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The balanced staircase is often considered a difficult work. However, the construction of this ash staircase is accessible, provided to provide a detailed layout and to have power tools.

### Necessary material

• Mallet
• Hammer
• Wood chisel
• bracket
• Bevel
• réglet
• Spirit level
• Clamps
• Planer Thicknesser (or planed panels ready for use)
• Circular and Jigsaws
• Screwdriver drill
• Domino milling machine or drill
• Eccentric sander
• 5 m² solid ash planed ep. 30 mm
• 3 m² solid ash or poplar planed ep. 20 mm
• Wood screw 3 x 40/5 x 60/6 x 100 mm
• Anchors 10 x 60 mm
• Thin stick type quarter round
• 25 mm tips
• Angled ramp support

Difficulty: 3/4
Cost: 700 €
Time: 10 days
Find the plan of this realization on duitdesign.com/boutique

A quarter-turn staircase is pleasant to take when the width of its steps is properly balanced. Its design, however, requires careful preparation.

## Strict basic rules

For such a staircase to be easy to climb and descend, two measures must remain constant: the height of the steps and the width of the tread.
They are calculated at the right of the stride line, that is to say the path theoretically taken in the staircase: 50 cm from the outside wall.

• The height of the stairs is calculated by dividing the total height (of the landing bearing) by a whole number of steps.
• The available footprint for the stairway determines the length of the treads.
• In order to verify the comfort of such a work, the formula of Blondel is applied: 2 heights + 1 lap = the average amplitude of the human step (between 58 and 64 cm).

## The hold of the stairs

An interior staircase inclined between 25 and 35° is considered comfortable when its width is greater than 80 cm, its walking height is less than 17 cm and its upper bead is 27.5 cm. It is felt stiff when it displays a walking height of more than 19 cm and a tread of less than 25 cm. The dimensions of the hopper also determine the proportions of the staircase, in particular its inclination. And to avoid bumping your head, you have to check that the height of the breakaway is at least 1.90 m.

## For further

There are different methods to achieve a balanced staircase (harrow, alignments, trapezium proportions...). A book may be useful to consult: Construction of wooden stairs by Andy Engel (Editions Eyrolles).
If the manufacture of this type of staircase seems inaccessible to a large number of do-it-yourselfers, it remains then the models in kit, to be assembled oneself. Just take the right odds and consult a few distributors to refine your project.

## Preparation of the steps

• The planks are built and assembled (tongue and groove, false tongue or sawtooth) to obtain panels wide enough to form the steps.

• Machine assemblies according to available tools (ripper, laminator, router...).
• Glue and press the steps (eleven total in more than half a millimeter) and, if necessary, silt.
• Use for this purpose simple or dormant clamps.

## Info for DIYers

If you plan the wood yourself, let the rough planks cut and cut long on cleats for a week.
This makes it possible to stabilize the wood at room temperature before making the work.

## Post machining

The post consists of three boards (30 mm thick) assembled in "L" by pigeons and glued together to obtain a seat wide enough to receive the steps.

• On one of the faces of the post, trace the grooves intended to contain the end of the balanced steps.
• Measurements are reported from a dimensioned plan.

• With a router equipped with a straight cutter of Ø 30 mm, machine grooves of 15 mm of depth in the layout.
• A template, flanged on the post, allows to guide the machine with precision. Its stroke is limited in length by stops.

• A similar device is used to machine the vertical grooves of the risers with a Ø 20 mm cutter.

• Wedge the 30 mm grooves with a chisel according to the shape of the stair nosing.
• Do the same for the fitting of the run and riser grooves.

## Cutting of silt and steps

• The silts support steps and risers screwed on.
• The layout of the cuts is made with a false square whose angle can be directly adjusted from the sketch.

• For a precise pattern, press the false square on the reference edge and transfer the dimensions with a ruler to form the rack line of the cut.

• Draw arcs (R = 7 cm) whose center is at the junction of the cutouts of the steps and risers.

• Point a flexible rule to form a regular curve.

• Cut the loam with a circular saw.
• The cutouts of the steps are 90°.

• For risers, the saw should be tilted at the angles indicated on the plan.

• Line the bottom of the nose with the ripper with a quarter round cutter, then with a straight cutter to create the groove of the riser.

## Tip for DIYers

The layout of the steps and strings is normally done on a life-size map drawn on the floor or on a wall. This method requires a large room and a certain habit. Otherwise, do not panic! Design assistance software is freely available on the Internet. They will help you realize and dimension your drawings with great precision.

To know more:
stairdesigner.org
sketchup.com/fr
draftsight.fr

## Setting up the stairs

• Make a removable assembly between stringers and post.
• To avoid the classic tenon and mortise, use pigeons or trunnions.

• Thread and screw the stringers against the wall.
• Fix the post after having stalled so that the steps are perfectly level.

• Climb risers and steps starting at the bottom.
• A bead of polyurethane glue avoids squeaks (when swelling, the glue forms a flexible joint).

• When they are not inserted into the grooves of the post, the ends of the steps are screwed onto the stringers.

• Also secure the back of risers and steps with screws spaced about 15 cm apart.

• The last step is called the plate. It is generally narrower than the previous ones.
• Adjusted to the floor, it is assembled by pigeon.

## A homemade truscan to realize the ramp

• After cutting the silt, use a chute to draw a ramp using a truscan.
• This tool is quite simple to manufacture with a wedge and two trunnions.
• The space between the hole and the trunnions will correspond to the thickness of the handrail.

• Place a pencil in the hole, trace, then cut.
• The ramp (sanded and chamfered) is then fixed to the wall by means of an angled boom support.