Thanks for all the comments and thoughts. Will share with the engineers we are using.

We had not considered plastic. How does that hold up to ice? This is all freshwater here.

Sheet piling
 

If you are going to be putting in 30 foot sheets I would put in Z panels. The 7 gauge would not be good for 30 foot sheets. I am a contract that does this type of work if you have any pictures or other information you want to send over i can give you a estimate on the job. My email is [email protected] and my website address is www.bandrconstr.com if you want to look at some of our work. Thanks Ross

Hi B&R

This post is a year old. The work is all done. Thanks for your input though.

Fred

so did you go with the plastic?

No, we went with a 5 ga piling, 30 feet long. A new tie-back system was also installed.

The top of sea wall is about 6 feet above the water. The water at the wall is about 6 feet deep. There are bolders piled up to about a foot from the surface now, and taper down to about 4 feet below the surface 10 feet out.

About the ice factor
 

I just saw this post and had to reply because I read the ice post on page one of this thread and it was an issue for me as well, plastic does not cut it for high pressure ice!

Up here in Michigan ice is a huge factor in seawall construction. I ended up going with 100% steel seawalls after my vinyl wall was trashed the first winter. The steel seawall has held up great for 2 years and I have been nothing but happy, I had a custom dock built for our ski boats as well. Not as cool as the boats some of you gentlemen are rocking, but great for inland lakes :).

The guy I used worked for Seaside Seawalls, his name was Aaron if I remember properly. He was extremely knowledgeable and I asked him many questions before I decided to have my wall built. Even though its a ways away I would recommend picking his brain even if you are not going to use him (does that make me bad? ;) ). Search Michigan seawalls and you should find lots of information about it and his site. Hope this helps someone in the future

seawall construction requires that the sheets be driven
 

We realize that proper seawall construction requires that the sheets be driven, not washed down. We own vibratory hammers capable of installing wooden or vinyl steel sheet piling in residential construction. Our dead man/tieback systems can be installed with vibratory equipment so as not to disturb existing ground or structures built close to the water.

between 500 & 1000/ft I believe

Bill is correct according to quote I got.
IN ONTARIO ...BY BARGE

105 ft shoreline
30 ft sheets
tie backs included
clear stone backfill ( sheets have 6ft of exposure above lake level)

$ 65000.00

Steel piles are able to provide a cost effective solution to a wide range of foundation applications. Manufactured in continental Europe steel piling is especially suitable for building structures in a sustainable and cost effective manner. Major manufacturers form steel sheet piling in electric arc furnaces, utilising a blend of scrap products from a variety of sources. The chemical content of steel piles is strictly controlled in order to produce material of acceptable section modulus to satisfy all current construction and design codes, particularly with regard to the relevant Euro Codes, and CE certifications.