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insulation under kiln-wood floor-long

updated fri 31 jan 97


Pat Chesney on sat 18 jan 97

I tried to send this to the person, but the email address was missing.
Sorry you guys.

All you said sounds good. The advice in Sat. list is all good too. You can
cut down on the amount of bricks some if you follow his ideas. I am also
concerned with the weight load on a wooden structure. All wood floors are
not created equal.(I am also a hardwood floor contractor- my job to make
money to live on (:>) so I understand wood floors a little. ) You must
figure out the wight load and check the under structure-it could all come
down on you if you don't do this. It isn't hard to do-any good carpenter
can do it if you give him the weight per sq. ft.

For the absolute best and safest heat protection, you could do two things.

1. There are 2 boards at ceramic tile supply houses that they use to put
over floors to protect them from moisture and to give a surface for the
mortar to bond to. Check out Wonder Board or Hardy backer. Wonder Board
looks like cement and it is 3/4 inches thick. Hardy Backer is white and
about 1/4 thick. They are not expensive. Also, the Hardy Backer is great to
wedge on in the studio (this info just a freebe). They will reflect a lot
of heat and not transfer it through to the wood readily. They can be
screwed or nailed down if desired.

2. If you put galvanized metal sheets down on the wood or anywhere above
it, it will turn the heat radiation away from the surfaces under it. That
is the theory behind the aluminum foil between the walls of a kiln. Foil
will work for this also, but the sheet metal is tougher. You could layer
the floor with the boards, then foil or metal, then your concrete
blocks,etc. Any combination will work under the concrete blocks.

We have a large car kiln, which has a small gap around the car on the
bottom-we don't have excessive heat because of the air gap of the car
height even at cone 11. Air is an incredible insulator and heat transfer
medium. That is why the holes on the concrete blocks must line up to let
air through.

I would be sure to cover the wood floor with some material-at least plywood
or the concrete boards in a larger area than the kiln itself. There will be
many hot things around the kiln and if burners are outside the kiln at all,
it will be very hot around the combustion chambers. Wood will dry out with
heat and it will sometimes burst into flames with seemingly instantaneous

Good luck,

Pat Chesney
Waco, Texas