Steel Stair Stringer Cutting Template Guide for Welders

What a stringer cutting template does

A stair stringer carries the treads and risers, so every notch has to sit at the same height and depth. A cutting template is a reusable pattern, usually made from thin sheet or board, that shows the exact outline of the stringer. Instead of measuring each cut from scratch, the welder lays the template on the channel and marks the same profile every time.

On site, this matters because stairs often have to fit between finished walls, and small errors in notch height add up quickly across the whole flight.

Gather the site dimensions first

Before drawing anything, confirm the finished floor levels at the top and bottom of the flight. Measure the total rise, the total run available and the width between supports. Note the planned tread thickness, because it changes the height of the first and last riser.

• Total rise from finished floor to finished floor
• Available horizontal run
• Stringer length and channel size
• Landing or platform position

Record these figures on paper and check them twice. The engineer or architect should confirm the final levels before cutting begins.

Draw the full-scale profile

Lay out the stringer on a flat surface at full scale. Mark the baseline and draw the riser and tread lines from the calculated values. Keep the drawing neat, because it becomes the source for the template.

Check that all risers are equal in height and that the top and bottom steps match the landings. Small errors at this stage are easy to correct on paper and expensive to correct after cutting.

Build and check the template

Transfer the profile to thin sheet or sturdy board and cut it accurately. Smooth the edges so the template sits flat against the channel without rocking. Mark the template with the stair position, the flight direction and whether it is the left or right stringer.

Test the template by laying it against a short piece of channel and checking the notch corners with a square. Adjust the template before using it on the real steel.

Transfer the template to the steel

Clamp the template firmly to the channel and mark the cut lines with a sharp scriber or marker. Check the marks for alignment on both flanges of the channel. Where the stringer will be welded to the landing or top support, mark the weld positions as well.

• Mark both sides of the channel
• Mark the centre of each notch
• Label each piece before cutting

Cut, fit and confirm

Cut along the marked lines and dress the edges with a grinder so the fit-up is clean. Set the stringers in position and check the levels before final welding. Stair details such as handrail fixings and guard positions should follow the standards and the engineer's drawings. Exact values for guardrail heights and loads are checked with the engineer.

Once the fit is confirmed, complete the welds and finish the steel as specified.

Frequently asked questions

Can I use a template for both stringers in a flight?

Yes, if the stairs are identical and the template is marked clearly for each side. Mirror the template for the opposite stringer and check the orientation before marking.

What material is best for the template?

Thin sheet metal or a rigid board works well, as long as it is flat and straight-edged. Choose a material that will not warp when handled on site.

Why do my stair treads not sit level?

The most common cause is unequal notch heights or a template that was not square to the channel. Recheck the layout against the measured levels.

Do I need an engineer for stair stringers?

Stair structures should follow the approved drawings and standards, so the engineer should confirm the design and the required values before fabrication.

Common mistakes to avoid

Cutting before confirming the finished floor levels is the most costly error, and a template that is not checked square will carry the same error into every stringer. Always test the template on a short piece of channel first.

Our recommendation

Make the template from measured on-site levels, not from the original drawing alone, and check it against the landing before cutting the steel.

Summary

A careful steel stair stringer cutting template, built from confirmed site levels and checked before use, produces consistent stringers that fit the flight.

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