Brief description

A road surfacing method using rectangular wooden blocks, usually set with the grain vertical (end-grain), placed on a solid foundation. It was popular in 19th-century cities for being quieter and smoother than cobblestones.

Use / Function

• Primary use: Urban street paving to reduce noise from horses’ hooves and iron carriage wheels.
• Secondary uses: Interior industrial flooring (absorbs impact), bridge decks (lighter than stone).
• Scale: City streets, bridges, factory floors.

Operating principle

• Shock Absorption: Wood is softer than stone, cushioning impacts and dampening sound.
• End-Grain Durability: Placing wood blocks with the grain vertical makes them much more resistant to wear and splitting than placing them flat.
• Traction: Provides good grip when dry, though can be slippery when wet.

How to create it

1. Foundation: Prepare a stable base. Historically, this was often a layer of planks or, better, a concrete slab.
2. Preparation: Cut wood into uniform rectangular blocks (e.g., 15x8x15 cm). Hardwoods or resinous softwoods are best.
3. Treatment: Dip blocks in boiling tar or creosote to preserve them and prevent rot.
4. Laying: Place blocks in rows on the foundation with the end grain facing up. Leave small gaps (2-3 mm) between rows for expansion.
5. Jointing: Pour hot tar or bitumen into the gaps and cover with fine gravel or sand to seal the surface and provide grip.

Materials needed

• Essential:
  • Wood: Blocks of pine, oak, or cedar.
  • Tar / Bitumen: Preservative and sealant.
• Foundation:
  • Concrete or Gravel base.
• Tools:
  • Saw: For cutting blocks.
  • Hammer: For setting blocks.

Variants and improvements

• Nicholson Pavement: An early US version using a plank foundation and tar.
• Creosoted Blocks: Pressure-treated wood for longer life against rot.
• Interior Block Paving: Used in factories to protect dropped tools and reduce worker fatigue.

Limits and risks

• Slippery when wet: Became notoriously slippery for horses in rain.
• Expansion: Wood swells when wet; if not spaced correctly, the road surface could buckle or push over curbstones.
• Sanitation: Wood is porous and absorbs urine and waste from animals, leading to bad smells in warm weather.
• Rot: Even with tar, wood eventually decays.

Related inventions

• Road: General concept.
• Cobblestone Path: The competitor it replaced in some wealthy districts.
• Macadam: Alternative paving method.