keep wood post from sticking to concrete ?

Hi,


I am planning on setting up a basketball hoop and backboard on a 16' 4x4 treated wood post - but - I want the post to be easily removable from time to time.


My plan is to dig a hole about 18" wide and about 24" deep and use fast setting concrete that hardens in about 40 minutes.
(the hole would be dug in some fairly solid clay type ground, not your normal loose garden dirt)


I wanted to put a shorter piece of 4x4 post temporairly in the concrete to make a hole that would fit a 4x4 post snugly.
(the temporary post would be just long enough to put a level on it to insure it was vertically aligned)


Question:

What can I put on the temporary piece of 4x4 treated post to keep it from sticking to the concrete when it hardens so I would be able to slide it out after the concrete hardens ?


I have searched the internet for ideas how to do this and someone wrapped the wood in plastic wrap then covered the plastic wrap in vaseline, someone else talked about using a spray cooking oil, but I wanted to be really sure to be on the safe side so I was asking on this forum.


Thanks in advance for your help !

I would use a piece of round pipe, and make a few wedges/or shims to keep it in place. It has worked many times for me. And if you get any ground movement, it is easier to remove because of the voids around it.

inspectorD said:

I would use a piece of round pipe, and make a few wedges/or shims to keep it in place. It has worked many times for me. And if you get any ground movement, it is easier to remove because of the voids around it.

Click to expand...

That is a really good idea !

Thanks, I have to give it some thought, but I just might try that idea !

(I guess if I use a pipe just barely large enough to squeeze the 4x4 post into that will help make sure it stays vertically level both ways, and the shims would help keep it from turning when you bounce the basketball off the backboard)

(with the hard clay soil in much of my yard there might not be much chance of any ground movement - good for projects like this - but rough when trying to plant a vegetable garden )

build a 4X box to go around the 4X post. Post will be removable but not the box.

kok328 said:

build a 4X box to go around the 4X post. Post will be removable but not the box.

Click to expand...

Another very good idea, thanks !

I'll have to ponder on the various possible ideas before deciding.

(a wood box would deteroriate over time, perhaps I could make a box out of sheet metal that is thin enough to bend snugly around the 4x4 and pour the concrete around that)

Thanks everyone, these ideas are helping, I'll keep thinking on them before deciding how I want to do this.

The abs pipe is the way to go.

A big disadvantage of using round pipe or tube is that unless a locking mechanism is incorporated into the system, the post and backboard will have a tendency to spin when the latter is hit hard and off-center by a basketball.

A better way to go is to use a short piece of tubular steel, with a small flat steel plate tack-welded on the bottom end. A chunk of TS 4 x 4 x 3/16 will have an inside clear dimension of 3-5/8", which should enable a standard 4 x 4 treated post (usually 3-1/2" square) to slide in and out at will, but still be firm enough to have very little wobble. You may have to trim the corners of the 4 x 4 a bit to match the inside corner radius of the tubular steel. Spray-painting the inside of the steel tube will minimize its tendency to rust. Don't paint the outside or the bottom plate, as you want your concrete to stick to them

Wood that is tight fit in a hole will swell with moisture and become near imposible to remove. Unprotected steel exposed to water air and concrete will rust and expand and break the concrete. That is why rebar is not to be within two inches of the surface of the concrete.
http://www.removablepost.com/

If nealtw's wood swells too much with moisture absorption (although allowing a 1/8" clearance has never been a "tight fit" in most parts of the world), one could always cut down and encase the wood with a steel sleeve that wouldn't appreciably change dimensions with moisture changes.

And yes, if one is truly concerned with embedded steel corroding over time due to excessive moisture intrusion, maybe all of the world's thousands of bridge foundations supported by bare steel piling embedded in concrete piers and abutments are in danger of collapse? Yikes, I hope they all don't collapse at the same time!

Hey ,I like that superpost Neal linked to! Looks like a good fit for what you are going to do.
Good luck!

I had a similar situation with a mailbox. Somebody came down my street and hit all the mailboxes as they drove along with a baseball bat knocking them over. One of my neighbors found a product that has a piece of PVC that sits in concrete and the wood fits into the PVC. It's water tight so nothing gets in to rot the post. The post can be removed but the vinyl protector stays put. It remains in the concrete and the post slips in and out in case it has to be replaced. It's been great. You might want to consider digging your hole deeper than 24 inches for such a high post especially if you are putting a basketball hoop at the top. The thing we got is called Superpost.

nealtw said:

The abs pipe is the way to go.

Click to expand...

BridgeMan said:

A big disadvantage of using round pipe or tube is that unless a locking mechanism is incorporated into the system, the post and backboard will have a tendency to spin when the latter is hit hard and off-center by a basketball.

A better way to go is to use a short piece of tubular steel, with a small flat steel plate tack-welded on the bottom end. A chunk of TS 4 x 4 x 3/16 will have an inside clear dimension of 3-5/8", which should enable a standard 4 x 4 treated post (usually 3-1/2" square) to slide in and out at will, but still be firm enough to have very little wobble. You may have to trim the corners of the 4 x 4 a bit to match the inside corner radius of the tubular steel. Spray-painting the inside of the steel tube will minimize its tendency to rust. Don't paint the outside or the bottom plate, as you want your concrete to stick to them

Click to expand...

nealtw said:

Wood that is tight fit in a hole will swell with moisture and become near imposible to remove. Unprotected steel exposed to water air and concrete will rust and expand and break the concrete. That is why rebar is not to be within two inches of the surface of the concrete.
http://www.removablepost.com/

Click to expand...

BridgeMan said:

If nealtw's wood swells too much with moisture absorption (although allowing a 1/8" clearance has never been a "tight fit" in most parts of the world), one could always cut down and encase the wood with a steel sleeve that wouldn't appreciably change dimensions with moisture changes.

And yes, if one is truly concerned with embedded steel corroding over time due to excessive moisture intrusion, maybe all of the world's thousands of bridge foundations supported by bare steel piling embedded in concrete piers and abutments are in danger of collapse? Yikes, I hope they all don't collapse at the same time!

Click to expand...

inspectorD said:

Hey ,I like that superpost Neal linked to! Looks like a good fit for what you are going to do.
Good luck!

Click to expand...

carljobs said:

I had a similar situation with a mailbox. Somebody came down my street and hit all the mailboxes as they drove along with a baseball bat knocking them over. One of my neighbors found a product that has a piece of PVC that sits in concrete and the wood fits into the PVC. It's water tight so nothing gets in to rot the post. The post can be removed but the vinyl protector stays put. It remains in the concrete and the post slips in and out in case it has to be replaced. It's been great. You might want to consider digging your hole deeper than 24 inches for such a high post especially if you are putting a basketball hoop at the top. The thing we got is called Superpost.

Click to expand...

Thanks for all the ideas, the product they have at the web site nealtw mentioned - http://www.removablepost.com/ would indeed seem to be an excellent solution.

I had been thinking about forming thin sheet metal around a 4x4 to make a 4x4 hole in concrete, but the money and added effort to use sheet metal, it seems it would be worth just getting the product at the removablepost site. The 24" would be the minimum I would get, but perhaps the 36" would be best, figuring using a 16' 4x4 and having to allow for the backboard height and having the rim 10' off the ground that should work out ok, the backboard would just extend 6" above the post.

Thanks again to everyone for all their ideas !