for a semi public |
| centre column) required for the spirals' usage. | | | | stair serving more than 50 people. The regulation |
| Generally, the more people the spiral is providing | | | | looks for a minimum rises of 190mm and a clear |
| access to, the larger diameter and the smaller the | | | | tread with of 900mm (2100mm diameter). |
| rise height, making it safer and more comfortable | | | | Category E deals with spirals intended to be used |
| to climb. | | | | by large number of people at one time - shopping |
| Domestic Spiral Staircases | | | | centre or football stadium for instance. A |
| With domestic spirals there are two generally | | | | 1000mm clear tread width is required along with a |
| rules to adhere with - there should be no gap | | | | 190mm maximum rise and 250mm minimum |
| between the treads or the balustrade of more | | | | going measurement. |
| than 100mm, and the balustrade should not be | | | | The guidelines covered by BS5395 are subject to |
| constructed with climbable rails. Category A and B | | | | interpretation by planning offices and are not |
| of BS 5395 deal with the measurement | | | | always set in stone. A relaxant is sometimes |
| requirements for domestic spiral staircases. | | | | offered when, for example, one is replacing an |
| Category A is referred to as a secondary | | | | existing spiral. |
| domestic spiral and category B covers spirals | | | | |