A batten is a thin strip of solid material, typically made from wood

Wood

Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

, plastic

Plastic

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

 or metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

. Battens are used in building construction and various other fields as both structural and purely cosmetic elements. In the steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 industry, battens may also be referred to as "top hats", in reference to the profile of the metal.

Battens are used in building construction in various ways:

• Roofing battens are used to provide the fixing point for roofing sheet or roof tiles. The orientation and spacing of the battens depend on the type of roof. Battens may be oriented at right angles to the truss
  Truss
  In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...
  
  es or rafter
  Rafter
  A rafter is one of a series of sloped structural members , that extend from the ridge or hip to the downslope perimeter or eave, designed to support the roof deck and its associated loads.-Design:...
  
  s of a roof like purlin
  Purlin
  In architecture or structural engineering or building, a purlin is a horizontal structural member in a roof. Purlins support the loads from the roof deck or sheathing and are supported by the principal rafters and/or the building walls, steel beams etc...
  
  s. They may be parallel to the slope of the roof, as on a batten-seam roof, where the battens cover seams in the roofing material and are themselves covered by metal caps. Some roofs may use a grid of battens in both directions, known as a counter-batten system.
• Batten trim or batten molding is a thin strip of trim
  Molding (decorative)
  Molding or moulding is a strip of material with various profiles used to cover transitions between surfaces or for decoration. It is traditionally made from solid milled wood or plaster but may be made from plastic or reformed wood...
  
  , typically with a rectangular cross-section, used to cover seams between panels of exterior siding or interior paneling.
• Board-and-batten siding
  Siding
  Siding is the outer covering or cladding of a house meant to shed water and protect from the effects of weather. On a building that uses siding, it may act as a key element in the aesthetic beauty of the structure and directly influence its property value....
  
   is an exterior treatment of vertical boards with battens covering the seams.
• Battens are used for solid wall insulation. Regularly spaced battens are fitted to the wall, the spaces between them filled with insulation, and plasterboard or drywall screwed to the battens. This method is no longer the most popular, as rigid insulation sheets gives better insulation (with battens bridging the insulation) and take less time to fit.

Other uses

• In sailing
  Sailing
  Sailing is the propulsion of a vehicle and the control of its movement with large foils called sails. By changing the rigging, rudder, and sometimes the keel or centre board, a sailor manages the force of the wind on the sails in order to move the boat relative to its surrounding medium and...
  
  , battens are long, thin strips (usually fiberglass
  Fiberglass
  Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
  
   or some similar material nowadays, but historically wooden) used to support the roach of a sail
  Sail
  A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
  
  . They are also used on tall ships to form the ladders up the shrouds in a fashion similar to ratlines
  Ratlines
  Ratlines, pronounced "rattlin's", are lengths of thin line tied between the shrouds of a sailing ship to form a ladder. Found on all square rigged ships, whose crews must go aloft to stow the square sails, they also appear on larger fore-and-aft rigged vessels to aid in repairs aloft or conduct a...
  
  . They are also used to help secure tarpaulin
  Tarpaulin
  A tarpaulin, colloquially tarp, is a large sheet of strong, flexible, water-resistant or waterproof material, often cloth such as canvas or polyester coated with urethane, or made of plastics such as polyethylene. In some places such as Australia, and in military slang, a tarp may be known as a...
  
  s over hatches, thus giving rise to the common phrase "batten down the hatches!", meaning to secure the hatches against an approaching storm. Used by analogy in non-sailing contexts, it means to prepare to weather a coming storm, whether that storm is metaphorical or real.
• In cabinetry, battens may be used to strengthen panels made up of multiple boards, as in a batten door, or to cover joins.