Re-designing the staircase in your home can unlock a whole world of design potential. The new design must comply with Building Regulations Part K. The requirements are simple – stairs must be designed, constructed and installed so they are safe for people moving between different levels of the building.
However, there’s a bit more to it when you start looking… Here are the details to consider:
Steepness of stairs
This is calculated by measuring the rise (ie the height of each individual stair) and the going (also known as the tread) (ie the depth of each individual stair). As a general rule the acceptable range for domestic stairs is:
- Rise 150 mm to 220 mm
- Going 220 mm to 300 mm
The maximum pitch for a domestic stair is 42°; the relationship between the rise and going should be: twice the rise + the going = between 550 mm to 700 mm.
Construction of stairs
- Steps are to be built with level treads
- The rise and going of each step should be consistent throughout the flight of stairs*
- Steps may have open risers if:
- The riser overlaps the tread by at least 16 mm
- A 100 mm diameter sphere can’t pass through the open risers
Headroom for stairs
There must be at least the headroom shown in the below diagram. See Part K for more.
For loft conversions the headroom can sometimes be reduced to 1.9 m in the centre of the stairs.
The landing at the top and bottom of every flight;
- must be at least the size of the smallest width of the flight
- must include part of the floor of the building
- should be level; and kept clear of obstructions
- may have doors to cupboards that open over the landing at the top of the flight, if kept shut.
A door may swing across a landing, at the bottom of a flight, as long as there is 400 mm between the step and the max point of the door swing.
Long stairs –
if more than 36 risers in consecutive flights (even separated by landings), ensure one change of direction with an angle of at least 30°.
Special rules apply (not dealt with here)
Alternating tread stairs (a.k.a ‘hit and miss’ or ‘paddle’ stairs)
These should only be used:
- in loft conversions and
- where insufficient space to satisfy the general rules and
- where they only lead to one habitable room (and bathroom) and
- with slip-resistant surfaces to the treads and
- with uniform alternating steps with parallel nosings and
- with a minimum clear headroom of 2m.
Tapered treads (going around a corner):
- For the going of the tapered tread, use the below diagram
- For consecutive tapered treads, use the same going
- If there are straight and tapered treads, the going of the tapered treads should not be less than that of the straight treads
Handrails for stairs
Many stairs on Pinterest and Houzz aren’t from the UK and don’t comply with the handrail or guarding rules – so beware of Pinterest Pipe Dreams
- Position the top of the handrail 900mm to 1000mm from the pitch line or floor.
- May form the top of a guarding if the heights comply with the above.
- Must be on both sides if the stairs are 1000mm or wider
Guarding of stairs
Guarding is needed on stairs and landings when there is a drop of more than 600mm.
- Must be min 900 mm high internally and 1100 mm high for all external edges
- Must ensure a 100 mm diameter sphere can’t pass through any openings (so that a toddler can’t get their head stuck…)
- Prevent children from being able to climb the guarding
*Fun fact as a reward for getting this far: Stone-masons sometimes used to deliberately include a lower height step in castle staircases. Castle residents would know the be careful of the step next to the window, but attacking incomers would trip over on their way up, making them vulnerable to attack!
For advice on reconfiguring your stairs, get in touch!