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 na · a = L and compare with the size at the stairwell (2090 mm). L = na · aL = 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