Softwod for jetties 2

[Smoulder]

Timber jetties I've worked on were all hardwood. What about softwoods in tidal water especially plantation pine? All good as long as double treated with CCA and creosote? Code allows untreated heartwood less than 20% of cross section. Should I go further and say no untreated heartwood? I think sawn pine should be available that's all sapwood so all treatable but not sure how much sorting snd selection would be needed and whether it's not practical even if theoretical possibility. I think this must be common overseas even if not here in Australia.

 

[phamENG]

Pine has been used in the Southeast US for a very long time. That's not to say it's a great material for the purpose, but it works. Most commercial and industrial applications have moved away from it as it doesn't have the longevity of steel and concrete, but residential and light duty piers are almost exclusively pine in my area. Further down the coast where hurricanes tend to be a bit stronger is where concrete takes over for everything but small residential piers.

CCA and Creosote are the most common treatments for pine used in coastal waters around here. Specifications are often based on organisms that are local to the project - on the US Atlantic coast, we have three separate treatment specifications based on whether your northern, central, or southern because the threats vary slightly with changes in water temperature.

Protecting wood in the tidal zone is a good idea, too, if you need added longevity. Pile jackets that prevent organisms from boring into the wood in the first place will go a long way. They are commonly used to restore damaged piles, but some people put them on from the start. The issue is that once it's on, you can't inspect the wood. So it's a trade off.

 

[Smoulder]

@Phameng thanks for passing that along. Really useful to know it's not rare to use pine. Are sawn boards ever used in and below tide level like for xbracing? Or only round piles down there?

 

[LittleInch]

Looking up CCA, it seems to be permitted for the structural components, but may not be for where people can touch it so not so good for deck boards or where people can use it with their hands.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[phamENG]

Smoulder - yes, sawn board are used in that way as long as they are appropriately treated. But again - different species and treatments will respond differently in different regions where the threats to the wood are slightly different. Be sure to check on local conditions - if nobody is using it, there may be a good reason that we don't have to deal with here.

 

[Smoulder]

@Phameng thanks again. I'll look some more into local issues but reckon it's just that australia had plenty of hardwood when timber wharves were in fashion. Including turpentine which is naturally resistant in seawater. More than other species but still breaks down over time. Also the old growth was better than newer stuff which is cut fown younger. We have southern treatment (cca or creosote) and northern (cca and creosote) similar to your three zones.

@Littleinch yep, good point. We can't use cca for the railings. Deck boards are a maybe but we usually avoid there too as not worth the risk. These are out of the water so less treatment gets the job done.

 

[hokie66]

Composite decking deserves consideration.

 

[Smoulder]

@Hokie66 Do you have good experience with composite? Better yet some sort of independent study on durability? We're hesitant to make the leap. Seen some really bad stuff that didn't last in the sun and water. Problem is it's resold from china by laypeople with no tech support. The better stuff in terms of tech support is frp grating which looks nothing like timber. We're happy to use that but some people want the board look. We can't put our name to that because we haven't found anything to convince us.