Why use hardwood for decking?
Hardwoods are naturally resistant to fungal growth and offer naturally superior levels of durability and wear resistance, without any additional chemical treatment, making hardwoods the ideal material for use in the construction of decking and outdoor furniture and structures. With limited maintenance using treatment oils they retain their natural beauty for many years. There are many types of hardwood available to use as decking, below is a list of the mosty popular.
Balau
General Description: The heartwood is yellow-brown, varying to brown and dark reddish-brown, with an interlocked grain and a moderately fine and even texture.
Mechanical Properties: Hard, heavy and very dense with a very high bending and crushing strength, and resistance to shock loads and high stiffness. It has a moderate steam bending classification requiring strong support on the outer face.
CumaruThe heartwood is reddish-brown or purplish-brown, with light yellowish-brown or purplish streaks when freshly cut, turning to a variegated reddish and yellowish-brown after drying, but on exposure to light assuming a uniform yellowish-brown or light brown colour. The sapwood is about 50mm wide, distinct from the heartwood and yellowish-brown in colour. The wood has a waxy or oily feel, a fine texture, and irregular and often interlocked grain. It is an extremely hard and heavy wood.
Mechanical Properties: Difficult - Cumaru is a heavy, hard, and tough wood which makes it rather difficult to work, but with sharp tools it saws and bores cleanly, and when severely interlocked grain is absent, planes and finishes to a smooth surface. It takes a high polish, but glues poorly.
Garapa
The sapwood is narrow and whitish in colour while the heart wood is mainly yellowish, varying from yellowish-brown to pinkish-yellow, tending to acquire a reddish or coppery hue after exposure. The wood is lustrous, with a straight grain (occasionally slightly interlocked) and a fine, uniform texture. The wood is hard, heavy, tough, and strong.
Mechanical Properties: The Garapa species, sometimes known as Brazilian Ash, is one of the finest quality hardwoods available that features a fine-grained timber that is yellow, often streaked with brown, becoming lustrous golden-brown to russet on exposure to the sun. Garapa is naturally resistant to rot, decay and insect attack. Garapa Decking offers a 25+ year lifespan without preservatives.
Ipe
Ipe's heartwood is olive-brown with lighter or darker streaks. The grain is straight to irregular with a low to medium lustre. The pores, appearing as fine yellow dots, or, on longitudinal surfaces as yellow lines, contain yellowish lapachol powder which turns deep red in alkaline solutions. The material is fine textured and appears oily; fine ripple marks may be present.
Mechanical Properties: The timber has very high strength in all categories, but is resistant to wood bending and has a moderate classification. Ipe is a strong, tough, resilient timber.
Iroko
Iroko is golden-orange to brown, lighter vessel lines are conspicuous on flat saw surfaces. The material may contain large, hard deposits of calcium carbonate in cavities, and the timber around them may be darker in colour. The grain is interlocked and sometimes irregular and the texture rather coarse, but even.
Mechanical Properties: Iroko's medium density timber has a moderate steam bending classification, with medium bending and crushing strength, very low stiffness and resistance to shock loads.
Massaranduba
Massaranduba's heartwood is light red to rose red when freshly cut, turning dark reddish brown on exposure; sapwood whitish or pale brown,distinct, but not sharply demarcated from the heart-wood. The grain is usually straight but sometimes interlocked, and the texture is fine and uniform. The timber is hard and extremely heavy.
Mechanical Properties: Medium to easy - Moderately easy to work despite its high density. It machines and finishes to a very smooth surface. The timber takes a fine polish and has the appearance of walnut. Gluing requires special care because of the wood's resistance to absorption of moisture.
Oak
European Oak's heartwood is light tan to biscuit coloured, usually straight grained, but irregular or cross-grained material can occur depending on growth conditions. Characteristic silver grain figure on quartered surfaces due to broad rays.
Mechanical Properties: Oak has a very good steam bending classification, but is liable to blue stain if in contact with iron compounds
Teak
The true teak of Burma is a uniform golden-brown colour without markings, but most other teak is rich brown with darker chocolate-brown markings. Indian teak is wavy grained and mottled, but generally straight to wavy grained, coarse textured, uneven, oily to the touch, and sometimes with a white glistening deposit.
Mechanical Properties: This hard, medium density wood has medium bending strength, high crushing strength combined with low stiffness and resistance to shock loads. It is fissile and brittle with great dimensional stability; it is fire and acid resistant. Teak can be steam bent to a moderate radius of curvature.
It is best to seek advice from a specialist supplier or contractor, so search the internet for decking companies and suppliers that have experience and can offer information and prices. Be sure of what you are buying and then enjoy a quality product that will add value and assessability to your garden.
Barry Holdsworth operates throughout the South East of England (London, Surrey, Sussex,Kent), the UK and abroad.