Cement Pad Thickness for Water Tanks?

Posted by Scott Townsend on July 30, 2006, 4:53 pm

I'm installing two water tanks. One is an 8' Diameter 2500 Gallon tank and
the other is a 12' Diameter 5000 Gallon tank. I'd like to set them both on
a cement pad Maybe 2' wider then the tank itself.

How thick should I make the Pads?

Thanks,
Scott<-

Posted by DanG on July 30, 2006, 5:33 pm

It maybe matters a bit more on what the soil is that the pads rest
on. The loads are not extreme. The small one will weigh over
20,000 # when full resting on a base of over 48 square feet. Load
per SF = 400# plus. Most soil tables will allow 1000#/SF unless
you're in a swamp.

I would pour 6" with #4 bar each way on 1 foot centers using 3,000
# concrete or better, air entrained if in a cold climate. Cure
and do not load for at least 7 days, 28 preferred.
______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)
dgriff237@7cox.net

> I'm installing two water tanks. One is an 8' Diameter 2500
> Gallon tank and the other is a 12' Diameter 5000 Gallon tank.
> I'd like to set them both on a cement pad Maybe 2' wider then
> the tank itself.
> How thick should I make the Pads?
> Thanks,
> Scott<-
>

Posted by Scott Townsend on July 30, 2006, 9:32 pm

Thanks Dan!

I wanted a Pad as Its a much cleaner look and will give a place for the pump
and pressure tank. I was hoping to not have to go to 8" and 4" seemed too
small.

I think we are at least 28 days from filling tanks with water, so I should
be pretty good there.

What do you mean by 3000# concrete? I've heard of 3 sack, 5 Sack, etc,
though not in 3000# terms. We will be having someone come in and frame up a
Driveway ramp to the Garage, its 13' wide by maybe 20' We were going to see
if we could get the Pads all framed up by then so they can just pour the
pads with the Driveway. Would the concrete they use for the Driveway be
sufficient?

Thanks again!

Scott<-

> It maybe matters a bit more on what the soil is that the pads rest on.
> The loads are not extreme. The small one will weigh over 20,000 # when
> full resting on a base of over 48 square feet. Load per SF = 400# plus.
> Most soil tables will allow 1000#/SF unless you're in a swamp.
> I would pour 6" with #4 bar each way on 1 foot centers using 3,000 #
> concrete or better, air entrained if in a cold climate. Cure and do not
> load for at least 7 days, 28 preferred.
> ______________________________
> Keep the whole world singing . . . .
> DanG (remove the sevens)
> dgriff237@7cox.net

>> I'm installing two water tanks. One is an 8' Diameter 2500 Gallon tank
>> and the other is a 12' Diameter 5000 Gallon tank. I'd like to set them
>> both on a cement pad Maybe 2' wider then the tank itself.
>> How thick should I make the Pads?
>> Thanks,
>> Scott<-

Posted by Bobk207 on July 31, 2006, 1:41 am

Scott Townsend wrote:

> Thanks Dan!
> I wanted a Pad as Its a much cleaner look and will give a place for the pump
> and pressure tank. I was hoping to not have to go to 8" and 4" seemed too
> small.
> I think we are at least 28 days from filling tanks with water, so I should
> be pretty good there.
> What do you mean by 3000# concrete? I've heard of 3 sack, 5 Sack, etc,
> though not in 3000# terms. We will be having someone come in and frame up a
> Driveway ramp to the Garage, its 13' wide by maybe 20' We were going to see
> if we could get the Pads all framed up by then so they can just pour the
> pads with the Driveway. Would the concrete they use for the Driveway be
> sufficient?
> Thanks again!
> Scott<-

> > It maybe matters a bit more on what the soil is that the pads rest on.
> > The loads are not extreme. The small one will weigh over 20,000 # when
> > full resting on a base of over 48 square feet. Load per SF = 400# plus.
> > Most soil tables will allow 1000#/SF unless you're in a swamp.
> > I would pour 6" with #4 bar each way on 1 foot centers using 3,000 #
> > concrete or better, air entrained if in a cold climate. Cure and do not
> > load for at least 7 days, 28 preferred.
> > ______________________________
> > Keep the whole world singing . . . .
> > DanG (remove the sevens)
> > dgriff237@7cox.net

> >> I'm installing two water tanks. One is an 8' Diameter 2500 Gallon tank
> >> and the other is a 12' Diameter 5000 Gallon tank. I'd like to set them
> >> both on a cement pad Maybe 2' wider then the tank itself.
> >> How thick should I make the Pads?
> >> Thanks,
> >> Scott<-

Scott-

By 3000# concrete, Dan means a 28 day compressive strength of 3000
pounds/ square inch (ie..... psi)

that's pretty decent stuff, most residential work is spec'd closer to
2000 psi so they don't need any inpsection....it's really difficult to
make a mix that comes in less than 2500 psi

from http://www.charleston.net/stories/?newsID=94460&section=garden
The mix

There are many different kinds of concrete, and the many combinations
of rock (or gravel), sand and cement can result in various concrete
strengths.

Concrete should not be bought based on the "number of sacks of cement"
it contains. Five-sack concrete mix (five sacks of cement per cubic
yard) is not always stronger than four-sack mix.

Buy concrete based on its "compressive strength," that is, how much
pressure it will take to crush it. The higher the compressive strength,
the stronger the concrete. Concrete rated 2,500 PSI is about standard,
but 3,000 PSI is worth the extra cost.
<<<<<

from http://www.trmca.org/solutions/faq19.htm

I would never specify a four-sack mix for anything, even a footing.
Concrete is not usually by the sack designation today - most concrete
is sold by a strength designation such as 3000 psi (pounds per square
inch). A four sack mix would be equivalent to about a 2500 psi mix,
again substandard in my opinion.
<<<<

Scott, take a look at the info at the links I posted.

