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This article is a guide to Spiral Staircases and UK Building Regulations, it covers the basic requirements you need to check in order to meet UK Building Regulations K1 and the associated British Standard BS5395-2 1984. You can get more information by checking out our website

So – Why do I need to know this boring stuff about Rules and Regulations?

Two questions I get asked regularly are:

Q. Surely if I buy a spiral staircase from a Manufacturer, or auction website, it will automatically meet UK Building regulations?

A. Actually it may surprise you to know that there is no legal requirement for a manufacturer or supplier to meet UK building regulations in order to sell you a spiral staircase in the UK. ALWAYS ASK YOUR SUPPLIER – does this spiral staircase meet building regulations for my specific type of project? Why? Because a high number of imported spiral staircase kits that are made to European standards do not meet UK regulations! Reputable suppliers will always have Building Regulations information on their websites so you can make an informed choice.

Q. What do I need to be aware of if I want to meet Building Regulations, do I even need to comply?

A. In my article below I cover some of the most important points to be aware of when buying and installing a spiral staircase. If you still aren’t sure, then simply ask your supplier to state in writing that the staircase you want to buy does meet UK building regulations.

What are the Regulations and Standards for a Spiral Staircase?

Approved Document K1 – Section 1.21 deals with Spiral and Helical stairs

K1 Building regulations is the approved document which covers Stairs, Ladders and Ramps. In K1 section 1.21 Spiral and Helical stairs, the regulations refer you to a British Standard – BS5395-2:1984. If your spiral staircase complies with BS5395 then it also complies with K1 building regs.

There are exceptions to rules, it can depend on your circumstances whether building control will waver from these standards.

So what is BS5395 and why is it important?

BS5395-2:1984 is a Code of Practice which covers the dimensions and general construction of spiral and helical stairs. A Code of Practice is an advisory document, a set of standards which in the opinion of BSI gives you “best practice” advice regarding spiral and helical staircase construction. It is not a “Specification Standard” so the requirements in BS5395 are not mandatory. However, compliance with BS5395 is required under K1 building regulations, so the message is clear – if you want to be certain your spiral staircase complies with the regs, it needs to meet BS5395-2:1984. Of course, it is possible your Building Control Surveyor will allow a non-compliant staircase under certain circumstances, read on for more info!

Secondary domestic spiral staircase should have:

  • 600mm clear tread width, measured from the outside of the centre post to the inside of the handrail
  • Centre goings of 145mm minimum – measured from the nosing of one tread to the nosing of the next tread
  • No gaps greater than 99mm in the balustrade
  • No gaps greater than 99mm between the treads – (open tread stairs usually need to have Child Safety Riser bars fitted)
  • Maximum riser height of 220mm (the height from the top of one tread to the top of the next is called the riser height)
  • e.g. For accessing a single habitable room in a loft conversion, Garage conversion, extension etc

Typical examples would be our Gamia 1400mm diameter spiral staircase. This type of staircase is known as a secondary spiral staircase, or Category A under BS5395.

Primary domestic spiral staircase should have:

  • 800mm clear tread width between the centre post and the inside of the handrail (900mm in Scotland)
  • Centre goings of 190mm minimum
  • No gaps greater than 99mm in the balustrade
  • No gaps greater than 99mm between the treads
  • Maximum riser height of 220mm
  • Typically used as the main staircase in a domestic property

A minimum 2000mm diameter spiral is required to meet this  (2100mm diameter in Scotland). This type of spiral staircase is only available as a custom made option, models such as the Apollo and Prisma are examples of this type of staircase. This is a Category B spiral staircase under BS5395.

What if you don’t have enough space for a full-sized spiral staircase?

K1 building regulations states that there is no minimum width requirement for a spiral staircase, but it should be built in accordance with BS 5395. In situations where space is limited, the diameter is at the discretion of the building inspector.

It is this clause that allows flexibility with the diameter, however we always suggest the client proceeds only with building controls agreement.

There is also discretion regarding the tread goings, so you may find that depending on your circumstances a non-compliant staircase is acceptable – always check this first with your Building Control Surveyor before proceeding, though.

The “100mm sphere” rule

All building regulation spiral staircases should comply with the 100mm sphere rule, i.e there must be no gaps greater than 99mm anywhere on the spiral staircase. Unfortunately this disqualifies a large number of attractive balustrade and staircase designs in the UK, leaving people with the more mundane vertical spindle designs, or expensive glass panel designs. However, your building control surveyor may still allow these types and designs of balustrade if you ask. The best bet is to do this by showing them the style of staircase you are interested in before buying and installing it.


  • Don’t assume a spiral staircase being sold in the UK automatically meets UK building regulations, always ask the supplier.
  • Get it in writing from the Manufacturer or Retailer if you want to be certain, you are then covering yourself if you have a problem in future.
  • Don’t forget you can always discuss your needs with building control, if a compliant spiral staircase can’t be fitted for any reason.


Buy a spiral staircase from Spiral Stairs Direct

For a great selection of spiral staircase designs, from low-cost budget to top-of-the-range custom options, contact us here.  We have a wide range of spiral staircases to choose from and can also offer design/consultancy, implementation and also the creation of a custom solution wherever it is required.









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