Balau vs Chengal vs Kapur vs Keruing vs Khaya: Which Hardwood Timber Should You Choose?

Choosing the right hardwood timber for your project in Singapore comes down to four key factors: durability, strength, workability and cost. This guide covers five species commonly supplied in Singapore — Balau, Chengal, Kapur, Keruing and Khaya (African Mahogany) — each occupying a distinct position across these factors. Use it to make the right call for your specific application.

Species Comparison at a Glance

The table below summarises the key properties of each species to help you compare at a glance:

Species	Density (kg/m³)	Durability Class	Workability	Best Applications	Cost
Balau	800–1,100	Class 1–2	Moderate — interlocked grain, blunts tools	Structural construction, boat building, outdoor decking, flooring	$$$
Chengal	770–1,050	Class 1 (highest)	Moderate — resinous, care needed for finishing	Outdoor decking, bridges, heavy structures, marine environments	$$$$
Kapur	640–800	Class 2–3	Good — relatively easy to machine and plane	General construction, formwork, interior structures, joinery	$$
Keruing	720–900	Class 3–4	Moderate — resinous, variable gluing	Formwork, temporary structures, plywood production, framing	$$
Khaya (African Mahogany)	500–720	Class 3–4	Good — easy to machine, glue and finish; some tearout with interlocked grain	Furniture, interior joinery, cabinetry, decorative panelling, veneers	$$

Durability Class 1 = highest natural resistance to decay; Class 4 = least durable without treatment. Based on BS EN 350 tropical hardwood grading standards.

Species Deep Dive

Balau Timber

Density: 800–1,100 kg/m³  |  Durability Class: 1–2  |  Cost: $$$

Balau is the workhorse of Singapore's construction and marine timber industry. It is dense, extremely strong and naturally durable, making it one of the most widely specified hardwoods for demanding structural and outdoor applications.

Best used for:

•        Heavy structural construction and frameworks

•        Boat building and marine frames

•        Outdoor decking and flooring (typically with CCA or preservative treatment)

•        Utility furniture and industrial applications

Key consideration: Balau's interlocked grain can blunt cutting tools, and nailing or screwing requires care. For outdoor use, CCA or wood preservative treatment is recommended to extend service life to 10–20 years in exposed conditions.

Chengal Timber

Density: 770–1,050 kg/m³  |  Durability Class: 1 (highest)  |  Cost: $$$$

Chengal is widely regarded as the most durable tropical hardwood available in Singapore. Its Durability Class 1 rating means it is naturally resistant to decay, moisture, fungi and insects — even without chemical treatment. For applications where longevity is the primary requirement, Chengal is typically the first choice.

Best used for:

•        Outdoor decking and walkways (naturally resistant, no treatment required)

•        Bridges, heavy structures and infrastructure

•        Marine environments, jetties and pontoons

•        Long-service-life applications in humid or exposed conditions

Key consideration: Chengal is resinous, which requires care in varnishing, polishing and gluing. It commands a premium price over Balau, but this is often offset by its longer service life — untreated Chengal can last 15–25 years or more outdoors.

Kapur Timber

Density: 640–800 kg/m³  |  Durability Class: 2–3  |  Cost: $$

Kapur occupies the mid-range of the tropical hardwood spectrum. It is moderately strong, relatively easy to machine and cost-effective — making it the practical choice for general construction and interior applications where the extreme durability of Chengal or Balau is not required.

Best used for:

•        General construction framing and structures

•        Formwork and shuttering

•        Interior joinery, mouldings and panelling

•        Interior structural members

Key consideration: Kapur is Durability Class 2–3, meaning it is not suited for direct outdoor or ground-contact use without chemical treatment. For covered or interior applications, it is an excellent cost-effective alternative to Balau or Chengal.

Keruing Timber

Density: 720–900 kg/m³  |  Durability Class: 3–4  |  Cost: $$

Keruing is the most utilitarian of the four species — strong enough for structural use, economical in price and widely used for temporary works, formwork and plywood core production. It is not suited for outdoor or exposed use without treatment, but performs well in protected environments.

Best used for:

•        Formwork and temporary structures

•        Plywood and panel production

•        Internal framing and floor structures

•        Preservative-treated poles and piles

Key consideration: Keruing is resinous, which can make varnishing and gluing variable. Chemical treatment is recommended for any outdoor or moisture-exposed use. For formwork and temporary applications, it offers good structural performance at a lower cost point.

Khaya Timber (African Mahogany)

Density: 500–720 kg/m³  |  Durability Class: 3–4  |  Cost: $$

Khaya, commonly known as African Mahogany, is the only non-Southeast Asian species in this comparison. Native to tropical West and Central Africa, it is widely used in Singapore for interior furniture, cabinetry, decorative joinery and fine woodworking. Unlike the other species here, Khaya is valued primarily for its aesthetics and workability rather than structural strength or outdoor durability.

Khaya heartwood ranges from pale pink to a deeper reddish-brown, darkening with age. Quartersawn surfaces display a distinctive ribbon-stripe figure that makes it particularly popular for decorative veneers and visible interior panelling.

