How to Repurpose Autoclaved Aerated Concrete for Furniture Making

How to Repurpose Autoclaved Aerated Concrete for Furniture Making

What is Autoclaved Aerated Concrete?

Autoclaved aerated concrete (AAC), also known as autoclaved cellular concrete (ACC), is a lightweight precast building material. It is made of cement, sand, water, and an expansion agent that causes the concrete to rise like bread dough. The material has an airy, foam-like structure and is lightweight while still being strong and insulating.

AAC is commonly used for walls, floors, and roofs in residential and commercial construction. However, due to its lightweight and workable nature, AAC also has potential for repurposing into furniture and other building projects.

Pros and Cons of Using AAC for Furniture

Using leftover or scrap AAC for furniture has several advantages:

  • Lightweight – The foamed concrete is lightweight, making furniture easier to move and transport.

  • Insulating – The air pockets in AAC provide thermal insulation, helpful for surfaces like tabletops.

  • Workable – AAC can be cut, sanded, and shaped relatively easily with basic tools.

  • Sustainable – Repurposing leftover AAC reduces waste and makes use of a material that would otherwise be discarded.

However, there are some downsides to keep in mind:

  • Brittle – While workable, AAC is quite brittle and can crack or chip if not handled carefully.

  • Unproven – There is limited information on best practices for furniture construction with AAC. Some trial and error is likely needed.

  • Aesthetics – The porous, rocky surface of AAC may not be appealing for some furniture designs. Requires finesse to achieve a clean look.

Preparing and Working with AAC

Before beginning a furniture project with AAC, it’s important to understand techniques for cutting, shaping, and finishing the material:

  • AAC can be cut with standard masonry saws or scored and snapped like tile. UseRespirators are recommended when cutting to minimize dust inhalation.

  • Sanding smooths and shapes AAC but should be done wet to avoid breathing dust. Begin with coarse grit sandpaper, finishing with fine.

  • Sealing AAC with concrete sealers or epoxy resins can help strengthen, waterproof, and provide aesthetic finishes like gloss.

  • Supporting AAC properly is crucial for furniture. Designs may require internal reinforcements or frames for adequate strength.

Furniture Designs and Ideas

Some furniture types that are well-suited for AAC:

  • Tables – The lightweight nature of AAC makes it feasible for tabletops. Edge treatments can refine the look.

  • Shelves – The rectilinear blocks of AAC are ideal for open box-style shelves. Again, edging and framing helps.

  • Benches – Simple rectangular benches are an option, as AAC can comfortably support seated weight when properly reinforced.

  • Planters – The water-resistance and insulation of AAC are useful for indoor planter boxes and pots.

  • Decor – Smaller decorative objects like vases, candleholders, and trays can highlight the quirky visual texture of AAC.

The possibilities for repurposing AAC into furniture are extensive. With smart design and construction techniques, leftover AAC can be diverted from landfills to become unique and functional furnishing projects.