Installing new 8ft fence, re-using existing 4ft posts
January 11, 2015 6:46 AM Subscribe
I need to install a taller fence in my yard. Two of my dogs (both hounds) have figured out they can jump the 4ft fence. I would very much like to reuse the existing 4ft posts - theyre already plumb and driven below the frost line (and it's currently winter here, so digging new holes now will be a bitch & a half).
Is there any way to effectively reuse the 4ft posts for a new 8ft fence? Ideas I've had are:
Is there any way to effectively reuse the 4ft posts for a new 8ft fence? Ideas I've had are:
- buy new 4ft posts, drill holes in the top of the existing ones and bottom of new ones, throw some rebar down the center, then braces all the way around - so that I have 8ft posts, old on the bottom half and new on the top half
- buy new 8ft posts and just attach them to the 4ft ones
Jon1270's suggestion will work, if the existing posts are deep enough and strong enough for when the wind hits your new, taller fence. Wood posts get old and rotten, and a fence that tall will produce a lot of leverage when it is windy or the neighbor's kids climb and yank on it.
posted by Dip Flash at 8:01 AM on January 11, 2015 [1 favorite]
posted by Dip Flash at 8:01 AM on January 11, 2015 [1 favorite]
You can also look at some of the systems designed to keep pets from jumping out of yards. At 4 feet, most hounds aren't too challenged to get out, but they probably brace on the top of the fence to get out. If so, you can DIY a coyote roller style system - I've seen some with PVC.
Alternately, you can build a smaller enclosure that's escape-proof (i.e. taller or with a roof) for letting them out autonomously and save your 4ft fence for when they're supervised.
posted by bookdragoness at 8:09 AM on January 11, 2015 [3 favorites]
Alternately, you can build a smaller enclosure that's escape-proof (i.e. taller or with a roof) for letting them out autonomously and save your 4ft fence for when they're supervised.
posted by bookdragoness at 8:09 AM on January 11, 2015 [3 favorites]
Could you sort of 'sheath' the old 4' posts inside of hollow new 8' posts?
posted by easily confused at 8:11 AM on January 11, 2015 [2 favorites]
posted by easily confused at 8:11 AM on January 11, 2015 [2 favorites]
Basically what jon1270's says but I'd use carriage bolts long enough to go through both posts. I think the installation is a bit simpler and you won't have to worry about them ever coming out.
You will need:
Pair of "F" clamps (not the little spreader clamps)
Electric drill
Long drill bit to match your outside carriage bolt thread diameter
hammer
crescent wrench
2' or 4' level
String
Start at one end of the fence. Clamp the new post against the old one while you're working. Check that your new post is plumb. Drill your holes about 6" from the top and bottom of the existing post, keeping in mind which side you're going to be seeing it from the most because the bit will likely "blow out" the far side of the hole and you'll be putting the washer and nut on that side. Knock your bolts through and tighten up the nuts. If you want the tops of the fence to all run level, install your next post at the far end and run a string tight between them. Adjust the post until the string is level, adjust post for plum. Use the string to guide the installation of the other posts.
Dip Flash raises a really good point. I think an 8' fence would look kind of monstrous. Would a 6.5' fence not do the job? You don't need a power saw to cut the posts. A new aggressive toothed hand saw will do the job right quick.
posted by bonobothegreat at 8:22 AM on January 11, 2015 [2 favorites]
You will need:
Pair of "F" clamps (not the little spreader clamps)
Electric drill
Long drill bit to match your outside carriage bolt thread diameter
hammer
crescent wrench
2' or 4' level
String
Start at one end of the fence. Clamp the new post against the old one while you're working. Check that your new post is plumb. Drill your holes about 6" from the top and bottom of the existing post, keeping in mind which side you're going to be seeing it from the most because the bit will likely "blow out" the far side of the hole and you'll be putting the washer and nut on that side. Knock your bolts through and tighten up the nuts. If you want the tops of the fence to all run level, install your next post at the far end and run a string tight between them. Adjust the post until the string is level, adjust post for plum. Use the string to guide the installation of the other posts.
Dip Flash raises a really good point. I think an 8' fence would look kind of monstrous. Would a 6.5' fence not do the job? You don't need a power saw to cut the posts. A new aggressive toothed hand saw will do the job right quick.
posted by bonobothegreat at 8:22 AM on January 11, 2015 [2 favorites]
so, anything more than a 6' tall fence technically requires a building permit (at least as far as I know per the generally widest adopted building code). Hardly anyone ever does however. Forces and such start going way, way, way up as you get much above that and the mass and area under the fence gets larger the taller you go so it really should be engineered. Especially if you are in the maritime area of Virginia (wind loading is harsh mistress).
