Expansion Joint Design in Aluminum and Steel Cladding

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Expansion joints in aluminum and steel cladding allow panels to expand and contract with temperature changes without buckling, cracking or loosening fixings. Aluminum moves considerably more than steel for the same temperature change, so joint width, spacing and sliding fixings must be designed for the specific metal and the building's exposure. Joint positions are fixed during the drawing stage, before production begins.

Why thermal movement matters in cladding

Metal cladding expands in the sun and contracts at night, and the movement adds up across a long facade. Aluminum has a noticeably higher coefficient of thermal expansion than steel, so an aluminum panel run of the same length will grow more on a hot day. If that movement is not allowed for, the panels can bow, the sealant can tear, and the fixings can be overloaded.

The designer should consider the expected temperature range of the surface, not only the air temperature, since dark-coloured metal on a south-facing wall can get much hotter than the shade reading.

Planning joint positions and spacing

Joints are best placed at natural breaks in the design: at changes of plane, around openings, at floor levels and at regular intervals along long elevations. A continuous run of aluminum without breaks accumulates movement at its ends, so spacing should be set to limit the total length that moves as one unit.

Mark joints on the elevation before drawing details
Align joints with window and door frames where possible
Keep mixed-metal panels separated by a joint, since steel and aluminum move differently
Confirm the final spacing with the structural or facade engineer

Measuring the site and the building

Our process starts with on-site measurement of the actual openings, levels and substrate. Building tolerances are rarely perfect, so the drawing should reflect measured dimensions rather than design intent alone. We record the orientation of each elevation, the existing structure and any dimensions that depend on the adjacent trades.

Photos of the site, sent in advance with your inquiry, help us identify access and fixing conditions before the visit.

Drawing and written specification

After measurement we prepare a drawing showing each joint detail, the sliding or fixed fixing points, the sealant or cover profile and the joint width at the design temperature. A written specification accompanies the drawing and states the metal, finish, joint treatment and the installation sequence. This document is sent for your approval before any material is cut.

Clear joint details reduce disputes on site, because the installer, the contractor and the inspector all work from the same reference.

Production and finishing in the factory

Panels and profiles are cut and assembled in our Tel Aviv workshop at 37 Rival Street, where slotted holes for sliding fixings and the joint edges are prepared to the approved drawing. Finishing, including hot-dip galvanizing for steel and powder coating for both steel and aluminum, is carried out before delivery so that colour and surface are consistent across the facade.

Prefabricating the joint details in the workshop means fewer adjustments on site.

Installation and checking the joints

On site, fixings are installed to allow movement in the intended direction, and joints are set to the width shown on the drawing, adjusted for the temperature on the day of installation. Sealants and cover profiles are applied according to the specification. A final check confirms that no panel is restrained at a fixed point where it should slide.

Exact joint widths and fixing requirements should be verified with the engineer for each project, in line with the applicable standards.

Frequently asked questions

Do aluminum and steel cladding need the same expansion joints?

No. Aluminum moves more than steel for the same temperature change, so joint width and spacing are usually larger for aluminum. Each metal should be designed according to its own movement.

Where should expansion joints be placed on a facade?

Joints are typically placed at changes of plane, around openings, at floor levels and at regular intervals along long elevations. The exact layout depends on the building and should be confirmed with the engineer.

Can the joint width be decided after installation?

Joint width is set during design and adjusted at installation for the ambient temperature on the day. Changing it later is difficult, so it should be fixed in the approved drawing.

Do I need to send you drawings before starting?

You can send photos and any existing drawings with your inquiry. We measure on site and prepare our own drawing and specification, which you approve before production begins.

Common mistakes to avoid

A common error is treating a long aluminum run as one continuous panel with no joints, which causes buckling and sealant failure. Another is using the same fixing and joint detail for steel and aluminum without accounting for their different movement.

Our recommendation

Set joint positions on the elevation first, then size each joint for the metal's movement at the surface temperature you expect, and make sure sliding fixings are shown clearly on the approved drawing.

Summary

Good expansion joint design in aluminum and steel cladding plans for thermal movement from the start, placing joints at natural breaks and specifying sliding fixings for each metal. Measuring the site and approving a clear drawing before production keeps the installation predictable.

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