Hardwood Windows

Environmental

Listed in the IUCN Red List of Threatened Species as Vulnerable (VU): at risk of extinction. Believed available from well-managed sources.

Distribution

It is found in the rain forests of West Africa from the Ivory Coast through Ghana and Nigeria to the Cameroons. It also extends eastwards to Uganda and Tanzania.

The Tree

A very large tree with cylindrical bole and small or no buttresses. Grows to a height of 45m or more, with a diameter at breast height of 10m or slightly more.

The Timber

The sapwood is pale yellow or whitish, the heartwood pinkish when freshly cut, darkening to the typical mahogany colour of reddish-brown. Sapele is characterised by a marked and regular stripe, particularly pronounced on quarter-sawn surfaces. Occasionally mottle figure is present. It is fairly close textured and the grain is interlocked. It is harder and heavier than African mahogany, weighing about 640 Kg/m³ when dried. It has a pronounced cedar-like scent when freshly cut.

Drying

The timber dries rapidly with a marked tendency to distort. Quarter-sawn material is less liable to degrade in drying.

Strength

Sapele is much harder than African or American mahogany, and in resistance to indentation, bending strength, stiffness and resistance to shock loads, is practically equal to English oak.

Working Qualities

Medium. Works fairly well with hand and machine tools, but the inter-locked grain is often troublesome in planing and moulding, and a reduction of cutting angle to 15° is needed to obtain a good finish. It takes screws and nails well, glues satisfactorily, stains readily and takes an excellent polish.

Durability

Moderately durable.

Treatability

Difficult.

Moisture Movement

Medium.

Density (Kg/m³)

640.

Texture

Medium.

Use(s)

Joinery (interior and exterior), furniture and flooring.

Colour(s)

Pink/pale red (when freshly cut), reddish brown (typical mahogany colour).

Environmental

Many species of Shorea appear on the IUCN Red List of Threatened Species and are classified as:

• Critically Endangered (CR): at very high risk of extinction in the wild.
• Endangered (EN): at high risk of extinction in the wild.
• Vulnerable (VU): at risk of extinction.

Not listed in CITES. Believed available from well-managed sources.

Distribution

Malaysia.

The Tree

The various species of Shorea grow to a height of 45m or so and a diameter of 1.2m or a little more, with long, clean, cylindrical boles above small buttresses.

The Timber

Sapwood is lighter in colour and distinct from heartwood which is red-brown darkening to a dark red. Planed surfaces are fairly lustrous, with stripe figures on radial surfaces. Grey-coloured narrow streaks are often present on all longitudinal surfaces, caused by concentric layers of resin canals. The texture is rather coarse but even, and the grain is interlocked and wavy.

Drying

The various types of meranti/seraya are reported to dry rapidly and well, with little degrade. Some slight distortion and surface checking may occur in the denser types. ‘Malayan Forest Service Trade Leaflet No 8’ gives the following information regarding the air drying times for red meranti dried under cover in Malaysia. From about 60 per cent moisture content to 18 per cent moisture content:

• 25mm boards 2 to 3 months.
• 38mm boards 3 to 4 months.
• 50mm boards approximately 5 months.

Strength

There is a wide variation in the strength properties of the various merantis and red seraya due to the differences in density and the number of species involved. Large, over-mature logs are frequently spongy in the heart, the wood in these areas being weak and brittle. Despite the fact that the best type of light red meranti is almost equal in strength to the weakest type of dark red meranti, there is nevertheless on average, a distinct difference in mechanical properties. The average figure for strength and stiffness in bending and compression for dark red meranti is about 20 per cent higher than that for light red meranti. In shear, there is about a 10 per cent difference and in hardness, over 30 per cent.

According to data from the Malayan Forest Service, light red meranti is almost equal to oak in strength properties, but oak is much harder, while Scots pine has only about 75 per cent of the general strength of light red meranti. White and yellow meranti are reported to have similar properties to those of American mahogany but with lower resistance to splitting in the tangential plane in the case of white meranti.

