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Dock Rebuild (again) - Hog Slat v. Flow-Through poly decking

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Dock Rebuild (again) - Hog Slat v. Flow-Through poly decking

Old 09-18-2019, 06:27 PM
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Default Dock Rebuild (again) - Hog Slat v. Flow-Through poly decking

So, like many on Ocracoke, I'm dealing with lots of repairs to the house and dock courtesy of Dorian. This will be my third dock rebuild and I'm looking for ideas on upgrading materials. As you can see in the before/after image below, the dock is completely exposed facing W/NW. The decking material was Trex and held up incredibly well over 12 years; however, the stringers just can't take the beating from the wave action. Even using joist hangers and carriage bolts, the 2x6s just rip up and break off in large paletts with the planking still perfectly attached. I'm currently thinking about upgrading to 4x6s and using either hog slat or commercial plastic flow-through decking like Titan Open X. I'm also debating lowering the dock to get it under the destructive storm surge and wave action. If you are wondering what this area looks like during a storm, below is a video shot by my neighbor during Hurricane Matthew. You can see the intense wave energy hitting the dock at about the 2:40 mark. I know nature always wins, but I feel like I could make some changes to improve my chances. One of the reasons I'm considering the flow-through decking is the easy removal of sections prior to a storm. But hog slat is an always on solution, which is appealing as well. What to do...thoughts?



Old 09-18-2019, 06:40 PM
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Lowering the decking will only expedite its exodus as the wave energy translates through the entire depth
Old 09-18-2019, 06:50 PM
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Instead of lowering the pier, how about raising it 3-4 feet? Then a step down at the end.
Old 09-18-2019, 06:51 PM
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If you build low, build low. My neighbor built a low hog slat pier years ago, with actual hog slats. It finally got old and needed to be replaced He just had it replaced by "professionals" and this time the pier was about a foot higher. Three out of four slats cracked on the T and one of them is trashed. 20 years ago when I bought our house on the Pamlico River (four miles wide and on he south side) the only piers that survived Dennis and Floyd were built high...so I built mine high. I have had to re-top it three times. Poles were driven, not washed in and so far so good. Also, another option is to remove every other board as the wave action is the kicker but that would be a pain. Good luck with your decision.
Old 09-18-2019, 06:53 PM
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What if you could hinge sections to one side, so that when a storm approaches, unlatch the opposite side and lift section vertical against piling and latch it to the pilings. Using the flow thru decking would be good, but more to all but eliminate the "sail" effect from the winds if coming from a cross direction. Wave action or storm surge would have very little to exert force on.
Old 09-19-2019, 07:07 AM
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This might be something worth looking into. We just wrapped up a project for a pier where they used a center section of grate.





Old 09-19-2019, 07:12 AM
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They use that grate material in the keys in areas with sea grass to let light through.
Old 09-19-2019, 10:04 AM
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build the pier in 4 ft sections and take them off if there's a hurricane coming.. stack up and tie to a tree and reinstall after the storm.. been doing this for 30 years
Old 09-19-2019, 10:59 AM
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My vote is go low. After Katrina on our stretch of Mobile Bay the only pier that made it was set about 1' above normal high tide. By the time it got rough and all the others were getting battered by floating trees this one was way underwater. No damage at all.
Old 09-19-2019, 11:18 AM
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I’m in the same boat...

Before and after.
Old 09-19-2019, 05:22 PM
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Our 15 yo dock is higher than the neighbors. Its only about two feet higher. We lost a few boards last year. All the docks at the lower height were history.
Note, this is on a tidal creek off of Core Sound. It appeared that the waves popped the decking UP as the tide rose. I can see how a grate would mitigate this some.

I know that some other folks will have their decking numberered 1 thru 3. They are screwed down. Removed numbers 2 and 3 prior to hurricanes. Waves that lift the dock were able to go thru holes. Wont work for everything.

Each situation requires a diffrenent approach.

