Last spring, after I jacked up my 3x6 oil barrel slab I posted asking
about how to pump concrete under it to keep it where it is now.

Someone mentioned a grout pump & I've been watching for a good deal on
one all summer- but no joy. My plans to build one have gone through
lots of permutations- but when I saw the psi that commercial grout
pumps operate at [several hundred psi], I decided to try some other
thoughts.

Yesterday I thought I'd make a long nozzle for some masonry caulk and
pump that in with a caulk gun- maybe I could work buying a pneumatic
caulk gun into the job.

But today, when trying to decide what caulk was more likely to expand
than shrink- I thought of Great Stuff.

The only thing Dow warns against when using outside is exposure to
sunlight.

I calculate the weight at;
36x72x4" slab- 900 pounds
275gallons oil- 2100 pounds
Barrel- 300 pounds
snow 7 ice 300 pounds

total- 3600 pounds.
area- 2592 square inches-

So even if I only managed 50% coverage, we're talking about less than
a 3psi load. The Pro stuff is rated at nearly 20psi.

I'm not trying to raise the slab- just fill the 1/2-3/4 inch gap
created when I leveled it.

I think I'm going to give it a shot unless someone has tried it with
disastrous results. It is certainly both the cheapest and easiest
idea I've come up with so far. A few cans of Great stuff and some
extra tubing to get to the center of the slab.

Any thoughts?

Jim

"Jim Elbrecht" wrote in message

But today, when trying to decide what caulk was more likely to expand
than shrink- I thought of Great Stuff.

The only thing Dow warns against when using outside is exposure to
sunlight.

I calculate the weight at;
36x72x4" slab- 900 pounds
275gallons oil- 2100 pounds
Barrel- 300 pounds
snow 7 ice 300 pounds

total- 3600 pounds.
area- 2592 square inches-

So even if I only managed 50% coverage, we're talking about less than
a 3psi load. The Pro stuff is rated at nearly 20psi.

IMO, it can work. There may be some compression over time though. Foam
insulation is used under concrete slabs all the time.

On Sat, 13 Oct 2007 11:14:33 -0400, Jim Elbrecht
wrote:

Last spring, after I jacked up my 3x6 oil barrel slab I posted asking
about how to pump concrete under it to keep it where it is now.

Someone mentioned a grout pump & I've been watching for a good deal on
one all summer- but no joy. My plans to build one have gone through
lots of permutations- but when I saw the psi that commercial grout
pumps operate at [several hundred psi], I decided to try some other
thoughts.

Yesterday I thought I'd make a long nozzle for some masonry caulk and
pump that in with a caulk gun- maybe I could work buying a pneumatic
caulk gun into the job.

But today, when trying to decide what caulk was more likely to expand
than shrink- I thought of Great Stuff.

The only thing Dow warns against when using outside is exposure to
sunlight.

I calculate the weight at;
36x72x4" slab- 900 pounds
275gallons oil- 2100 pounds
Barrel- 300 pounds
snow 7 ice 300 pounds

total- 3600 pounds.
area- 2592 square inches-

So even if I only managed 50% coverage, we're talking about less than
a 3psi load. The Pro stuff is rated at nearly 20psi.

I'm not trying to raise the slab- just fill the 1/2-3/4 inch gap
created when I leveled it.

I think I'm going to give it a shot unless someone has tried it with
disastrous results. It is certainly both the cheapest and easiest
idea I've come up with so far. A few cans of Great stuff and some
extra tubing to get to the center of the slab.

Any thoughts?

Jim

That may work. On the other hand, a 3x6 slab dont sound like it's
worth all the hassle to buy a grout pump and all of that. Thats only
18 sq. ft. of concrete, which is about 1/4 yard of concrete. You
could replace the thing with about 12 to 14 bags of ready-mix bagged
concrete (just add water). (I am not sure how many bags are needed
per sq. ft.) Or, if you have a few strong friends and some strong
boards, just lift it, put fine gravel-sand under it, and set it back
in place. But go ahead and try the great stuff and let us know if it
works.

You don't need a grout pump to use non shrink grout. Mix it a little thin
and pour it down with a funnel.


"Jim Elbrecht" wrote in message
...
Last spring, after I jacked up my 3x6 oil barrel slab I posted asking
about how to pump concrete under it to keep it where it is now.

Someone mentioned a grout pump & I've been watching for a good deal on
one all summer- but no joy. My plans to build one have gone through
lots of permutations- but when I saw the psi that commercial grout
pumps operate at [several hundred psi], I decided to try some other
thoughts.

Yesterday I thought I'd make a long nozzle for some masonry caulk and
pump that in with a caulk gun- maybe I could work buying a pneumatic
caulk gun into the job.

But today, when trying to decide what caulk was more likely to expand
than shrink- I thought of Great Stuff.

The only thing Dow warns against when using outside is exposure to
sunlight.

I calculate the weight at;
36x72x4" slab- 900 pounds
275gallons oil- 2100 pounds
Barrel- 300 pounds
snow 7 ice 300 pounds

total- 3600 pounds.
area- 2592 square inches-

So even if I only managed 50% coverage, we're talking about less than
a 3psi load. The Pro stuff is rated at nearly 20psi.

I'm not trying to raise the slab- just fill the 1/2-3/4 inch gap
created when I leveled it.

I think I'm going to give it a shot unless someone has tried it with
disastrous results. It is certainly both the cheapest and easiest
idea I've come up with so far. A few cans of Great stuff and some
extra tubing to get to the center of the slab.

Any thoughts?

Jim