If you guys approve I will be pouring concrete for a basketball post
tomorrow in PA. For the weather in my area see,
The pour requires about 1000lbs. of concrete and will be hand mixed (2
foot diameter hole x 2 foot deep).
To combat the cold I would do the following,
1. Use warm water and buy the concrete from the big box the day of the
pour to keep the concrete as warm as possible.
2. After the pour place 2-3 reflector lamps with 100w bulbs on top of
the concrete and then place about a cubic yard of bat insulation on
top of the reflector lamps and lay a tarp over all the insulation.
3. Let the concrete set up for a week.
After a week will the concrete likely be ready for winter?
Thanks for any help or suggestions!
I don't think you need do anything more than cover it
up with some simple insulation, or old coats, etc.
It's only going down to upper 20's overnight, no?
Also, I haven't done the math, but 1000 lbs for a 2ft
diameter hole, 2ft deep doesn't sound right.
I am thinking there was 80 pounds in a bag of sackcrete. Anyway I can tell
that it takes about 45 bags to fill a hole about 3 feet each way (cubic
yard, 27 cubic feet). I did that.. Too much trouble to get a mixer truck in
where it needed to go.
There was thread back in 2010, Sept 23 about concrete volumes
~.45 cu ft for 60lb bag
~.60 cu ft for 80lb bag
But a yd of cured concrete (@150 lbs/ cu ft) is 4050 lbs.
But these two sets of data dont match up because the dry bags are w/o
water and the yd of cured has gallons of water that's been "hydrated"
Here's what the mfr of sack concrete says
10-day forecast shows (as you would expect) temperatures at or below
I question why you want (or must) pour now, vs in the spring. Do you
intend to play basketball in the next 2-3 months?
A very strange design for the hole.
Why didn't you rent a post-hole digger and drill an 8" or 10" hole, 3 or
4 feet deep?
You would end up using less concrete, and the pole would be MORE secure.
The hole as you describe would need 900 lbs of concrete. A 10" diameter
hole, 4-feet deep would need 300 lbs of concrete.
The first 12 hours after you mix and pour are the most critical in terms
of the water in the concrete freezing before the hydration reaction has
completed. You will lose lots of heat to the surrounding ground. The
concrete itself will generate a surprising amount of heat as it cures
(this heating effect will peak about 8 hours and end 8 hours after
It would be better to place some heaters *in* the hole (electric,
propane, etc) and cover the hole with something (heavy plastic, sheet of
plywood, etc) for a few hours before you start to pour. After the pour,
if you cover the finished concrete with plastic, and then place
insulation (straw, fiberglass, etc) then that's all you need to do.
You don't need to *add* heat to the concrete as it cures - you just have
to do what you can to insure that it retains as much of the heat that it
generates on it's own as it cures. That means preventing it from being
exposed to the surrounding air and wind.
Leave it covered with the plastic and a sheet of plywood for at least a
But I still say the hole should be smaller and deeper, and unless you
have a dire need to do this now, do it instead in april or may.
Thank to all for your advice! This is a job I am doing for someone. I
think it might be a Christmas gift. The weather can get basketball
nice inbetween the nasty cold. Also I accepted the job knowing I could
not do it right away so I feel obligated to do the work unless it is a
really bad idea. It is my understanding that the concrete must reach a
certain strength before it can resist freezing. For the next week the
uncovered ground is likely to freeze only an inch or two so if I keep
in the heat with the insulation I have onhand that I should be safe.
Hope 2013 is a good year for you all!
If frost goes deeper than 2 feet in your area, your post will be pushed out
of the ground by the frost if your concrete is only 2 feet deep. It may take
a couple of winters or more but frost can push a shallow post up until it is
unstable and it can actually eject it out of the ground and have it fall
over. Deep is the way and even then if frost can grip the sides of the
concrete it can move it up a few inches each year. I have used Sonotubes and
wrapped them in a plastic garbage bag to make the outside slippery enough so
that frost will not move fence posts.
Yes, this is true, and in PA (where the OP is) this will happen to him.
But he seems to be in a dire need to pour this basketball post NOW,
presumably so that he can throw some hoops with his family during
christmas holidays (at least he thinks that will happen - the reality is
likely to be somewhat different).
Making the sides of the posts "slippery" is not necessary - that is not
why posts move as a result of frost heave.
There has to be frozen water under the bottom of the concrete pier or
post for the pier to move. If the pier is deep enough - the soil under
the pier might be damp but it will not freeze.
I don't know the answers to your questions, but I did some searching on the
topic -- including searching for the frost line in Bucks County PA (which is
not far from me).
First, about the frost line, ere are two links that give some information:
The second link has a "Map 2" which appears to show the frost line for your
type of application in Bucks County as being 36 inches.
Also, of course, be sure that there are no underground gas lines or
electrical lines where you will be digging.
Here's a Google search on the topic:
If you look at the Dick's Sporting Goods site, it suggests a hole that is
16-inches in diameter and 36-inches deep, with a slightly wider diameter
(20-inches) at the very bottom.
And, finally, try going to http://YouTube.com and doing a search for the
----> in ground basketball hoop installation <----
That gives a lot of useful YouTube videos on the topic.
About the "how to keep it from freezing" idea, I think your idea or
something similar would work -- meaning safely putting some type of heating
source like a light bulb above the concrete and safely covering it with
nonflammable insulation etc.
Good luck, and let us know how it turns out.
You don't need to add much heat - curing concrete heats itself.
Generally covering with a 1 foot layer of straw does the job. Make
sure the mixture is on the dry side (no excess water) and stranger
than normal. Th extra cement will speed up hydration (curing). Calcium
Chloride added to the mix will help it heat too, but it is corrosive
to metal (like your steel post).
Using warm water for the mix will help too.
On Sat, 22 Dec 2012 05:11:25 -0800 (PST), andyeverett
No one has mentioned this, so I'm probably wrong. And I've only
poured one 4'x4' slab of concrete so I have no experience.
But I thought one had to keep the concrete wet for the first several
days. That you can't just cover it and leave it, even if it is warm.
When your typical home-owner makes concrete, they're going to make it
really sloppy with too much water. So when it's poured, a lot of water
will rise to the top. If this concrete is contained by a form, there
will be lots of water sitting on the surface.
(Where the OP is going to get a 2-foot diameter sono-tube, I don't
know. You don't find them that big at the Home Despot).
Professional concrete is mixed with as little water as possible, and
when it's poured in the summer, you don't want too much water to
evaporate from the surface too quickly. The surface of the final
concrete can be weakened or too porous if this happens.
In this cold weather, with sloppy (overly wet) concrete, this is not
going to happen.
I am in pittsburgh, and the ground hasnt frozen solid yet, thanks to
the unseasonably warm weather.....
this is probably the case for the OP too....
so freezing concrete isnt a big issue just cover with a bale of
hay....concrete produces its own heat while curing so just ignore this
I too would go to 36 inches deep and smaller diameter....
a neighbor did one a foot in diameter that lasted for many years, till
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