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Replace or Repair some old 4x4's in concrete?!?

2127 Views 3 Replies 3 Participants Last post by  atmcl

I'm new here, so forgive if I leave out any pertinent information that would make helping my any easier. I'm also a bit long winded, so I'll apologize for that as well.

I've just bought an older house and have a long list of honey-do's to keep my summer weekends busy. Everything has been going fairly well so far, but next up on my list is replacing the gate between the driveway and the back patio, between the detached garage and the back door. The current wood is fairly worthless, and most of it desperately needs to be replaced. The problem is that the 4x4 posts are sunk into the concrete slab that makes up my back patio and driveway. The 4x4's aren't in the best shape, but aren't rotted out and are still sturdy. They're ugly as sin, but don't have to be replaced.

My brother-in-law suggested replacing everything but the 4x4's, and just using some wood-putty to fill in the holes where the old rusted bolts and screws have left holes and weathering. Then just sand and stain it with the rest. This will work, but I'm not convinced it's the best choice. I don't want to build a nice new gate, and have some nasty looking posts drawing the attention away from my hard work, but that may be the best (and cheapest) option at present. However, this will be a pain in the rear end, since the original 4x4's are warped a bit and no longer perfectly straight or plum. The railing won't be a big issue, but hanging the swinging gate will be that much harder.

I've considered just taking the old 4x4's out, but replacing them puts me in a bit of a quandary. I don't want to rent a jackhammer and dig out 2 holes big enough to plant and cement 2 more 4x4's unless I absolutely have to. I've read about the brackets that I can bolt into the cement, but those don't seem like they're a good choice either. I live in Houston, Texas. We have an occasional freeze, but no freezing/thawing season to speak of. We do have the occasional hurricane though, and I don't want this thing coming out of the ground and playing bumper cars with the property. Also, with the bolts, I am assuming I'd have to reposition the new beams so they're no on top of the old ones. I don't have any idea how hard removing the old wood from their holes would be if I decided to cut the original 4x4's down as low as possible, but what if I can't get all of the old wood out from below the ground level? I haven't found a good DIY guide for that situation.

And to top if all off, I will eventually be building a larger deck for the backyard. This includes adding a roof to the area between the garage and the house, so I would need to either put in some taller (and most likely deeper planted) supports. I don't have to use the gate's 4x4's to support the roof, but it would be the more aesthetically pleasing than other ideas I've managed to come up with.

Anyone have ideas / suggestions / warnings / comments on what would be best? I'll give some basic dimensions and attach some crudely drawn MSPaint sketches to show the basic layout of the gate, if that will help anyone with a good foundation in structural integrity. Forgive the not-to-scale and floating pieces. I just wanted to give a visual layout for what I'm dealing with and would like to accomplish.

On the left is the garage that I can fasten into, and on the right is the house (The current gate a surrounding fence is tied into the walls already.) The 4x4's are each planted about 34" away from the walls (garage and house) and they are about 42" away from eachother. The 4x4's are about 60" high from the base of the concrete to their top. Here's a crude picture.

Here is a basic picture of what I'm intending to build. I would like to add some height to the fence, and make it look nice. The top portion would add another 12" to the top, or 18" if I start feeling adventurous. I'd prefer that the 4x4's go all the way to the top, instead of having to add height on top of the existing ones, but the amount of extra work that it appears to be needed for it seems quite high.

And again, in the moderately near future (next summer, probably the next tax return as long as nothing major pops up) I'd like to build a deck with a covering over this area, so using 4x4's as supports would be ideal, like this.

The roof would be ideally be about 9' high, and I can tie it into the house and garage as well, but that's a whole other DIY issue.

So, long story short for those still with me, what are my options as far as the old 4x4's? Should I just grit and bear it for now, replace them later, are the brackets sturdy enough to hold it, considering it's not that long and attached to the house and garage, where can I place the brackets, does anyone want to help me build it if I supply the pizza and beer, what's the best way to solve the problem, and/or what would you do if it where your own gate?

If I have to, I'll do it the hard way and spend the money on the extra tools I'll need to rent. But if there is a better way that will get the job done well, I'm all for the advice. I don't need it to survive a category 5 hurricane, but I don't want my dog to run at it and knock it down trying to eat the UPS guy who's dropping a package by the back door. :laughing:

Thank you for any ideas or advice?
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Well, until you got to the part about making the fence higher, I was going to suggest you just cover the posts with 1x. Extending the height of the 4x's is kind of an iffy thing, a saddle joint is about all I can think of to do that.
I have seen cases such as yours and the posts were covered with a vinyl sleeve and cap. I haven't used these myself, but it appears that the sleeve is dropped down from the top and held in place with the cap.

How about this?
Slipping PVC or vinyl sleeves over the 4x4's just adds different problems into the mix. Either they will be bowed with the original 4x4's they're encased in, or there will be significant gaps between the top and bottom between the sleeve and post since they are leaning off keel. I've pretty much decided on replacing the posts, since I'll need to add height in the near future and there is no way to do that without new posts. So I guess this thread is what's the easiest way to get these out of the ground, while damaging the smallest amount of area around them?

I have no idea how deep the posts are buried, but I'm hoping only 1' down. If I'm unlucky, it'd be 3'. I don't look forward to opening a 1'x1' hole in the patio, then having to dig 3' down in concrete and gumbo-mud trying to get these monstrosities out of the ground, but I'm struggling to accept a reason other than laziness about doing it any other way. I also don't want to go through $400 in bits trying to slowly eat away the wood. I'd rather rent the tools for $200 and repair and level the concrete holes. I plan on decking/putting pavers over most of this area anyway, so as long as it doesn't cause structural problems I'll be okay.

Do you have experience with epoxy? I've read about different people using it, but I can't find anything about anyone having to go through what I'm about to try to do.

I've half decided that if I'm going to do this, I'd rather do it the hard way once instead of doing it the makeshift way three times. Unless someone on any of the forums I've asked this on comes up with a good idea, I'm just going to rent a concrete saw and cut out a square around the original posts. Then I'll break up the concrete and hopefully figure out a way to uproot the whole mess without destroying the concrete patio and driveway slabs.

If I'm lucky, the concrete around the post won't go all of the way down, or it'll only be 1' down. Then I can dig out a new hole with a clamshell and spend the next few weeks hating cement.

Anyone have experience breaking up concrete around posts? I can't dig around it, so It'll be hammering away until I've got enough loose to pull out the pieces.
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