Installing 4x4 sign Posts

[hokiegrad09]

Hello All, I am not new to signs (have been in business 10 years) but I am about to install my first construction site sign, it is actually going to look exactly like the sign in the attachment. My question is do i need to use concrete when installing this sign? I used concrete when I installed my fence in my back yard but that is more permanent. This sign will be up for 6 months to a year. Any help would be greatly appreciated. Thanks!

 

[GaSouthpaw]

You're probably going to get both views on this (for and against)- but I'll cast the first vote: Use a bag for each post. Better safe than have to waste time putting it up again for free if someone- or nature- knocks it down.
Just make sure the customer spots where it's going so you can recharge them when some committee wants it relocated!

 

[k.a.s.]

If you tamp the dirt back in right then no, it is possible to get a very tight post without concrete. That said, a bag of post set can't hurt and it is necessary it you have wet or muddy ground that does not pack.

Kevin

 

[Johnny Best]

As the others have said, just get some 50lb bags of fast setting concrete to be on the safe side in case of high winds. And if the ground is wet you won't have to add water to the mix. One bag per hole should be enough.

 

[Cross Signs]

I wouldn't' bother with concrete on a sign like this. But I would put 30'' - 35'' inches of post into the ground, and pack it real good when refilling the hole. Here in Florida. I can dig a hole, drop a 4 x 4 post with a PVC sleeve around it. And pack more dirt back in, than I took out.

 

[Billct2]

Like has been said, either will work. Especially on a three legged set up, but it really depends on the digging. If you can get 30-36" down and the ground is hard concrete is optional.

 

[SIGNTIME]

red bag... $18 is cheap insurance

 

[Gino]

That looks like a 4' x 8' with a bottom extra foot or 15 inches with a 2' to 3' span out of the ground. So, something not seen in your picture from that angle and no one has mentioned, but when we do a 'V' shape sign like that, we will run two stringers from outside post to outside post. That will give it quite a bit of stability. Also, something so short term, I would not waste cement on it. After digging about a 38" hole, I'd pack it back in every few inches with the back side of your digging bar and then mound it.

 

[hokiegrad09]

Thanks so much for all the info guys. I think the first thing I need to do now is ask the builder exactly how long he wants the sign there for and if he may want it moved later. The 6 months to a year was just what the realtor estimated. I would feel more comfortable with concrete but i don't want to have to dig it up and move it in three months. Thanks!

 

[Modern Ink Signs]

And a line to your quote for the concrete and let your client decide if they want to deal with it when they are done.

Don't forget about having to transport water to the site as well....

 

[JohnBFryJr]

Depends who is removing the sign. If I am the skip it. But all the dirt here is gumbo so it's concrete anyway.

Sent from my SAMSUNG-SM-N910A using Tapatalk

 

[MikePro]

i've installed the exact same sign type, and it was only meant to be up a few months. Two years later, it still is there because construction still hasn't finished.

installed 36" below grade, with about 2' of gravel&sand at the base. the rest is soil/sod we packed back on top. ready to pull straight out of the ground whenever they get around to it.

other option is to make T-frame legs and sandbag them to keep it weighed-down, or pound rebar stakes through them down into the ground.

 

[Moze]

I would use a bag of Maximizer on each post. It's about $8 per 80 lb. bag. An 80 lb. bag of Maximizer is larger in size than an 80 lb. bag of Quikrete. I typically remove any dirt from the site and the bags work great for hauling off the dirt.

You mentioned moving it...are you having to move it to another site?

 

[signbrad]

A triangular installation like this is very stable even without concrete, assuming 36-inch holes. Adding a horizontal stringer in back per Gino's suggestion makes it even more stable. I have installed signs as large as 8x10 in this manner without concrete. Of course, soil varies with the location as does wind. And concrete is indeed cheap, unless it's ready-mix. And I have dumped many a bag of Quikrete into holes without water.

I built two highway lease bulletins in my Arkanasas days. They were 10x20, double-sided, on 25-foot utility poles. I hand-dug five 6-foot holes for each. (I had a jab digger with 10-foot handles). On the first sign, I put a couple bags of concrete mix in the bottom of each hole, then backfilled. On the second one I splurged and called the ready-mix guy. Neither bulletin leaned for the ten years I stayed in Arkansas.
By contrast, I built an 8x16 using four 8x8 square posts, 20-feet long. The holes were four feet deep with concrete. The posts were snapped off at the base within two weeks by high wind. This was not a leased board, but an entrance sign for a refinery. They paid me to re-install, acknowledging that the winds were excessive, though I added a fifth post.

MikePro's practice of pinning a frame to the ground with rebar works great. I have done the same thing, but used 1/2-inch EMT conduit instead of rebar. When you drive a 3-foot length of conduit with a 2-pound hammer through a 2x4 or 4x4, the walls of the tubing at the end begin to roll over from the striking of the hammer, creating a kind of lip. By the time the end of the tubing reaches the framing member, it has developed a "nail head" that pins the wood nicely. It helps if the hole drilled in the wood for the conduit is not too big, allowing a snug fit. I always used this procedure for pinning down kickbacks whenever I used them.

Brad in Kansas City

 

[ams]

You are in my neck of the woods. I usually always use 1 bag per post. However if you don't want to mix it and carry it around, you can now buy liquid concrete. One bag replaces two 50 lb bags of concrete, it's $10 a bag and it's a green liquid. Pour it in and it creates a foam and dries solid in about 10 minutes. Very quick.

