case study
Thermal expansion design rules for
Design Requirement
Why It Matters
Account for high CTE of austenitic grades
Stainless steel expands more than carbon steel and must be allowed to move. Prevents buckling, stress buildup, and noise.
Use fixed + sliding fastening strategy
Provide sufficient expansion joints Stainless steel panels can experience large ΔL under solar gain. Allow for solar thermal spikes Surfaces can exceed ambient by 30–70°C depending on finish. Control welding distortion High thermal expansion causes significant warping during fabrication. Use detailing that reduces friction Minimizes popping/creaking noises caused by restrained movement.
Aluminium expands significantly more. Stainless steel cladding must never be rigidly fixed to dissimilar materials without movement allowance, since otherwise joints tear or distort. Panel size, orientation and layout influence movement behaviour as mentioned earlier. Longer stainless steel panels undergo greater absolute expansion. This affects: • Joint spacing and required gap width • Maximum allowable panel length • Placement of fixed points • Orientation (vertical or horizontal movement direction) For metals in general, expansion must be integrated into the cladding system geometry. This implies that large stainless steel panels often require custom detailing, segmenting, or patterned systems to distribute movement. Welding distortion must be managed in stainless steel assemblies Stainless steel, especially austenitic grades, have both higher thermal expansion and lower thermal conductivity compared to carbon steel. This causes greater distortion during welding. Pre planning, heat minimising welding procedures, efficient jigging, and strategic tack weld sequencing are crucial for quality products with flat, visually critical façade panels. Since stainless steel is highly reflective, even minor panel deformation caused by thermal movement can be visually amplified. Azahner.com notes that thermal movement is a major factor in whether metal panels appear flat or buckle. Highly reflective finishes (e.g. mirror-polished stainless) demand especially careful detailing to maintain visual crispness.
Segment large panels
Reduces movement per panel; prevents oil canning
Stainless steel cladding Stainless steel’s distinctive aesthetic appeal comes with a structural obligation that its high thermal expansion must be engineered into every façade system. Proper detailing of the movement of joints, sliding fixings, solar temperature planning, and welding control, ensures that stainless steel cladding remains flat, quiet, durable, and beautiful over decades of environmental exposure.
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Issue 1 – 2026
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