Timber pilings

Timber pile construction in the aquatic and marine environment has a long history in Europe dating as far back as the bronze and Stone Age in Switzerland.

[1] During severe droughts in Switzerland in the mid-nineteenth century, lake areas that had been previously inundated with water were exposed to reveal ancient archaeological remains of various types of timber piling support assemblies that served as foundations for both individual houses and community buildings.

The early Venetian constructors used building techniques that included using impermeable stone supported by wooden rafts and timber piles.

[2] The timber piles did not rot because they were set into the mud at the bottom of the lagoon which prevented oxygen and harmful microbes from reaching them.

In the 18th and 19th centuries the study of wood preservation was revived due to the deterioration of the timber pile dikes that protected Holland as well as the high level of decay and marine borer activity in English Navy ships.

[5] There are three groups of marine borers in West Coast waters including gribbles, shipworms, and pholads, and each differs in the type of damage it causes.

[9] One beetle, the wharf borer (Nacedes melanura), can attack untreated or damaged treated hardwoods and conifers with high moisture contents by tunneling extensively and leaving behind dark brown fecal matter that further degrades the wood.

Apply a liquid preservative to cutoff tops of piles and timbers by flooding them with hot creosote (150 to 200 °F), pentachlorophenol in diesel oil, or copper naphthenate in mineral spirits.

[11] A solid preservative, such as Fluor-Chrome-Arsenic-Phenol (FCAP), can be applied dry or as a paste where hawsers rip off caps and expose wood to moisture and decay organisms.

[11] Creosote effectively prevents attack by marine borers in coastal waters north of San Francisco and inorganic salts [Chromated Copper Arsenate (CCA) or Ammoniacal Copper Arsenate (ACA) are recommended south of San Francisco because of the likelihood of attack by the wood borer that is predominantly located in warmer waters.

[14] Where damage is more severe, forms made of metal, wood, concrete, woven nylon, or pitch-impregnated fiber are attached to the pile as far down as 2 feet below the mudline.

[14] In order to effectively preserve and maintain timber piles, regular inspection is required to detect deteriorating structures before replacement is necessary.