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STAIRS 3 rd YEAR TRADE. Lesson Two. M.S. MARTIN March 2005 Reviewed 2011. 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
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STAIRS3rd YEAR TRADE Lesson Two M.S. MARTIN March 2005 Reviewed 2011
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 = 171.428 say 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 Review Calculations
Revise Definitions • Handout • Complete names on handout & review on completion
Types of Stairs Ref: Carp 18 Textbook – from P6
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
Nosing line Wedge Detail & Size
Tenon Details Copy into your handout
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
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 Answer – note: this symbol √below means square root
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