Working Qualities

Medium. The wood of the various species works well and in general, is capable of a good smooth surface, but a reduction of cutting angle to 20° is beneficial where a tendency for the grain to tear becomes apparent. The dulling effect on saws and cutters varies somewhat with the species, but is usually quite small, except in the case of white meranti which generally contains a fairly high amount of silica in the ray cells. The various species can be glued, nailed and screwed satisfactorily, and can be stained and polished quite well after suitable filling.

Durability

Slightly durable (can vary in durability).

Treatability

Extremely difficult (moderately easy for sapwood).

Moisture Movement

Small.

Density (Kg/m³)

710 (Density can vary by 20% or more).

Texture

Medium.

Use(s)

Available at specialist timber merchants.

Colour(s)

Reddish brown (medium to dark in shade) and red.

Environmental

Not listed in CITES. Believed available from well-managed sources.

Distribution

Throughout Europe including the British Isles, extending into Asia and North Africa.

The Tree

Reaches a height of 18m to 30m or a little more depending upon growth conditions which also affect the length of the bole. When drawn up in forests at the expense of their branches, this may be 15m or so in length, but in open situations, the tree branches are much lower down. Diameters are about 1.2m to 2m.

The Timber

There is no essential difference in the appearance of the wood of either species. The sapwood is 25mm to 50mm wide and lighter in colour than the heartwood which is yellowish-brown. Quarter-sawn surfaces show a distinct silver-grain figure due to the broad rays. The annual rings are clearly marked by alternating zones of early wood consisting of large pores, and dense late wood. Conditions of growth accordingly govern the character of the wood to a great extent. For example, in slowly grown wood the proportion of dense late wood is reduced in each annual growth ring, thus tending to make the wood soft and light in weight. The growth conditions in the various countries that export oak vary considerably. Baltic countries, including northern Poland, produce oak which is generally hard and tough, but further south in Poland, the growth conditions become more favourable to the production of milder, more uniformly-grown oak. The rich black soil of southeast Poland produces the famous Volhynian oak. The character of this type of wood changes a little in countries in Central Europe, such as Czechoslovakia and Hungary, but is generally a little milder in character in Yugoslavia, from whence Slavonian oak is shipped. The weight of oak varies according to type. Oak from the Baltic area, western Europe and Great Britain is about 720 kg/m³ and that from Central Europe is about 672 kg/m³ on average after drying. So-called brown oak is the result of a fungus attack in the growing tree. The fungus, Fistulina hepatica, causes the wood first to assume a yellow colour, then a richer brown or reddish-brown. A yellow-coloured streak sometimes appearing in oak is the result of another fungus, Polyporous dryadeus, but since very few tree diseases persist after the tree is felled, dried timber is no different from normal-coloured wood. Indeed, brown oak is often preferred for its decorative appeal.

Drying

Oak dries very slowly with a marked tendency to split and check, particularly in the early stages of drying and there is a considerable risk of honeycombing if the drying is forced, especially in thick sizes. End and top protection must be provided to freshly sawn stock exposed to sun and drying winds, and sticker thickness should be reduced to about 12mm for stockpiles in the open air during early spring and onwards until winter.

Strength

Both the sessile and pedunculate oaks have well-known and high-strength properties, and those hybrid oaks developed from both types and common throughout Europe are similar in their strength properties. Note: In BS 5268-2: 2002, there is a discrepancy between Tables 7 and 15 regarding characteristic density and strength classes for use in joint design. The values quoted here should be used, rather than those included in the 14 March 2002 edition of the code.

Working Qualities

Medium to difficult. The working and machining properties of oak vary with the mild to tough material which either machines easily or with moderate difficulty. These basic properties are concerned with growth conditions, but they may be exaggerated by indifferent drying methods which allow plain-sawn boards to cup or severe case-hardening to develop, causing excessive wastage in planing and moulding, cupped stock in resawing, and a greater degree of blunting of cutting edges. These must be kept sharpened, particularly where cross-grain is present and especially in planing highly-figured quarter-sawn surfaces where there may be a liability for the grain to tear out at the juncture of the wide ray-figure, thus producing a shelly appearance. In general, oak finishes well from the planer or moulding machine, although in some cases a reduction of the cutting angle to 20° is preferable. The wood can be stained, polished, waxed and glued satisfactorily, takes nails and screws well (except near edges, when the wood should be pre-bored) and also takes liming and fuming treatments well.