Last thing. If i had known our dock was gong to last this long would have used a synthetic decking. But our dock is not that long ($).
Old 09-19-2019, 05:51 PM
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My neighbor spent a kings ransom on Hog Slat deck for a small pier on Bogue Sound. His builder did everything right and it was more like a fort than a pier. Along came Florence and her 4 ft waves and the hog slat sections got tossed from the force of waves from underneath. Concrete is pretty buoyant in salt water negating a large portion of the weight. Great for resisting wind but waves from below - not so much. If I were you I’d get FRP grating (Fibergrate) and use the stainless wing washers and screw it down every couple inches. There’s a very good reason that the lower levels of every single oil production platform in the world have fiberglass grating for their walkways. The waves just flow right up through it and it never rusts. The Fibergrate has UV inhibitors in the resin to protect it from sun. You can save $ by getting the “pultruded” type versus molded.
Old 09-20-2019, 04:54 AM
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Thank you for the replies (and photos). I will continue to research, especially these grate materials. Will report back and update this thread when I move forward.
Old 09-20-2019, 05:23 AM
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Originally Posted by BigRockCabo View Post
My neighbor spent a kings ransom on Hog Slat deck for a small pier on Bogue Sound. His builder did everything right and it was more like a fort than a pier. Along came Florence and her 4 ft waves and the hog slat sections got tossed from the force of waves from underneath. Concrete is pretty buoyant in salt water negating a large portion of the weight. Great for resisting wind but waves from below - not so much. If I were you I’d get FRP grating (Fibergrate) and use the stainless wing washers and screw it down every couple inches. There’s a very good reason that the lower levels of every single oil production platform in the world have fiberglass grating for their walkways. The waves just flow right up through it and it never rusts. The Fibergrate has UV inhibitors in the resin to protect it from sun. You can save $ by getting the “pultruded” type versus molded.
I have a friend with a brand new dock that in Florence had a similar issue. The problem was the panels were not bolted down and the way the builder designed the girders and frames did not allow for bolting through the slat openings. Panels must be bolted down.

Build it high. Get the lifts high enough to keep the motors dry. Pilings must be vibrated down, not washed in, to sufficient depth to have firm footing and holding power to prevent lift. Construction is simple- each pair of pilings on 8' centers has a 4x10 on each side through bolted with two 1/2" timber bolts per piling. A 4x6 is bolted on each side as edging. The slats are bolted down in four corners through the 4x10 with 1/2" timber bolts. It you want to put cross bracing you can.

Look at Bobby Cahoon's web page. Bobby knows how to build a dock that will last- Bobby Cahoon Construction, Inc. - Welcome






Above is simple construction that works. Some of the dock builders will design a framing system that the panel sits in for the aesthetics of not having the timber bolt heads on top...they also make a pile on labor and material costs. It's not needed and the panel gets displaced with lift in a storm. Above is simple and strong. The panel is designed to function with that free span.

Below is the cost sheet for a dock I built in 2010. It's 300' to the platform. This was during the recession after the real estate crash. Material inventory was extremely heavy. Builders were looking cash work to keep their crews together and pay down credit. It was a great time to build a dock and buy a boat. Today is totally different. Harvey, Mathew, Florence and Dorian have everything at a 2x to 3x premium. I put a new roof on for $100 a square labor in 2011 after Irene. This week I replaced one side due to a leaking skylight at $200 a square labor.



Last edited by Rick S; 09-20-2019 at 06:21 AM.
Old 09-20-2019, 01:33 PM
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There’s not a right answer here, so I won’t argue one way of the other re. hog slat or flow-thru poly.

With hog slat if you go that way, the advice to have to bolted down is key. Without that all you’re asking for is ridiculously heavy sections tossed around damaging other stuff and making cleanup a PITA.

I rebuilt after Florence with Sure Step poly. Prior to Florence I had two levels of dock—an older walkway that was lower and a newer platform section at the end that was higher. Both wood decking. The walkway section (abt 275’) was destroyed, because it was old but also because all the docks upwind of me disintegrated and the loose bits tore mine to pieces.

The outer higher section survived structurally but lost all its top boards.