 

[TammieH]

also, Pea gravel is an excellent fill, a bonus if you are in a construction area you can usually confiscate a bucket or two of pea gravel
you kind of pack it down like you would with soil but use the sharp end of the tamper.

 

[bob]

Just dig a trio of holes maybe 30" or so, insert post, back fill in three lifts, pack each lift with the handle of your shovel. It won't go anywhere.

When you back fill always, as in always, push the dirt onto the shovel towards the hole, never away from it. That way you'll have enough dirt. If you don't then you'll spread the fill dirt out away from the hols and you'll end up wondering why you didn't have enough dirt.

If you just have to use concrete then dump a bag of mix in each hole and pack that just like it was fill dirt. Top the concrete mix off with fill dirt, packed via shovel handle, to bring the hold up to ground level if necessary. Use real live concrete mix not some anemic post mix. In 99.9% of the places you dig you don't need to add any water to the concrete mix. There's sufficient moisture in the soil to wet the mix and cause it to set. Remember that concrete setting is a chemical reaction and has precious little to do with evaporation. That's why you can pour concrete under water and it will cure completely. It takes 28 days for concrete to completely cure, more than enough time to wick enough moisture to set off the reaction. If you don't have any faith in ground moisture then dump a quart or so of water on top of the packed dry mix before you level things up with fill dirt. You don't have to mix it, just dump it in.

Having probably installed more posts over then years than all the rest of those drifting in these waters combined I know from whence I speak. The ones that have not deliberately been removed are still standing. Not just posts to hold up trivial signs, but countless posts to contain restive livestock as well.

 

[GettysburgSigns]

Sorry, LONG post, but if it's worth doing ...
In 41 years, I've hardly ever used concrete for 4x4 posts, or 6x6 posts, except when it was requested (and even then, with cautions mentioned below).

What nobody above mentioned (unless I missed it) is this:
When a post with a concrete blob on the bottom is rocked, shaken, or hit (usually by construction or lawn equipment), there will be some movement - especially with softer ground.
Once a post WITH concrete moves, you cannot just rock it back into place - the concrete blob acts to resist setting it upright again.
Particles of dirt, rock, etc., will settle in beneath the blob, making it impossible to set again - not to mention that it has already rocked itself into an unnatural state ... and both posts will do this at different frequency, so the sign will be crooked, and un-level.
But, a post WITHOUT concrete will just rock back and forth within the earth "pocket" around it. If there is a slight difference between post levels, it is a cinch to lift one side to adjust - try THAT with concrete on it!

The little bit of "peace of mind" afforded by, what effectively amounts to "making a 4" post into a 5" post", is not worth the efforts.
It is NOT the added weight of 50lbs of concrete that matters, the sign is PLENTY heavy enough to support itself.
What it boils down to, is the soil surrounding the posts - If this were a very tall, single-post sign (like a metal-posted electrical sign) there are all sorts of engineering formulas to follow - wind load; surface area; soil; area; etc. - and they usually end up with a 4x4 foot cube of concrete, and then some!

But, here's the trick to MOST signpost installs:
1) To begin, dig the holes* and place the sign into the holes, and get it "nearly level" horizontally at this point. It will take a few inches of soil to "hold" it temporarily, but it will move throughout all of your tamping anyway - so save the "true level" until step 4.
2) Fill all sides of the hole with ONLY 6" of dirt around the post, tamp the hell out of it!
3) Add another 6" of dirt, and tamp tamp the hell out of it more, but this time - check your Vertical level.
4) Add 6" of dirt, tamp the hell out of it again - now it is getting pretty stable, so you can adjust your horizontal and vertical levels to near perfection.
5) By now, you are LOOKING for dirt, because for some unknown reason, an 8" x 8" hole does not provide enough dirt to properly re-fill its own cavity - even with a 4" x 4" post placed into the middle of it! Actually, there IS a reason - you have just removed a quantity of soil, and over time, most soils have "aerated", and you have just compacted it more than the surrounding earth!
6) Sure, some of these guys will swear that concrete is the reason their signs don't move, but I think that is anecdotal, and not causal - they probably would not have moved anyway, if the ground was compacted securely, as described above.

Remember: These 4'x8' signs are on 4" x 4" x 8' (or 10') posts, which you are planting 25% to 30% into the ground. The weight of the materials alone, will not allow the signs to just "blow out of the ground" - gravity, and the mechanical "locking" action of the soil, are at work here
I have RARELY had to re-tamp a sign, and if so, it was due to extremely heavy winds, and rain-soaked ground, combined.
If I had used concrete, the winds would have STILL rocked it in that particular soil anyway.
The difference? If it had concrete, I couldn't have just rocked it back into place, and tamped it back in five or ten minutes

* Sometimes it is nearly impossible to get to that "Optimum 36" hole depth" - IMPOSSIBLE, without major digging apparatus.
Many times, at least in our local Gettysburg, PA soils, I'm lucky to be able to hand-dig to a 24" depth, and sometimes I have to settle with 18" in one hole, and 24" in another.
I'm talking MAJOR rocks at a 12" depth sometimes, and having to totally relocate, because I don't have dynamite
But again, since the stubborn soil in that particular sign area is extremely stable - if you use the above methods, the sign will remain secure.

 

[boxerbay]

You should check your local city ordinances. You are in Florida and many have ordinances about signs in hurricane areas. That sign in a hurricane turns into a 4x8 flying guillotine. Check you city ordinance code enforcement and do it right. I dont want to find your sign in my trucks windshield after the next hurricane.

 

[Johnny Best]

Or in Florida the 4x8's stolen before the storm to put over windows for protection during the hurricane.