Durability

Durable.

Treatability

Extremely difficult (easy for sapwood).

Moisture Movement

Medium.

Abrasions

Very good.

Density (Kg/m³)

720 (Density can vary by 20% or more).

Texture

Medium to coarse.

Use(s)

Heavy structural use, cladding, joinery (interior and exterior), furniture, flooring, sleepers and decking.

Colour(s)

Yellow brown.

Environmental

Listed in the IUCN Red List of Threatened Species as Vulnerable (VU): at risk of extinction.

Distribution

Occurs in Equatorial Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana and southern Nigeria, as well as in parts of the rain forest and throughout the deciduous forest areas.

The Tree

A tall tree with a buttressed trunk attaining a height of over 30m and commonly 1.0m or more in diameter. The buttresses are broad and blunt, but the bole is usually clean and straight, 20m or more above the buttress.

The Timber

A plain, pale yellow to light brown coloured wood. Sometimes relieved by a zonal figure originating in the growth rings, suggesting plain oak. There is little distinction between sapwood and heartwood, though the latter is somewhat darker in colour. The grain is straight to slightly irregular and the texture is somewhat coarse and uneven. It is soft to medium hard and weighs about 560 kg/m³ when dried. The weight is often variable, due to a prevalence of lightweight brittle-heart, particularly in large, over-mature logs. It may vary from 480 to 625 kg/m³ but for general assessment, the average dry weight is as given.

Drying

Idigbo dries readily and well, with little distortion and splitting, and shrinkage is small.

Strength

It has excellent strength properties, being as strong and stiff as English oak in bending, although considerably softer and less resistant to shock loads. It splits easily and has been used in West Africa for roof shingles. When converting large logs the heart should be boxed out as the brittle heart has very much lower strength properties than the normal wood. In freshly converted stock, brittle heart may often be recognised by a distinctive pinkish colour which may develop after exposure to light for a few days. Natural compression failures, often referred to as “thunder shakes” usually accompany brittle heart.

Working Qualities

Medium. The timber works easily with most hand and machine tools. It has little dulling effect on cutting edges and a clean finish is obtained in most operations. There is a tendency, however, for the grain to pick up when quarter-sawn material is planed and a reduction of cutting angle to 20° or less is advisable where smooth surfaces are required. Idigbo turns well and has fairly good nail and screw-holding properties and will take glue well. It also stains effectively and reacts well to finishing treatments.

Durability

Moderately durable.

Treatability

Extremely difficult.

Moisture Movement

Small.

Density (Kg/m³)

560 (Density can vary by 20% or more).

Texture

Medium.

Use(s)

Joinery (interior and exterior) and decking.

Colour(s)

White/cream and light brown.

Environmental

Not listed in CITES. Believed available from well-managed sources.

Distribution

Widely distributed in Europe and northern Asia. It is found in the mountains of Spain and in the UK, especially in Scotland, at its westerly limits, in the north-west of Norway in a northerly direction, spreading east through northern Europe into Asia, and reaching the Verkhoyansk Range, while its extreme southerly point is in Spain, in the Sierra Nevada in Andalusia. It is found in the Maritime Alps in France and in the eastern Pyrenees, as well as in the Caucasus and Transylvanian Alps. It is the only true pine indigenous to the British Isles, being native to Scotland and just over the border; elsewhere in the UK, the forests are generally the result of planting.

The Tree

Generally 30m high with a diameter of about 1m but larger trees may be found on favourable sites.

The Timber

The sapwood is creamy-white to yellow in colour, narrow, especially in northern environments, becoming wider in the southern areas, and the heartwood is pale yellowish-brown to reddish-brown, resinous, and usually distinct from the sapwood. The growth rings are clearly marked by the denser late wood. The quality of the timber is affected by the conditions of growth, climate, soil, elevation, and so on, more so than most timbers because of its wide and varying distribution, and these factors affect the texture, density, size and number of knots. The weight of dried timber is about 510 kg/m³.

Drying

The timber dries rapidly and without undue degrade, but owing to its tendency to develop sap stain, it should either be anti-stain dipped or dried quickly after conversion.

