David Hendley on wed 15 jan 03
A 6 to 8 inch thick slab is much thicker than you need.
A typical slab in Texas is about 4 inches thick, with
thicker "footings" around the perimeter.
Usual practice would be to make the footings about 8 to
10 inches deep and wide, and set some lightweight rebar
running along the trench.
The rest of the slab would be 4 inches thick, with wire
mesh running through the middle of it.
The rebar and mesh are held in place with plastic
"high-chairs", as the locals call them.
I hope you will build your shed roof and roof framing
structure out of metal, not wood. It is well worth the
small extra cost and trouble.
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
----- Original Message -----
> I am in the prepatory phase of building my kiln shed. I have looked
> at the cost over time of several sizes of slab and the construction
> involved and it looks like for me a slab of about 15' x 30' would
> provide space for dry materials, clay and two propane kilns.
>
> Does anyone know of the metal mesh or rebar or whatever could be used
> in a slab of 6" - 8" that would not have to accomodate any more
> weight than 1000 lbs per square foot?
>
> I hope that this is the forum for this kind of discussion.
"Steven D. Lee on wed 15 jan 03
I am in the prepatory phase of building my kiln shed. I have looked
at the cost over time of several sizes of slab and the construction
involved and it looks like for me a slab of about 15' x 30' would
provide space for dry materials, clay and two propane kilns.
I have read a lot of material on making concrete slabs but so much of
it is designed with a house or other very heavy structure in mind.
As I understand it, the typical kiln made of insulating brick will
only weigh in at about one fourth of a similar brick BBQ or the
equivalent.
Does anyone know of the metal mesh or rebar or whatever could be used
in a slab of 6" - 8" that would not have to accomodate any more
weight than 1000 lbs per square foot?
I hope that this is the forum for this kind of discussion.
*******************************************************
Steven D. Lee
SD Pottery - The Little Texas Pottery
http://www.sdpottery.com
millenial_age@yahoo.com
14341 FM 112
Thrall, TX 76578
512-898-5195
*******************************************************
Working Potter on thu 16 jan 03
my 45cuft gas kiln is a combination of hardbrick and soft in appropriate
places for outdoor use ad my kiln pad is built on an 8''base of compacted
sandy clayish base then a heavyduty plastic barrier then stainless tied
[wire]medium weight steel rebar [crossing up and down] propped on brick
chips or stones 1 1/2 '' high[so the rebar floats in the middle of the
concrete] then heavyweght 6''-8'' hogwire[square openings] over the
rebar,and pour the concrete is at least 4'' but closer to 5''[not totally
necessary the 5'',but check any codes as climate may dictate
differences].The concrete needs seperating breaks [I did them 4' increments]
this is to prevent later cracking, check your supplier for the best
seperators for your climate.Do not use accelertors in the concrete and ask
about what different mixes they carry and learn the best for your needs
.Have plenty of experienced help for a pour the size you plan and pay a
professional finisher to complete it and cover the finishe job with plastic
to slow cure it and some use hay or straw over the plastic to keep the sun
off.A slow cure is stronger and try to avoid a rain the first week,if
possible.A month is ideal to cure before you build.Do not build the kiln
directly on concrete as moisture in the cncrete will explode it when heated
by the firing.I like to line the concrete blocks up so circulation under the
kiln occurrs.A barrier between the cement block base is next[we used to use
transite[had asbestos] but concrete tile backer board is used by many
now.Now proceed with the kiln.I built my kiln using the shelf configuration
[size]as a starting point.I'm in a warmer climate so a sheet of transite or
corrigated metal suffices as the outside is hardbrick as is the chimney.
Misty
Jennifer F Boyer on thu 16 jan 03
I've told this tale of woe before, but others may benefit. I'm
in Vermont where things get a bit chilly in winter.
My first kiln(in a pole barn) was built on a 4-6 inch thick
"floating" slab with no footings. A friend was SURE it would
work. The site had been leveled with a bull dozer. After a few
years of firing this kiln I noticed that the burners(plumbing
attached to walls of pole barn) on one side kept getting closer
to the kiln as the ones on the other side got farther away...I
switched to a handy dandy flexible looped copper plumbing system
that would have made the gas company guy have a panic attack. It
allowed me to move the burners as needed.
