Merpauh Wood: Versatile and Durable for Construction and Joinery

Projects

 

Introduction

Merpauh is the Standard Malaysian Name for the wood derived from various species of the Swintonia genus, belonging to the Anacardiaceae family. Locally, it is known by several names, including Merpauh in Peninsular Malaysia, Rengas in Sabah, Pitoh in Sarawak, and Periang in different regions. Some prominent species include Swintonia floribunda var. penangiana, S. schwenkii, and S. spicifera.

 

This wood is typically characterized by its light brown sapwood, with a grey or pink tinge, and its heartwood, which has a light grey-brown hue with a slight pink tinge. In some trees, corewood develops, streaked with orange and red lines, adding aesthetic value. Merpauh is also known by different names internationally, such as Kereta and Maban in Indonesia, Muom in Vietnam, and Kaluis in the Philippines.

 

Density

Merpauh is classified as a Medium Hardwood, with a density ranging from 640 to 880 kg/m³ when air-dried, making it suitable for a variety of construction and furniture applications.

 

Natural Durability

In durability tests carried out by the Forest Research Institute Malaysia (FRIM), untreated Merpauh wood exhibited an average service life of only 1.5 years, classifying it as non-durable. It is highly susceptible to insect and fungal attacks, including staining fungi, which can discolor both sapwood and heartwood.

 

Preservative Treatment

The wood’s treatability varies among species, ranging from very easy to moderately difficult. Proper treatment can extend its lifespan and usability in more demanding environments.

 

Texture

Merpauh wood has a moderately coarse but even texture, often with interlocked grain patterns.

 

Strength Properties

Merpauh is categorized under Strength Group B (Engku, 1988b) or SG 4 (MS 544: Part 2: 2001), making it relatively strong and suitable for construction.

 

Strength Properties of Merpauh (MPa)

| *Species*                      | *Moisture Condition* | *Modulus of Elasticity* | *Modulus of Rupture* | *Compression Parallel to Grain* | *Compression Perpendicular to Grain* | *Shear Strength* |

|———————————-|————————|—————————|————————|————————————-|—————————————|——————–|

| S. floribunda var. penangiana   | Green                  | 14,700                    | 77.0                   | 40.5                                | 4.48                                  | 10.9               |

|                                  | Air-dry                | 16,300                    | 103.0                  | 51.4                                | 7.24                                  | 12.6               |

| S. schwenkii                    | Green                  | 14,200                    | 76.0                   | 37.7                                | 4.34                                  | 10.4               |

|                                  | Air-dry                | 15,700                    | 97.0                   | 47.7                                | 6.41                                  | 13.4               |

| S. spicifera                    | Green                  | 16,800                    | 80.0                   | 39.7                                | –                                     | 13.2               |

|                                  | Air-dry                | 18,100                    | 108.0                  | 56.6                                | –                                     | 13.3               |

 

Machining Properties

Merpauh wood is challenging to saw and cross-cut due to its toughness. However, it is easier to plane, and the resulting surface is typically smooth.

 

| *Species*                      | *Condition* | *Resawing*   | *Cross Cutting* | *Ease of Planing* | *Quality of Finish* | *Ease of Boring* | *Turning Ease* | *Turning Finish* |

|———————————-|—————|—————-|——————-|———————|———————-|——————-|——————|——————-|

| S. floribunda var. penangiana   | Green         | Difficult       | Difficult          | Easy                | Smooth               | Difficult          | –                | –                 |

|                                  | Air-dry       | Very Difficult  | Very Difficult     | Easy                | Smooth               | Difficult          | Slightly Rough    | Slightly Rough    |

| S. schwenkii                    | Green         | Moderately Easy | Moderately Easy    | Easy                | Smooth               | Difficult          | –                | –                 |

|                                  | Air-dry       | Difficult       | Very Difficult     | Easy                | Smooth               | Very Difficult     | Rough             | Difficult         |

| S. spicifera                    | Green         | Very Difficult  | Very Difficult     | Easy                | Smooth               | Very Difficult     | –                | –                 |

|                                  | Air-dry       | Very Difficult  | Very Difficult     | Easy                | Smooth               | Slightly Difficult | Rough             | Rough             |

 

Nailing Property

The nailing performance of Merpauh wood ranges from good to poor depending on the species.

Air Drying

Merpauh wood air-dries relatively fast, with slight defects like cupping, bowing, twisting, and occasional insect attacks. The drying time for 13 mm thick boards is approximately 2 to 2.5 months, while 38 mm thick boards require around 3.5 to 4.5 months.

Kiln-Drying

Kiln Schedule C is recommended for Merpauh wood. Proper kiln-drying techniques can help minimize defects during the drying process.

 

Shrinkage

Merpauh exhibits low to moderate shrinkage during the drying process.

 

| *Species*                      | *Radial Shrinkage (%)* | *Tangential Shrinkage (%)* |

|———————————-|————————–|——————————|

| S. floribunda var. penangiana   | 0.8                      | 1.5                          |

| S. schwenkii                    | 1.4                      | 2.0                          |

| S. spicifera                    | 0.9                      | 1.8                          |

 

Defects

Merpauh logs left exposed are prone to insect attacks and fungal infections, especially in the sapwood, which can rot and stain quickly. Heartwood may also suffer from staining but is generally more durable.

 

Usage

Merpauh wood is ideal for light to medium construction projects under cover. Due to its attractive streaked corewood, it is often used in high-class joinery and furniture. Other common applications include interior finishing, panelling, mouldings, partitioning, flooring, and door and window frames. It is also suitable for telegraphic and power transmission posts, cross arms, and railway sleepers.