After a rebuild with everything at the higher level, it all survived Dorian unscathed. I think that was partly the Sure-Step—it is 36% open space, so the hydraulic pressure from below is significant lower. It was also partly that the storm was not as bad—Flo was sort of a worst case for where I am, with 36 hrs of NE winds from 40-80 mph in the widest section of Bogue Sound.

And of course it it was also that Flo cleaned out a lot of sketchy docks so the debris wasn’t quite as bad.

But the Sound was definitely over the dock as it was in my yard a decent ways, and the Sure Step worked well. For now I am pleased, but ask again in 10 years and my answer might be different. I might have gone hog slat if my contractor did them. But I wasn’t willing to wait 2 years to have it rebuilt...by pure chance I was the next on the list to replace the lower older walkway with my contractor when Florence hit, so I was rebuilt pretty quickly.

If you go with the Sure Step, your contractor has to be very precise with piling alignment. There are 5 stringers in this kind of dock, and the holes for screws are pre-bored. So they’ve gotta be real straight especially over a long run so that the screws hit the meat of the stringers. Happy to answer any more questions.


Last edited by jdc; 09-20-2019 at 01:38 PM.
Old 09-20-2019, 01:46 PM
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For me thats a good application for the poly. I don’t know but I would think that as the waves and water rose you’d be under water pretty quickly in the Lake. So allowing the water up and thru more easily would be better. You don’t have a ton of fetch like the Pamlico where the hog slats are so popular. And with the length of your dock the cost increase wouldn’t be massive.

Originally Posted by Tarbaby View Post
I’m in the same boat...

Before and after.
Old 09-21-2019, 02:37 AM
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That sure step material gets my vote. Saw one in sea island ga. Finding someone in ocock to build it is another story. I have seen all the other options wash away in Washington. Good luck joe
Old 09-23-2019, 07:15 AM
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Originally Posted by Rick S View Post
I have a friend with a brand new dock that in Florence had a similar issue. The problem was the panels were not bolted down and the way the builder designed the girders and frames did not allow for bolting through the slat openings. Panels must be bolted down.

Build it high. Get the lifts high enough to keep the motors dry. Pilings must be vibrated down, not washed in, to sufficient depth to have firm footing and holding power to prevent lift. Construction is simple- each pair of pilings on 8' centers has a 4x10 on each side through bolted with two 1/2" timber bolts per piling. A 4x6 is bolted on each side as edging. The slats are bolted down in four corners through the 4x10 with 1/2" timber bolts. It you want to put cross bracing you can.

Look at Bobby Cahoon's web page. Bobby knows how to build a dock that will last- Bobby Cahoon Construction, Inc. - Welcome






Above is simple construction that works. Some of the dock builders will design a framing system that the panel sits in for the aesthetics of not having the timber bolt heads on top...they also make a pile on labor and material costs. It's not needed and the panel gets displaced with lift in a storm. Above is simple and strong. The panel is designed to function with that free span.

Below is the cost sheet for a dock I built in 2010. It's 300' to the platform. This was during the recession after the real estate crash. Material inventory was extremely heavy. Builders were looking cash work to keep their crews together and pay down credit. It was a great time to build a dock and buy a boat. Today is totally different. Harvey, Mathew, Florence and Dorian have everything at a 2x to 3x premium. I put a new roof on for $100 a square labor in 2011 after Irene. This week I replaced one side due to a leaking skylight at $200 a square labor.


That is the way I build them in Charleston. I am currently looking into using the poly flow through decking as a regular upgrade over traditional wood decking. People in Charleston like wood- they still want wood bulkheads instead of vinyl or FRP. The bad part is many areas around Charleston have serious problems with the wood boring worms. Our average dock length is about 300' and we build up to 1000'
Old 09-23-2019, 09:32 AM
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Anyone have recent pricing on the hog slats only? 4X8'?
Old 09-24-2019, 08:03 AM
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Originally Posted by 1blueheron View Post
Anyone have recent pricing on the hog slats only? 4X8'?
I think @ 150.00.

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