Overview of Finishes in Building Materials

Don't use the wrong finishes, or else!

Finishes in architecture serve two main functions: protection and aesthetics. They enhance the durability of materials, improve resistance to environmental factors, and contribute to the overall look and feel of a space. Choosing the right finish is as important as choosing the material itself, as incompatible finishes can reduce performance and even cause material failure.

This article provides a summary of common finishes, their correct applications on various building materials, and highlights commonly misunderstood or misapplied combinations.

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Types of Finishes

1. Paint

A liquid or mastic composition that, when applied to a surface, forms a protective and decorative coating.

• Acrylic Emulsion Paint – Used for interior walls and ceilings

• Enamel/Alkyd / Oil-Based Paint – Durable, used for timber and metal surfaces

• Epoxy Paint – Industrial-grade, highly resistant to chemicals and abrasion

• Intumescent Paint – Fire-resistant coating used on steel

2. Powder Coating

A dry finishing process where a free-flowing, dry powder is electrostatically applied and cured under heat. Provides a durable, uniform, high-quality finish.

3. Laminate

A thin layer of material (plastic, veneer, or film) bonded to a substrate. Commonly used for timber products, furniture, cabinetry, and interior wall panels.

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Common Building Materials and Compatible Finishes

Material	Suitable Finishes	Common Locations	Notes
Stainless Steel	Brushed, polished, hairline, bead-blasted	Railings, lift interiors, signage	Avoid painting unless special primers are used. Maintains self-protecting oxide layer.
Galvanised Steel	Paint (with primer), powder coat (if degreased and primed), epoxy coating	Railing, linkway/roof structures, fences, structural framing	⚠️ Powder coating directly over galvanised steel without surface prep can cause peeling (outgassing).
Aluminum	Anodising, powder coating, fluoropolymer coating	Facade cladding / rainscreens, window frames	⚠️ Painting directly on aluminum without etching primer leads to poor adhesion.
Timber	Stain, varnish, lacquer, oil, paint	Doors, feature walls panels, flooring	Depends on wood species. Softwoods often painted, hardwoods stained or oiled.
Plywood	Laminate, veneer, clear varnish, paint	Cabinets, wall panelling, ceilings	Interior-grade plywood may warp if improperly sealed.
Gypsum Board	Acrylic emulsion paint, wallpaper, skim coat	Interior walls and ceilings	Ensure joints and screws are flushed before finishing.

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Commonly Misunderstood or Misapplied Finishes

Incorrect Pairing	Why It’s a Problem	Better Alternative
Paint directly on aluminum	Poor adhesion due to non-porous surface	Use etching primer or anodise first
Powder coat on galvanised steel (untreated)	Outgassing during curing causes bubbles/peeling	Pre-treat by degreasing and passivating
Epoxy paint on raw timber	Doesn't penetrate wood grain well, peels easily	Use timber sealers or alkyd paint
Emulsion paint on metal	Low adhesion and durability	Use metal primer first

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Performance Considerations When Selecting Finishes

When selecting finishes, consider the following:

Consideration	Why It Matters
Material Porosity	Affects adhesion of paints and coatings
Environmental Exposure	UV, moisture, and salt exposure dictate finish durability
Maintenance Level	Some finishes (e.g. clear varnish) require regular reapplication
Fire Rating	Required in some materials like gypsum and steel framing
VOC & Sustainability	Low-VOC finishes are preferred for indoor air quality and green certifications (e.g. Green Mark, BCA Singapore)

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Conclusion

Finishes are not just cosmetic — they directly impact a building material's durability, performance, and compliance. Understanding the right finish for the right material is critical to delivering a building that stands the test of time and climate, especially in humid tropical climates like Singapore.

In future articles, we’ll dive deeper into performance-based selection of coatings, green-certified finishes, and detailing for long-lasting performance in architecture.