Fences and Gates - Hole depth for 4' chain link and 6' privacy fence.

I am planning on putting in a 4' chain link fence across the side and back of my property, and a 6' privacy fence across the front, coming off the corner of my house. My question is, how far down do the posts/holes need to go? According to several sources online I am supposed to go below the frost line which is about 5' in this area - yet the list of materials shows 6' long line and terminal posts for the chain link fence, and 10' cedar posts for the wood fence which would leave only 2'/4' of post to go into the concrete. Wouldn't the concrete crack where the post ends, negating the benefit of going down so far? Do the posts on either side of a gate need to be bigger/longer/deeper? A possible note of importance: we have some very expansive clay soil around here.

I wouldn't mind going all out and boring all the holes down to 5', but I will end up digging half of them by hand since the utility companies ran their lines right next to my back and side property lines! (BTW, what is the point of hand digging? I'm pretty sure my shovel will go right through their cable/gas/power lines...)

Going down 2' to 4' is fine, UNTIL you put frost into the equation. That changes everything.

You need the bottom of the holes to be below the frost line. It works best if the holes are a bit bell shaped -- wider at the bottom than they are at the top.

When the soil freezes, it will be pushing the posts down, not up.

Get the area USA'd (Undrground Service Alert) and don't dig in the areas where they say they have lines, even if it means giving up a little yard space. It's called CYA!!

If you dig without getting the utilities located, or dig in an area where they tell you the lines are at, you could very likely be held liable for the cost of repairing any line that you break.

If you get them marked and dig elsewhere and break a line, that will be on the utility co. for giving you bad information.

Thanks, the input is much appreciated!

I've already ordered the lines to be marked since I'm planning on digging the holes this upcoming weekend. Electric and cable came out right away, but gas and telephone still haven't marked, and the electric markings are disappearing already (They ran out of flags that day, so it's just the paint on the grass.) What I do know is that right on the other side of my rear property line there is a cable line, and 6" to 3' on the inside of my property line there are some electrical cables. (They didn't go straight when they cut across the back to get to my neighbor's house.) Anyway, to completely avoid any area within 2' of a marked line, so far I would have to set my fence back 5' from my rear property line, and 3' back from my side lot line - and I still have two more utilities to go... :(

Anyway, I thought it was OK to hand-dig within 2' on either side of the line they mark. If not, I'll lose 575 sq ft out of a 6300 sq ft lot!

Your call.

Just be aware that that first, their marks aren't perfect. The line might actually be a couple of feet either way from their mark.

And I'm guessing that they have easements for those lines. Whether you own the ground or not is immaterial -- you shouldn't be building within their easement.

I lost 700 sq.ft. of my 9800 sq.ft. lot across the south side due to utility easements. I've choosen to respect them -- that's what they are.

Thanks again, I never thought about a utility easement - do you know where those are recorded? (The frustrating part is that my property backs against a wide open park - where they could have run all the lines in the world - but they decided to hog my back line.) :thumbdn:

City or County bldg. dept., County Assessor, or the County Recorders office should each have that info.

There's alot of places where the utility easement straddles the property line. Generally, you're not allowed to build a garage or permanent structure on there (but you can get a variance perhaps). A fence is usually allowed, since it's not 'permanent', but check your bylaws.

Hopefully, once everything is marked out, you have enough of a window to place your posts. The distance from a utility mark to where you can use a power tool to dig varies from place to place (our telco is 3 feet each side of the sprayed line).

One option you might consider, is a hydro-vac truck. They use a big vac hose (and high pressure water if required) to basically suck out a hole. They dont damage util lines, but of course if a line ends up right where you want the hole.. you cant move the line so you must move the fence posts.. if they could drive that sucker truck into the parkland it would be easy access for your rear fence. I know Id probably be happy to spend the $200 or $300 on a vac truck instead of digging 6 deep holes in clay... but Im gettin old and lazy.. lol

If you're going to use sonotubes (those cardboard tubes) for the concrete, they make bell shaped ends that you just tape to the end of the tube. Gives you a perfect frost heave resistor there. The hole has to fit the bell-end tho, so a bigger hole and more gravel/sand to fill the space up.

Last thing ya wanna do is avoid a good job. Makes for easy work now, but in 5 yrs or so and you have a leaning fence with the posts stuck in concrete and a big bill to try and fix it.

Have you thought about how to do the end posts at the house ? I opted to go with a corner post about a foot away from the house, then I used brackets to attach a steel bar to the house and bridged a short length of fence across there.

I just checked with the County Recorder's office and they have no record of an easement, so I think I'm just going to dig very very carefully. Oh, and I figured out why I can't see the power line markings very well - they used red paint and I have difficulties seeing red on green/green on red. :) (I'm going to have my wife go over the red lines with some blazing pink paint.)

Thanks to both of you, it's definitely appreciated.

Now be careful!!

When an area is USA'd, there are 5 different colors of paint that are used to mark off the buried utilities.

Red is electric.

Blue is water.

Green is sewer.

Orange is telephone and TV cable.

Yellow is gas.

If it was marked with red, that's a buried electric line, and a shovel can DEFINITELY cut into it. And that's not houshold current or voltage that you are dealing with. That's a minimum 6Kv line -- it'll destroy your shovel and absolutely ruin your day!!