What special features does Meranti have as a material?
Abbreviation DIN EN 13556: SHDR
Botanical name: Shorea, subgenus rubroshorea, family Dipterocarpaceae
Distribution: South East Asia, mainly Malaysia and Indonesia
Trade names: Red meranti (MY), red seraya (MY-SAB), meranti merah (ID), red lauan (PH), as well as numerous local names in the different growing regions
The commercial assortment Red Meranti contains a large part of the light to dark red-brown woods of the numerous Asian Shorea species. Within this group there are clear differences in colour as well as biological and technical properties, which initially led to a practice-related subdivision according to colour and density into Dark Red Meranti and Light Red Meranti, which already provided an indication of the different possible uses.
However, due to the over-use of the Dark Red Meranti range, which is preferred in Europe, combined with the switch from round and sawn timber exports to semi-finished products (mainly glued scantlings for windows and doors), the colour and bulk density profile has shifted towards lighter and lighter wood, so that the differentiation into ‘dark’ and ‘light’ red meranti, as laid down in the Malaysian Grading Rules of 1984, is no longer practicable. Investigations on window scantlings imported from Malaysia and Indonesia (Gütegemeinschaft 1998) have shown a range of gross density (u = 12 %) of 0.27-0.58 g/cm³, with the vast majority of the wood in the range between 0.38 and 0.47 g/cm³.
The following description therefore only considers the assortment imported today, which is commonly marketed as Red Meranti.
Sapwood light grey to pale pink, heartwood pale pinkish brown to medium reddish brown. Resin channels present in all species, on the cross section in mostly ring-shaped arrangement, partly also in short tangential bands. On the surface, the channels can form conspicuous, chalky flakes or stripes due to crystallized, white resin. Growth zones are usually not visible. The dry wood has no specific smell.
Structurally predominantly homogeneous wood of coarse texture, but highly variable in density and colour; wood appearance simple; with more or less distinct glossy stripes due to interlocked twisting growth on radial surfaces.
As with all resin-bearing woods of the Dipterocarpaceae family, Red Meranti may also have dark resin ducts which tend to bleed out under the influence of heat for a long time. Small pin holes of fresh wood insects are more common; they do not impair the mechanical strength, but should be filled in on visible surfaces. Short brittle (brittleheart) or woolly wood in the inner core is possible with very light qualities and must be sorted out before processing.
The surface treatment does not cause any difficulties, the wood can be stained and glazed well; pore fillers are required before painting.
The predominantly light-coloured and rather light woods are easy to work, peel and knife with all hand and machine tools. The wood is easy to nail, screw and glue.
The shrinkage values are in the medium range and result in medium to good stamina. Technical drying is rapid, but requires careful control to reduce deformation and cracking.
Natural durability (DIN-EN 350-2)
The grading of the heartwood in durability class 3-4 (moderate to low durability) applies to the gross density range of 0.49-0.55 g/cm³. According to the guidelines of the RAL quality mark (Gütegemeinschaft 2007), chemical wood protection before coating is generally recommended for wood in the raw density range of 0.40-0.48 g/cm³ (conditionally approved for window construction).
Red meranti below 0.40 g/cm³ does not meet the minimum requirements of the RAL Quality Mark with regard to the gross density and the low natural durability that can be approximately derived from it; it is not approved for window construction.
Areas of application
Red Meranti is now almost exclusively available on the European market in the form of semi-finished or finished products, mainly as glued raw scantlings for frame construction (windows and doors) and as plywood for furniture production. Occasional sawn timber imports of high quality wood (dark red meranti) are massively used in frame construction, as construction timber for medium-duty use in interior and exterior construction as well as for stairs and furniture components. Other applications such as wall and ceiling panelling, blind veneers and packaging are of secondary importance.
The bulk density is the most important criterion for the use of Red Meranti, as it has a decisive influence on both the technical and biological properties. According to the standards set by the Gütegemeinschaft Holzfenster und -haustüren e. V. (1998), for example, a decrease in bulk density from 0.45 g/cm³ to 0.35 g/cm³ reduces the bending strength by 12 %, the bending modulus of elasticity by 20 %, the screw and nail pull-out strength by 18 % and 27 % respectively, and the Brinell hardness (⊥) by 33 %.
Fungal resistance also decreases with the density, so that wood with a density below 0.49 g/cm³ must be assigned to durability class 4-5 (Gütegemeinschaft 2007).
Meranti, red – Technical properties
Weight fresh600-800 kg/m³
Bulk density air-dry (12-15% u)0.30-0.58 g/cm³
Compressive strength u12-1521-50 N/mm²
Flexural strength u12-1532-80 N/mm²
Modulus of elasticity (bending) u12-156 550-11 000 N/mm²
Hardness (JANKA) ⊥, converted0.5-2.8 kN
Hardness (BRINELL) ⊥ to fiber u12-158-14 N/mm²
Differential shrinkage (radial)≈ 0,15 % 0,15
Differential shrinkage (tangential)≈ 0.28 % 0.28
pH-Wert≈ 4.7 (weakly acidic)
Natural durability (DIN-EN 350-2)3-4 (-5)