STAIRS3rd YEAR TRADE

Lesson Two

M.S. MARTIN

March 2005

Reviewed 2011

M.S. MARTIN

March 2005

Reviewed 2011

Review Calculations• Determine suitable rise &

going of step to construct a closed riser timber staircase given the following.

• Rise of flight – 2.400m• Going of flight – 3.900m• Assume rise of – 170mm

• No. Risers = 2.400 .170 = 14.117 say 14

• Height of Riser= 2.400 14= 171.428say 171

• No. of Goings = 13 (one less)• Length of going

= 3.900 13= 300

• Check for easy going 2R + G = 550 to 700 (2 x 171) + 300 = 642 OK

Revise Definitions

• Handout

• Complete names on handout & review on completion

Types of Stairs

Ref: Carp 18 Textbook – from P6

Straight Open Riser

Dogleg

Quarter Turn

Geometrical circular

Spiral or Helical

Types continued – from P5 - 9

• Review text for type combination

• Brick• Concrete• Steel or Iron• Other types• Timber

BCA

• Your 2011 workbook on stairs (first section)

• Your text and other printed information, makes frequent reference to BCA requirements, review some of these in the handout

Timber Stairs

Ref: Carp 18 textbook – P25 – 29

Open Riser Stair

• From P27• Also your first

practical exercise• Review these few

pages in your textbook

Closed Riser Staircase

• Your 2011 workbook from P 36

• Review Handout, this will be your second practical project

Rise of step

Margin line

Closed Riser Stair Set - out

Wedge Detail & Size

Nosing line

Tread Detail of Housings

Closed Riser Staircase

Template you made in the workshop

Tenon Details

Copy into your handout

Newel set - out

Newel set – out continued, also P23 carp 18

Stair calculations includinglength of string

Example P31 – carp,18

Stair calculations

• Review example of calculations on P31 of your textbook

Complete exercises

Workbook from P 17

“Extra” Calc’s exercise No. 1

• Copy the following and complete

• Calculate the quantity of timber required for the open riser stair with following spec:– Rise of flight 850mm– Going of flight 1.100m– String material 250mm x 38mm sawn H/W– Treads 40mm thick sawn H/W– Width of stair 1.200m– Assume rise 160mm

Answer – note: this symbol √ below means square root

• No. of Risers= .850

.160= 5.312 say 5 risers

• Height of riser= .850 = 170mm

5• No. of Goings = 4• Width of going

= 1.100 4

= 275mm• 2R + G

= (2 x 170) + 275 + 615 OK

• Length of string√ (rise of flight)² + (going of flight + one going of step)²

√ .850² + (1.100 + .275)²√ .850² + 1.375²√ .723 + 1.891√ 2.614= 1.617

• Order 1.8m lengths• String 250 x 38 H/W 1 @ 3.6• Treads 275 x 40 H/W 1 @ 4.8

• You don’t have to show all the working, but for this example it shows you the full answer

Calc’s Exercise No. 2• Copy the following & complete

• Calculate the timber order for a closed riser flight of stairs to suit the following spec:– Rise of flight 2.450m– Going of flight unrestricted try 280mm– Rise of step approximately 160mm– Riser boards 19mm thick maple, 20mm

nosing– Treads 40mm maple– Stringer 350 x 40mm Maple– Width of stairs 2.600m

Answer No. 2• No. of Risers

= 2.450.160

= 15.310 say 15 risers• Height of riser

= 2.450 = 163mm 15

• No. of Goings = 14• Width of going - unrestricted

= 280

= 280mm• 2R + G

= (2 x 163) + 280 = 606 OK

• Length of string√ (rise of flight)² + (going of flight + one going of step)²

√ 2.450² + (3.920 + .280)²√ 2.450² + 4.200²√ 6.003 + 17.640√ 23.643= 4.862

• Order 5.1m lengths• String 350 x 40 Maple 2 @ 5.1• Treads 300 x 40 Maple 7 @ 5.4