Best used for:

•        Interior furniture and cabinetry

•        Decorative veneers and panelling

•        Interior joinery, mouldings and trim

•        Boat interiors and cabin fitouts

•        Musical instruments and fine woodworking

Key consideration: Khaya is Durability Class 3–4 and is not suited for outdoor or structural applications without treatment. It can react with iron-based fasteners in damp conditions, so non-ferrous fixings are recommended. Its key advantage over the tropical species is its superior ease of finishing — it glues, turns, sands and polishes exceptionally well, making it the top choice for high-quality interior and decorative work.

Quick Selector: Which Species Is Right for Your Project?

Your priority is...	Best choice	Why
Maximum outdoor durability	Chengal	Durability Class 1, naturally decay-resistant
Structural strength + value	Balau	High strength, widely available, lower cost than Chengal
Interior / formwork on a budget	Kapur	Easy to work, cost-effective for non-exposed use
Temporary structures / plywood	Keruing	Practical and economical for short-term applications
Marine / waterfront with natural resistance	Chengal or Balau	Both rated for marine exposure; Chengal preferred untreated
Outdoor decking, budget-conscious	Balau (treated)	Good durability with CCA treatment at lower cost than Chengal
Interior furniture, joinery or decorative work	Khaya	Easy to finish, warm reddish-brown tone, excellent for fine interior work
Cabinetry, veneers or panelling	Khaya	Superior finishing properties and aesthetic appeal for visible interior surfaces

Does Your Hardwood Timber Need Chemical Treatment?

Whether treatment is required depends on the species and the application environment:

Species	Untreated outdoor use	Recommended treatment	Expected outdoor lifespan (treated)
Chengal	Yes — Class 1	Optional; SOLIGNUM or CCA for extra protection	20–30+ years
Balau	Yes — Class 1–2	CCA or preservative treatment recommended	10–20 years
Kapur	Not recommended	Chemical pressure treatment required for outdoor use	8–15 years (treated)
Keruing	Not recommended	Chemical pressure treatment required for outdoor use	8–12 years (treated)
Khaya	Not recommended	Interior use only recommended; preservative treatment if any moisture exposure	Interior use — service life depends on environment

Plony Industries is an authorised LONZA chemical treatment provider. Timber is pressure-impregnated with preservative under vacuum and high pressure at our own facility — ready for immediate use on delivery.

Frequently Asked Questions

Is Chengal worth the extra cost over Balau?

For applications where long-term outdoor durability is the priority — decking, marine structures, bridges — Chengal's natural Class 1 durability often justifies the premium. It can outlast treated Balau in exposed conditions and requires less maintenance over its service life. For structural or covered applications, Balau typically offers better value.

Can I use Kapur or Keruing for outdoor decking?

Not without chemical treatment. Both species are Durability Class 2–4 and will deteriorate quickly in Singapore's humid outdoor environment without preservative treatment. Even with treatment, Chengal or Balau are preferable for long-term outdoor decking.

Which hardwood is easiest to work with?

Khaya is the easiest of the five to work with — it machines, planes, glues and finishes exceptionally well, making it the preferred choice for fine interior and decorative work. Kapur is the most workable of the tropical species for general construction. Balau and Chengal are harder on equipment due to their density and interlocked grain. Keruing's resin content can cause issues with gluing and finishing.

Is Khaya (African Mahogany) suitable for outdoor use in Singapore?

No — Khaya is Durability Class 3–4 and is not suited for outdoor or exposed applications without chemical treatment. In Singapore's humid climate, untreated Khaya will deteriorate quickly outdoors. It is best used for interior furniture, cabinetry, joinery and decorative work where its excellent finishing properties and aesthetic appeal can be fully utilised.

What is the difference between Khaya and the tropical hardwoods like Balau or Chengal?

The key differences are origin, durability and intended use. Balau and Chengal are Southeast Asian tropical hardwoods valued for their high density, natural outdoor durability and structural strength. Khaya is an African hardwood valued for its workability, finishing quality and warm decorative appearance. Balau and Chengal are the right choice for outdoor, structural and marine work; Khaya is the right choice for interior furniture, joinery and decorative applications.

What is the heaviest tropical hardwood?

Balau has the highest potential density range (up to 1,100 kg/m³), making it the heaviest of the four species at the upper end. Chengal is close behind at up to 1,050 kg/m³. Both are significantly denser than softwoods commonly used in construction.

Supply of Hardwood Timber in Singapore

Plony Industries supplies all five species — Balau, Chengal, Kapur, Keruing and Khaya — in standard and custom dimensions, with in-house cutting, planing and LONZA-authorised chemical pressure treatment.

•        Cut-to-size and custom dimensions

•        Chemical pressure treatment (LONZA authorised)

•        Fire retardant treatment available

•        Island-wide delivery across Singapore

Contact us for enquiries: +65 63665855  |  cs@plonyindustries.com

Website: www.plonyindustries.com/hardwood-timber