Talk to your concrete supplier, let them know what you're building
(flat work, a tank pad), have them spec a mix design & guarantee a
compressive strength.

The cement content (per yard) & water cement ratio are probably the
most important characteristics that drive the concrete strength. If
you're going to tailgate the stuff (not pump) you can go with bigger
large aggregate & less small agg. Bigger agg & less small agg means
higher strength with less cement. The cement is just there to "glue"
everything together; bigger large agg & less small agg means less
surface to coat with glue.

Beyond mix design, curing conditions matter most.

cheers
Bob

Posted by Scott Townsend on July 31, 2006, 1:15 pm

Hey Bob!

Thank you for all the info and Links! I'll check them out!

regards,
Scott<-

> Scott Townsend wrote:

>> Thanks Dan!
>> I wanted a Pad as Its a much cleaner look and will give a place for the
>> pump
>> and pressure tank. I was hoping to not have to go to 8" and 4" seemed
>> too
>> small.
>> I think we are at least 28 days from filling tanks with water, so I
>> should
>> be pretty good there.
>> What do you mean by 3000# concrete? I've heard of 3 sack, 5 Sack, etc,
>> though not in 3000# terms. We will be having someone come in and frame up
>> a
>> Driveway ramp to the Garage, its 13' wide by maybe 20' We were going to
>> see
>> if we could get the Pads all framed up by then so they can just pour the
>> pads with the Driveway. Would the concrete they use for the Driveway be
>> sufficient?
>> Thanks again!
>> Scott<-

>> > It maybe matters a bit more on what the soil is that the pads rest on.
>> > The loads are not extreme. The small one will weigh over 20,000 # when
>> > full resting on a base of over 48 square feet. Load per SF = 400#
>> > plus.
>> > Most soil tables will allow 1000#/SF unless you're in a swamp.
>> > I would pour 6" with #4 bar each way on 1 foot centers using 3,000 #
>> > concrete or better, air entrained if in a cold climate. Cure and do
>> > not
>> > load for at least 7 days, 28 preferred.
>> > ______________________________
>> > Keep the whole world singing . . . .
>> > DanG (remove the sevens)
>> > dgriff237@7cox.net
>> >> I'm installing two water tanks. One is an 8' Diameter 2500 Gallon
>> >> tank
>> >> and the other is a 12' Diameter 5000 Gallon tank. I'd like to set them
>> >> both on a cement pad Maybe 2' wider then the tank itself.
>> >> How thick should I make the Pads?
>> >> Thanks,
>> >> Scott<-

> Scott-
> By 3000# concrete, Dan means a 28 day compressive strength of 3000
> pounds/ square inch (ie..... psi)
> that's pretty decent stuff, most residential work is spec'd closer to
> 2000 psi so they don't need any inpsection....it's really difficult to
> make a mix that comes in less than 2500 psi
> from http://www.charleston.net/stories/?newsID=94460&section=garden
> The mix
> There are many different kinds of concrete, and the many combinations
> of rock (or gravel), sand and cement can result in various concrete
> strengths.
> Concrete should not be bought based on the "number of sacks of cement"
> it contains. Five-sack concrete mix (five sacks of cement per cubic
> yard) is not always stronger than four-sack mix.
> Buy concrete based on its "compressive strength," that is, how much
> pressure it will take to crush it. The higher the compressive strength,
> the stronger the concrete. Concrete rated 2,500 PSI is about standard,
> but 3,000 PSI is worth the extra cost.
> <<<<<
> from http://www.trmca.org/solutions/faq19.htm
> I would never specify a four-sack mix for anything, even a footing.
> Concrete is not usually by the sack designation today - most concrete
> is sold by a strength designation such as 3000 psi (pounds per square
> inch). A four sack mix would be equivalent to about a 2500 psi mix,
> again substandard in my opinion.
> <<<<
> Scott, take a look at the info at the links I posted.
> Talk to your concrete supplier, let them know what you're building
> (flat work, a tank pad), have them spec a mix design & guarantee a
> compressive strength.
> The cement content (per yard) & water cement ratio are probably the
> most important characteristics that drive the concrete strength. If
> you're going to tailgate the stuff (not pump) you can go with bigger
> large aggregate & less small agg. Bigger agg & less small agg means
> higher strength with less cement. The cement is just there to "glue"
> everything together; bigger large agg & less small agg means less
> surface to coat with glue.
> Beyond mix design, curing conditions matter most.
> cheers
> Bob
>

Page 1 of 2 1 2 > last >>

Similar Threads	Posted
cement floor thickness	May 5, 2009, 3:24 am
Water trailer for dust control, block/cement sawing, asphalt water,	July 2, 2007, 4:06 pm
plastic storage tanks and algae	October 13, 2009, 4:56 am
Water trailer for dust control, fire control, cement saw, asphalt roller, trench jetting, etc	June 27, 2007, 8:22 am
Thinset mortar bed thickness	April 2, 2008, 2:10 pm
Re: concrete driveway: thickness ; mesh or not ?	May 1, 2007, 11:38 am
smallest plywood size thickness ?	May 21, 2009, 8:19 am
Water Trailers/Water Hauler/Water Buffalo/Water Transporter by Northland Products, Inc.	July 9, 2007, 3:25 pm
Matching drywall thickness to adjacent plaster	April 23, 2007, 7:01 am
ceiling tiles Qs: pay for thickness, drop-fit type; and making non-std. tees	September 27, 2006, 2:37 am