What is aluminum foam? A short guide for architects and designers

Aluminum foam is exactly what the name says: aluminum, with gas cells inside it. It is made by foaming the molten metal so that it sets with a structure of closed cells, then sawing the resulting billet into panels. The result is a material that is metal through its whole thickness, but at a fraction of the weight of a solid aluminum plate of the same size.

How it is made

Molten aluminum is treated so that gas forms inside it while it is still liquid. The foam rises, is held at the right point, and is cooled into a billet. The cell structure is fixed at this stage: the size of the cells, how evenly they are distributed, and the proportion of metal to void. Billets are then sawn into panels. Every saw cut opens a new face of cells, which is why the surface of a panel looks the way it does, and why no two panels match.

Closed cell, not sponge

There are two families of metal foam. Open-cell foams look like a metal sponge: the cells connect, and air passes straight through. Closed-cell foams, which VORALOY panels are, have cells that are sealed from one another inside the panel. The sawn surface shows the cells that were cut open, but the body of the panel is not porous in the way a sponge is. This matters for how the material behaves outdoors, how it is cleaned, and how it reads as a surface.

Cell grades

Panels are sorted by cell size into three grades. Fine reads as an even, almost granular texture at room distance. Medium is the general-purpose grade, where individual cells are visible and the surface has clear depth. Coarse is the most sculptural, with large open cells and strong shadow. The same 20 mm panel system carries all three, so a project can move between grades without changing the detail.

What a panel is like in hand

• Weight. Noticeably lighter than it looks. People pick it up expecting cast metal and get something closer to timber.
• Surface. Raw sawn aluminum: matte, slightly silver, with the cells cut open. There is no coating. The surface is the material.
• Edges. Sawn edges show the cell structure in section. They can be left raw, eased, or framed in aluminum, timber or steel.
• Working it. It cuts with ordinary woodworking tools, drills cleanly, and fixes with standard screws and adhesives. A joinery shop can handle it.

What it is not

It is not a laminate, a honeycomb, or a perforated sheet. Those are assemblies with a skin and a core; aluminum foam is one material. There is nothing to delaminate, no skin to scratch through, and no coating to peel. It is also not a precision-cast product: cell size and placement vary naturally from panel to panel, and that variation is part of the surface.

Where it is used

Facades and entrances, interior walls and partitions, ceilings and acoustic spaces, roadside noise barriers, and furniture and objects. Each use leans on a different property: being non-combustible outdoors, being light overhead, being a cellular surface where sound matters, or simply being a metal you can saw to the piece. See Applications for each in turn.

How to buy it

VORALOY sells aluminum foam by the panel. Sample Kits are ordered online; standard panel sizes and custom cutting are quoted per project. Performance figures such as fire ratings and acoustic absorption depend on the assembly, so we document them per project rather than printing one number for the material.

Hold the material before you decide. The Standard Sample Kit is one 300 × 300 × 20 mm panel; the Designer Kit is three cell grades side by side. Both ship free within the United States.