invented new way to set dock pilings

[Tom King]

 An older lady that lives not far away has a dock that her deceased husband built in the mid '80's.  All the wood is still fine, but there were some mistakes made in the structural design of the joist layout.  Long story short, it has several places with severe sagging.  She had a couple of dock companies come out and look.  Prices were 11k, and 19k to replace the exposed deck part, since the boat lifts part of it is fine.  All the decking boards need is a good pressure washing.

She is on fixed income, and could afford neither.  She called my Mother, now 103, and my Mother asked me if I could go look at it.  

Not that we need anything else to do, but I said I'd go over and check it out.  After loading up a truckload of stuff, and cutting a downed tree out of the way in her yard, we had the first new piling set where one should have been to start with.

  It involves a 2-ton chain hoist, a setup of 3' high scaffolding, and a 35 pound dumbbell.  Fortunately, there is sandstone about 4' down, so they don't need to be pounded so deep.  We took up a few decking boards at the lowest part of a dip.  I drilled a 1-3/4" hole through a 12' 4x6 in 5' of water. 3' high scaffolding is set up around the post, with a 2' wide stage on each side of the post.  Chain through hole holds top of chain hoist.  Chain hoist lifts sagging deck, and with all that weight hanging on the post, each tap of the 35 pound dumbbell drops it several inches,  Just hanging it on the chainhoist pulled it down the first couple of feet.  

Took about 2 hours to find, and load everything we needed, get to the dock after cutting the tree, and about an hour to set up, and set the first piling.  We had a small crowd watching, including some fishermen in Bass boats.  All were impressed.  

We're going back after 6 this evening to set the other needed post.  By then the Sun will be behind the trees.  Right now it's 93 with maximum humidity, and I don't work outside in those conditions.

Pictures coming.  Waiting on phone to send to computer.

 

[Chestnut]

This sounds interesting. Most docks around here are on wheels and get wheeled in and out every year. If you don't do that windblown ice will destroy them the first winter. This sounds like an awesome way to sink the posts for the dock. I'm interested in the pictures.

[Tom King]

Lost that picture, and too hot to go back to work this evening.  Still 92 degrees here at 6:30.  I'll take some more pictures in the morning.

The water level on the lake here is maintained with only a one foot variation.  It froze over in 1977, but never since.  There were a lot of docks heaved up then, but it's never happened since.  For those reasons, all docks are on pilings.

[Chestnut]

1 foot is a decent variation but I'm not sure what to expect. The lakes I'm used to don't vary much but they are spring fed woodland lakes tied to ground water.

 

[legenddc]

The lake on the other side of Tom is all floating docks and the levels vary a lot. I can't remember how much in height, but I remember having to move the dock a number of times when we were visiting my grandparents over the years.

[Tom King]

Yes, Kerr Lake, upstream of ours in the same Roanoke River varies as much as 30 feet, and they have some really elaborate floating docks there.  The lake downstream, Roanoke Rapids Lake, also varies in height, but not as much as Kerr Lake.  Both were built before our Lake Gaston.

Kerr Lake has a huge concrete dam, and is the one most used for flood control.  Ours has an earthen dam, and later designed high efficiency turbines that require a more constant head of water.  I think the real reason is the power company didn't want to go to the expense of building a concrete dam.  In any case, it works out good for us.

Our lake is 35 miles long, and covers 20,000 + acres, but the most upstream 10 miles is not much more than just like the river was before they built all the dams.  That tail end is the part you cross on I85.  Most people who have crossed the lake on 85 think they have seen the lake.

Took more pictures this morning.  Loading them now.

[Tom King]

Started by taking decking boards up at low spots.  Dropped 4x6 into water where we wanted it bolted to the dock structure.  Set up 3' high section of scaffolding around it, with 2' walkway on both sides of post.  Drilled 1-3/4" hole near top for short chain to hold top of 2 ton chain hoist.  Another 3/8" chain around the joist next to the post.

Using chain hoist, pull piling down, which also raises the sagging dock up-putting a lot of weight on the post.  That will pull it down 2 or 3 feet without touching the piling.

When it stops sinking the post, I get on top of the scaffolding, and pound it down with a 35 pound dumbbell.  I thought about making a heavier driver, and hanging it over the post under a 12' step ladder, but decided to try this first, and it worked fine.  There is sandstone down there not too far.  After several taps with the dumbbell, the chain hoist is used to put more pressure on the post.

Once the post gets too low to comfortably hit it while on the scaffolding, we disassemble the scaffolding, and BIg Mike drives it down the rest of the way until we hit the rock.

Then I drill a 5/8" hole through post, and joist, and install 5/8" galvanized bolt.  Top is cut with small chainsaw.

The builder had cantilevered a 2/8 joist out 4 feet, and used that point to hold three other supporting joists at the intersection. Those spots had sagged about 3" each, and broken the 1/2" bolts in the posts down the center that were supporting that cantilever point.

It was built in 1987, by the owner the only year the lake was lowered.  It's amazing it lasted as long as it did, but the old style treated wood is still  hard as a rock.

We had the last post set by 10:45 this morning, but by then that 35 pound dumbbell, the heat, and humidity, said we were done for the day.  Tomorrow, we'll replace the decking boards we broke getting them up, because of the old rusted decking screws (from back when decking screws were not much more than galvanized sheetrock screws).  

[Coop]

That widow lady owes you guys a couple of home cooked meals. Glad to hear your mom is still telling you what to do! Wish mine was.  103 yo! That’s amazing!

[Chestnut]

Yep pictures show exactly what i pictured. Genius. Nothing beats using the weight and structure at hand to help you do the work.

[Bankstick]

Very creative! Now you have a part-time job on the lake.