Manual of Purpose-Made Woodworking Joinery

94 Designing and making stairs to current building regulations

Balustrade

Figure 6.5: A balustrade is a protective barrier at the side

of a stair, landing or balcony, etc, usually comprised of

newel posts, handrails and balusters (sometimes referred

to as ‘spindles’) on wooden stairs, but which may also be

panelling, a wall, parapet, screen or railing, etc.

Deemed length

Figure 6.6: If consecutive tapered treads are of different

lengths, as illustrated below (when they extend into a

corner), each tread can be deemed to have a length equal

to the shortest length of such treads. Although not now

referred to in AD K1, the deemed length (DL) needs to

STAIR REGULATIONS GUIDE

Approved Document K1 (AD K1) of the current
Building Regulations (amended in 2010, but with no
substantive changes to the 1998 Edition and 2000
amendments – although further amendments are due)
governs the design of internal and external stairways
and balustrades, etc, in buildings and differentiates
between three categories: 1) private stairs, intended
to be used for only one dwelling; 2) institutional and
assembly stairs, serving a place where a substantial
number of people will gather; and 3) other stairs, for all
other buildings apart from categories 1 and 2.
The following modified version of AD K1 covers
most of the points concerning stairs and balustrades
only – and, by use of additional figured illustrations
and text in places, an attempt has been made to
present a clearer picture of stair regulations as a guide,
but not as a substitute.

Definitions

The following illustrated definitions are given to terms
used in AD K1 and a few others have been added
for greater clarity. As these are only basic definitions,
more explanatory information will be developed pro-
gressively throughout the chapter.

Alternating tread stair

Figure 6.4: This is a stair constructed of paddle- shaped
treads with the wide portion alternating from one side
to the other on consecutive treads.

The going is measured

between alternate

nosings

Handrail

on each

side

Going

NLT

220 mm

Rise

NMT

220 mm

Figure 6.4 A three- dimensional impression of an
Alternating Tread Stair.

* Non-entry area

for a notional

sphere of 100 mm

diameter

*

*

*

*

* * *

Figure 6.5 Protective balustrade on a stair and landing,

showing regulatory reference (*) to the spaces between

the balusters.

DL

= centre point for the

radial deemed length

(DL) and tapered treads

DL

DL

Figure 6.6 Application of Deemed Length (DL) for refer-

ence to other Regulations.