Would just taking of the 4' fence boards and putting on 6' fence boards work? This would be using the existing 4' posts. that is a pretty tall fence (standard these days for new residential construction) and most dogs can't clear that easily, especially without a broad top to land on/brace on for clearing.
posted by bartonlong at 10:17 AM on January 11, 2015
Would just taking of the 4' fence boards and putting on 6' fence boards work? This would be using the existing 4' posts. that is a pretty tall fence (standard these days for new residential construction) and most dogs can't clear that easily, especially without a broad top to land on/brace on for clearing.
posted by bartonlong at 10:17 AM on January 11, 2015
bartonlong has raised a point that you might be well advised to look into. Installing a fence over 6' might take a building permit and/or permission from the neighboring owners. Restrictions in your area should be on file with your county.
posted by Cranberry at 12:12 PM on January 11, 2015
posted by Cranberry at 12:12 PM on January 11, 2015
Hot wire that sucker. Seriously, an 8 foot fence will not be significantly harder for a hound to escape than a 4 foot (ask me how I know!). They climb up the stringers.
Get fiberglass wands for each post and run one-three strands of electric fence, tape or net. The visible kind is best, because they come to respect the net/wire/tape itself and often if the fence goes down they won't try to escape. You ideally want to hit them on the nose or paws so consider your dogs and install as needed. Last friend I helped do this only needed one strand about 4" above the top of her fence to completely eliminate escapes (as long as it's in, her dogs will look at the charger to see if it's blinking).
It's easy to install, any farm or urbam chicken supply store can hook you up.
posted by fshgrl at 12:18 PM on January 11, 2015
Get fiberglass wands for each post and run one-three strands of electric fence, tape or net. The visible kind is best, because they come to respect the net/wire/tape itself and often if the fence goes down they won't try to escape. You ideally want to hit them on the nose or paws so consider your dogs and install as needed. Last friend I helped do this only needed one strand about 4" above the top of her fence to completely eliminate escapes (as long as it's in, her dogs will look at the charger to see if it's blinking).
It's easy to install, any farm or urbam chicken supply store can hook you up.
posted by fshgrl at 12:18 PM on January 11, 2015
Fence regulations vary too much by location to generalize, but you definitely will want to check your local rules because being forced to tear out the new fence and start over is not fun (or cheap). Where I am now six feet is the maximum in residential areas, but I've lived in plenty of places where that is not the case, for example. It is just as important a question as your core question about how to attach the longer posts, though, in terms of having a successful project.
posted by Dip Flash at 12:19 PM on January 11, 2015 [1 favorite]
posted by Dip Flash at 12:19 PM on January 11, 2015 [1 favorite]
Yep, Nth-ing that this is an engineered solution to a behavior problem (i.e., eventually won't work). I'd go with the electric wire. No experience with the "invisible fence" dog collar thing.
her dogs will look at the charger to see if it's blinking
Smarter dogs than mine in my teenage years. We put up electric wire to keep him from getting into the jalapenos and eating them all. He got the message, and from there on out all we had to do to keep him in/out of places was string up a single strand of kite string at doggy-shoulder height and he wouldn't even attempt it.
If you really want to do this, I think jon1270/bonobothegreat's suggestion of attaching the new posts to the side of the old ones with carriage bolts is best. But yeah, wind load plus the sheer weight of an 8ft wood fence is going to want to pull those existing poles over or break them. I hope there are a lot of them at close intervals.
posted by ctmf at 2:07 PM on January 11, 2015 [1 favorite]
her dogs will look at the charger to see if it's blinking
Smarter dogs than mine in my teenage years. We put up electric wire to keep him from getting into the jalapenos and eating them all. He got the message, and from there on out all we had to do to keep him in/out of places was string up a single strand of kite string at doggy-shoulder height and he wouldn't even attempt it.
If you really want to do this, I think jon1270/bonobothegreat's suggestion of attaching the new posts to the side of the old ones with carriage bolts is best. But yeah, wind load plus the sheer weight of an 8ft wood fence is going to want to pull those existing poles over or break them. I hope there are a lot of them at close intervals.
posted by ctmf at 2:07 PM on January 11, 2015 [1 favorite]
you could just put 8 ft lattice panels up. Screw them to the existing fence long-end up. As a bonus they're easy to remove.
posted by blue_beetle at 2:27 PM on January 11, 2015 [2 favorites]
posted by blue_beetle at 2:27 PM on January 11, 2015 [2 favorites]
Yeah, what jon1270/bonobothegreat said (definitely use bolts rather than screws), but think seriously about whether you really need a fence that high. The wind loadings will be enormous and I seriously doubt the ability of the existing posts to take that kind of load for long. An 8' high fence is starting to get into territory where you need an engineer to develop foundations for it and I doubt you want to go there any more than you want an 8' high fence falling on one of your neighbours. I wouldn't go higher than 6' with the existing posts as support.
Check with your local government requirements, as fences this high are generally considered unacceptable. Also check if you are thinking about installing any kind of electric fencing as these are also often not allowed in urban environments.
posted by dg at 4:06 PM on January 11, 2015
Check with your local government requirements, as fences this high are generally considered unacceptable. Also check if you are thinking about installing any kind of electric fencing as these are also often not allowed in urban environments.
posted by dg at 4:06 PM on January 11, 2015
You can do something like THIS using construction tie plates. Most large hardware stores will have them.
posted by boilermonster at 9:41 PM on January 11, 2015 [1 favorite]
posted by boilermonster at 9:41 PM on January 11, 2015 [1 favorite]
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posted by jon1270 at 6:53 AM on January 11, 2015 [7 favorites]