The deal was that the ground was either not compacted enough or
had drainage problems and the slab that the kiln was on was
sinking on one side.
Solution: Dig under the two low corners, jack em up and build
footings out of stone under there...not a job I'm planning on
repeating any time soon.
Moral: get good advice about the slab from people in your area
who know what they're talking about....I'm assuming Texas has a
different set of climate/ground issues than VT but .....better
safe than sorry.
Jennifer in Vermont where we haven't been above 20 degrees for
awhile
Roger Korn wrote:
> I'd pour a 4" slab with 6" x 6" #9 wire mesh reinforcing, placed 1"
> from the bottom of the slab.
> Get a good flatwork person to supervise the pour and finish the slab -
> this is a skilled job. You'll be ordering about
> 6 yards of concrete, so figure about $400 for the concrete and about
> $100 for the reinforcing, plus about $150
> labor for the flatwork person. You can do the forming yourself - set 2 x
> 4s level with the top of the slab and
> stake on 16" center if you need a really straight edge.
>
> Hope this helps,
> Roger
>
> Steven D. Lee wrote:
>
>
--
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Jennifer Boyer mailto:jboyer@adelphia.net
Thistle Hill Pottery Montpelier VT USA
http://www.thistlehillpottery.com/
Never pass on an email warning without checking out these sites
for web hoaxes and junk:
http://urbanlegends.about.com/
http://snopes.com
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Roger Korn on thu 16 jan 03
I'd pour a 4" slab with 6" x 6" #9 wire mesh reinforcing, placed 1"
from the bottom of the slab.
Get a good flatwork person to supervise the pour and finish the slab -
this is a skilled job. You'll be ordering about
6 yards of concrete, so figure about $400 for the concrete and about
$100 for the reinforcing, plus about $150
labor for the flatwork person. You can do the forming yourself - set 2 x
4s level with the top of the slab and
stake on 16" center if you need a really straight edge.
Hope this helps,
Roger
Steven D. Lee wrote:
>I am in the prepatory phase of building my kiln shed. I have looked
>at the cost over time of several sizes of slab and the construction
>involved and it looks like for me a slab of about 15' x 30' would
>provide space for dry materials, clay and two propane kilns.
>
>I have read a lot of material on making concrete slabs but so much of
>it is designed with a house or other very heavy structure in mind.
>
>As I understand it, the typical kiln made of insulating brick will
>only weigh in at about one fourth of a similar brick BBQ or the
>equivalent.
>
>Does anyone know of the metal mesh or rebar or whatever could be used
>in a slab of 6" - 8" that would not have to accomodate any more
>weight than 1000 lbs per square foot?
>
>I hope that this is the forum for this kind of discussion.
>
>*******************************************************
>Steven D. Lee
>SD Pottery - The Little Texas Pottery
>http://www.sdpottery.com
>millenial_age@yahoo.com
>14341 FM 112
>Thrall, TX 76578
>512-898-5195
>*******************************************************
>
>______________________________________________________________________________
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>
--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
Dave Finkelnburg on thu 16 jan 03
Stephen,
I got this information from a professional engineer.
You can either use 6" x 6" remesh or 3/8-inch rebar on 18" centers for
reinforcement, placed a minimum of 2" below the surface of the slab, but
nearer the surface than the bottom.
He recommended that your slab, 6" minimum, be made from 4,000-PSI
concrete (unless you specify this you will get about 2,500-PSI), 4" slump
(not less), 5%+/- 1% air entrainment to prevent freeze-thaw damage.
For areas with frost in the ground, under the slab he recommended good
drainage, either 12-inches of pit run gravel or 6 to 8 inches of "flowable
fill." The latter is low quality concrete, ~1,000-PSI. In your case you
probably don't have any frost to worry about so you may be able to ignore
this part.
In any case, you should compact the fill or soil under the slab so it
provides uniform support for the slab.
Good luck!
Dave Finkelnburg
----- Original Message -----
From: "Steven D. Lee "
> I am in the prepatory phase of building my kiln shed. I have looked
> at the cost over time of several sizes of slab and the construction
> involved and it looks like for me a slab of about 15' x 30' would
> provide space for dry materials, clay and two propane kilns.
> Does anyone know of the metal mesh or rebar or whatever could be used
> in a slab of 6" - 8" that would not have to accomodate any more
> weight than 1000 lbs per square foot?
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