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		Stairmaking - Course: Timberwork techniques. Instruction examples for practical vocational training (Institut für Berufliche Entwicklung, 34 p.)
			(introduction...)
			Preliminary Remarks
			Instruction Example 8.1.: Taking off Dimensions at the Stairwell
			Instruction Example 8.2.: Determination for the Ratio of Rise and Tread
			Instruction Example 8.3.: Scribing of landing connections
			Instruction Example 8.4.: Manufacture of Template and Angular Board
			Instruction Example 8.5.: Scribing and Preparing the Stair Strings
			Instruction Example 8.6.: Manufacture of Steps and Risers
			Instruction Example 8.7.: Assembly of the Stair Flight

Instruction Example 8.2.: Determination for the Ratio of Rise and Tread

The dimensions given below have been taken off the stairwell and entered into the hand-sketch.

Details of the stairs to be built in:

- straight stairs with two branches of flights, mortised
- string thickness: 50 mm
- riser thickness: 15 mm
- floor thickness main landing: 24 mm

, ns = 8

Auxiliary accessories

Paper, pencil, slide rule or calculator/computer

Necessary previous knowledge

Fundamental arithmetics: adding, subtracting, dividing, multiplying

Explanations to the working drawing

(1) main top landing

(2) main bottom landing

(3) half-landing

(4) upper edge of bare ceiling

Sequence of operations

Comments

1. Sequence stair height for one branch of flights.

Divide the measured floor-to-floor height by two.

2. Determine the height of rise.

s=171 m

3. Check the flight length.

Start from the size n_a · a = L and compare with the size at the stairwell (2090 mm).

L = n_a · a
L = 7 · 290 mm L = 2030 mm

The difference of 60 mm is to be compensated at the top landing connection!

4. Check the half-landing height.
Gh + d₁ - d₂ ⁼ Lh!
1410 mm + 24 mm - 40 mm =
1394 mm ¹ 1368 mm

Check from the main top landing.
Lh = 1368 mm!
Half-landing is to be raised!

5. Find out the difference.
1394 mm - 1368 mm = 26 mm

Half-landing is to be raised by 26 mm. Half-landing is not removed but 26 mm thick boards are put on before the floor is constructed!

Determination of the Ratio of Rise and Tread

Sequence of operations	Comments
1. Sequence stair height for one branch of flights.	Divide the measured floor-to-floor height by two.

2. Determine the height of rise.
s=171 m
3. Check the flight length.	Start from the size n_a · a = L and compare with the size at the stairwell (2090 mm).
L = n_a · a L = 7 · 290 mm L = 2030 mm	The difference of 60 mm is to be compensated at the top landing connection!
4. Check the half-landing height. Gh + d₁ - d₂ ⁼ Lh! 1410 mm + 24 mm - 40 mm = 1394 mm ¹ 1368 mm	Check from the main top landing. Lh = 1368 mm! Half-landing is to be raised!
5. Find out the difference. 1394 mm - 1368 mm = 26 mm	Half-landing is to be raised by 26 mm. Half-landing is not removed but 26 mm thick boards are put on before the floor is constructed!