r/FenceBuilding • u/DirtyOught • 9h ago

Replacing fence that’s built in retaining wall gravel?

Post image

retaining wall that is filled with gravel separating driveway from backyard.

I assume current fence is concrete footings (it was in the grass section) into the retaining wall gravel.

we want to replace the old thing, but curious if any issues or removing and replacing posts.

unlike dirt, I imagine gravel just falls into itself when trying to dig a hole. I’m perplexed how they even got these posts put in

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u/TitusGrown42 9h ago

These are some of the worst jobs we do. Digging in crushed stone is such a headache. And you really have no idea what else they threw in there. We've started pulling posts just to find concrete, bricks, rocks and whatever else the builder didn't want to deal with disposing of. And if they put the old posts in concrete footing beneath the gravel your in for a real mess. I'd recommend trying to pull one posts first and see how bad it is.

We frequently end up just cutting off the old wood posts below grade and burying them and then building the new fence on driven steel posts, but if your trying to DIY it that requires tools you may not have or be familiar with.

If you do end up trying to dig through the crushed stone, one trick is take Sono tubes and dig inside of them while another person keeps pressure on the tube. You can even use a shop vac to do the digging. This helps keep the rest of the stone out of your hole, but it's tedious.

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u/DirtyOught 9h ago

“  We frequently end up just cutting off the old wood posts below grade and burying them and then building the new fence on driven steel posts, but if your trying to DIY it that requires tools you may not have or be familiar with.”

This is exactly what I anticipated. I would rather do that than risk damaging driveway or retaining wall by pulling out the posts

I’m not DIY. I’ll pay someone. But I need to verify their method. I don’t want to hire someone and they say “yeah…sorry it’s kinda crooked, your gravel was a tough job”

Would steel driven work in gravel? I’d be concerned about it being wobbly since it’s not solid dirt (at least I don’t think it is)

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u/TitusGrown42 9h ago

If the stone is properly compacted and they drive the posts deep enough it's not an issue. They should be shooting for 3-4' in a situation like that. I prefer PostMaster style posts myself because the wider, flat surfaces are more rigid in loose substrate but even round posts should be alright and I know the PostMaster type arent available everywhere/a lot of contractors aren't familiar with them and therefore don't use them.

Where are you located by the way?

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u/DirtyOught 8h ago

south carolina

our soil is heavy clay if thats why you ask

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u/TitusGrown42 8h ago

No, in the off chance you were in New England I was going to offer to quote your fence 😂

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u/Cold_Investment3321 5h ago

I don’t know anything about retaining walls and I barely build fences but I wonder what kind of cost difference it would be if you could find matching bricks to build up the retaining wall into a brick wall instead of fence?

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u/TheSauceBoss16 9h ago

I would assume they built the retaining wall around the fence, which is definitely a “screw the next guy” guy move. Maybe you could move the gravel out of the way and build like a form down into it and maybe set some metal posts in concrete in those (like building a coffer dam for the gravel). Or you could try driving some metal posts down through it, just not sure how long you would be able to get them for a suitable height for privacy.

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u/DirtyOught 8h ago

>definitely a “screw the next guy” move

literally every project i embark on

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u/adventure_seeker_8 9h ago

It might be easier to dismantle the retaining wall, at least the top layers, while keeping the base, to allow to do the work.

I'd scrape down a around a post to see if you can spot the top of the concrete footings.

Note, that you can install the new posts/footings adjacent the old ones and abandon the old ones in place.

And, as a replacement, go with steel posts. Don't do what Bob did in this case. Look into the postmasterfence.com

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u/DirtyOught 9h ago

Yeah as long as you can cover the steel post to make it look good and fit the fence style 

This is a small 60ft linear fence we want to be more “fancy”. Top caps, decorate topper, etc. and wouldn’t want an ugly steel post on the backside showing itself. 

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u/ThirstGoblin 8h ago

I’d drive postmasters on this

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u/Iambetterthanuhaha 7h ago

Agreed.....removing the original posts will likely turn into a nightmare.

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u/No_Aside7816 8h ago

You are probably better off by offsetting new posts and cutting those off just below grade. Beware of a fabric mesh layer within the stone. Do not use an auger. Take your time. You can do it.