Manual of Purpose-Made Woodworking Joinery

110 Designing and making stairs to current building regulations

(b) tread- and riser- templates in position at the top

end of the string to illustrate additional marking out

required if the housings were being trenched out by

traditional hand operations. Figure (c) shows the fin-

ished appearance of the lower part of the string after

trenching or routering; and (d) shows the upper part

of the string with the top step in position.

Figure 6.37 shows a reliable method of transferring

the stepped- out divider marks from the wall string to

the outer string. This saves time and also reduces the

risk of cumulative errors that may arise from setting

out the strings separately.

Marking out the string tenons

Figures 6.38(a)(b)(c)(d)(e)(f ): The outer string seen

below in Figure 6.37 shows the position of the oblique

stub- tenons for jointing to the blind mortises in the

newel posts. The tenons on the right relate to the

top riser and the newel post positioned at the landing

level; the tenons on the left – which would normally

relate to the bottom riser if there was no protruding

step beyond the bottom newel post – relate, as shown,

to the second riser up, such being the case if (as was

quite common) the bottom step protruded past the

newel post.

Single, protruding bottom steps, with a traditional

bull- nosed end, a modern square- end, or a 45° splayed

end (as in Figures 6.24(b), 6.27 and 6.43), regardless

wall- string – i.e. if to be moulded to meet a moulded
skirting- shape. However, the margin should comfort-
ably accommodate the nosing projections without
bringing them nearer than 25mm to the string’s edge.

Setting out the stair strings

Figures 6.36(a)(b)(c)(d) and Figure 6.37: When
setting out the stair strings for the all- important
step- housings, first the margin line is pencil- gauged
along the face- side of the string. Then the pitch-
board is positioned at the base of the wall string to
mark the floor- line and the first riser of the bottom
step. A pair of dividers (as shown at Figure 6.32),
or a beam- compass, is opened out along the margin
line and is carefully set between the intersections at
finished- floor- level (FFL) and at the top of the riser.
This is the true hypotenuse of the step (if we ignore
the nosing projection), as clearly indicated at (H) in
Figure 6.33(a). The dividers are then carefully stepped
out along the line by the number of steps required.
The pitch- board is used again and the face lines of
the treads and risers are pencil- marked – care being
taken to relate each position of the pitch- board to the
equidistant divider- marks along the margin line.
Figures 6.36(a) and (b) illustrate the broken- length
parts of a wall string; with (a) the pitch- board cor-
rectly positioned above the marked- out steps (the only
marking out required if using a powered router); and

Figure 6.36 (a) Pitch- board in position at lower end of wall- string, one up from FFL – finished floor level; and (b) tread
and riser templates in position at upper end of wall string – one down from FFL; note the allowance left above FFL, to be
trimmed on site to suit the skirting height; (c) the appearance of the routered housings and the waste removed below FFL
(though this and the skirting abutment are done on site); (d) an illustration of the last fitted and wedged step at the top of
the wall string – note that the very top riser and the landing nosing- piece are also fitted and fixed on site.

FFL

FFL

Treads and risers marked from templates,

if trenching with a non-powered router

Finished appearance after assembly

Pitch-board related to divider-marks on

margin line of string, for marking face-

lines of the steps

Wall string after routering

FFL

FFL

(b)

(a)

(c) (d)