Strength

For its weight, the timber is strong and moderately hard, although UK plantation-grown timber is generally slightly softer and weaker than that from other sources.

Working Qualities

Medium. In general, the timber works easily and well with both hand and machine tools, but ease of working and quality of finish is dependent upon the size, number of knots and degree of resin present. The wood is capable of a smooth, clean finish, can be glued, stained, varnished and painted satisfactorily and takes nails and screws well.

Durability

Slightly durable.

Treatability

Extremely difficult (easy for sapwood).

Moisture Movement

Medium.

Density (Kg/m³)

510.

Texture

Medium.

Use(s)

Joinery (interior and exterior), furniture, structural use, decking, mouldings, flooring and cladding.

Colour(s)

White/cream.

Environmental

Not listed in CITES. Believed available from well-managed sources.

Distribution

The natural habitat of larch is the mountainous areas ascending to great elevations, generally from the Bavarian to Swiss Alps, through western Poland and the Moravian Heights to the Carpathians. It has also been extensively planted elsewhere in Europe, including the UK where it was introduced early in the seventeenth century.

The Tree

Larch attains a height of 30m to 45m and a diameter of 1m or slightly more, and in favourable situations with a long, clean, cylindrical bole for two-thirds of its length. Essentially a natural tree of the mountains, it requires long, really cold winters for its best development; it is deciduous and appears to depend upon a long winter rest for the ripening of its wood. In the UK the winters are either short or mild, and neither provide ideal growth conditions. For this reason, English larch is generally inferior to that grown naturally in the mountains.

The Timber

The heartwood is pale reddish-brown to brick-red in colour, sharply defined from the narrow, lighter-coloured sapwood. It is a very resinous wood, with clearly marked annual rings, a straight grain, and a fine, uniform texture. It is rather heavy, weighing 590 kg/m³ when dried.

Drying

Dries fairly rapidly with an inclination to distort and for knots to split and loosen.

Strength

A hard tough timber, it is about 50 per cent harder than Scots pine and slightly stronger in bending and toughness; in other strength categories, it is about the same as Scots pine.

Working Qualities

Medium. Saws, machines and finishes fairly well, but loosened knots may be troublesome. The wood takes the usual finishing media quite well, but it tends to split in nailing.

Durability

Slightly durable/moderately durable.

Treatability

Extremely difficult/moderately easy (larch sapwood treatability may vary).

Moisture Movement

Small.

Density (Kg/m³)

550.

Texture

Fine.

Use(s)

Cladding, flooring, joinery (exterior) and structural use.

Colour(s)

Reddish brown (pale).

Environmental

Not listed in CITES. Believed available from well-managed sources.

Distribution

Although the natural distribution of this species is limited to a narrow belt on the southern Californian coast, it has been widely planted in South Africa and elsewhere in the southern hemisphere.

The Tree

In its natural habitat it usually grows to a height of 15m to 18m but in the southern hemisphere it tends to grow fast, reaching a height of 21 m to 25m in 25 to 30 years, usually with a diameter of 0.3m to 0.6m.

The Timber

The pale-coloured sapwood is commonly 75mm to 150mm wide, clearly distinct from the pinkish-brown heartwood. The growth rings, although mostly wide and distinct, show rather less contrast between early wood and late wood than those of Scots or Corsican pine. Consequently, the texture is relatively uniform. The average weight of the dried timber is about 480 kg/m³.

Drying

With care the timber dries with little degrade, however, where spiral grain is present, appreciable warping may occur.

Strength

Comparable to European softwoods.

Working Qualities

Good. The timber works reasonably well and clear material has little dulling effect on cutting edges. It planes to a smooth clean finish provided cutting edges are thin and sharp. Dull or thickened cutters tend to tear the wide zones of soft early wood and around knots. The timber can be glued satisfactorily.

Durability

Not durable.

Treatability

Difficult.

Moisture Movement

Medium.

Density (Kg/m³)

480.

Texture

Medium.

Use(s)

Furniture, structural use, sleepers and joinery (exterior).

Colour(s)

Pink/pale red (heartwood) and yellow-brown.