Treated Wood Base

[EricW]

Hello,

I completed a build of a Wood Fired Oven using Refractory cement, perlite and SS needles for the Dome and Fire Bricks, Refractory cement, perlite and cement patio tiles for the hearth. The oven is built on a Treated Lumber base with heavy duty castor's in case I wanted to relocate the oven. The actual oven itself is way too heavy to move and will likely stay on the base for the rest of it's existence.

I've used it many of times and it works great with one flaw. The base/hearth is compromised of 2" thick cement patio pavers, 2" of Refractory cement/perlite 10/1 volume mixture and 1 3/4" fire brick. Total is approx 5 3/4" thick base. The flaw is after a few hours of burning I noticed the treated lumber started heating up. I'm concerned over possible combustion, chemicals seeping from the wood etc. So far the wood got to about 155F but I fear as the wood dries more that number will rise.

Reason for the post: my thought process - since moving the oven off the base is not possible I wanted to figure a way to cover or insulate the wood.
I was thinking of using a fire retardant spray, covered by durock for the exposed wood underneath the ovens base.

I'm not certain if covering it and sealing it would cause more issues. (Addition heat on the wood etc.)

My goal is for safety and to ensure the integrity of the base.

Hopefully my thoughts are clear. I would really appreciate some input and direction.

Thank you in advance,

Eric

[david s]

My fear would be the chemicals used in the timber, if it was treated. Those chemicals are really nasty and should not be burned, 155 F may be enough to cause problems. Can you find out if the timber has been treated? Over time, particularly if left in the weather, your timber stand joints will begin to get some movement in them. You could cure this by adding some diagonals. As the under floor insulation dries it should perform much better, resulting in lower temps reaching the timber.

[EricW]

Thank you for the reply. The wood has been treated and I agree with the concern. I'm trying to figure out if covering the treated Wood with fire retardant spray and durock (cement board) would be a smart move.

[Toomulla]

you have not told us what chemical treatment was used on the timber, there are several. CCA treatment chemically locks the copper and chrome into the timber and may be released on decomposition of the timber, i.e. burning, your timber has not even reached the temperature of boiling water, and if it starts burning the CCA release is the least of your issues. enclosing itwith sheeting can only raise the temporary. Any top surfaces that may come in contact with food or your hands whilst cooking should be covered. I would not be concerned with the underside

[EricW]

Thank you for replying and the information.
I took this directly from the manufacturer site.

ProWood^®, the latest generation of pressure-treated wood. ... ProWood(MCA – Micronized Copper Azole) is pressure treated to protect against termite attack and decay.

[Gulf]

Eric,

You have about half the under floor insulation that is recommeded for a well funtioning oven. That being said, I don't think that you have any where near enough heat transferring to the wood to cause it to combust. From the one pic that I see, I think that you are absorbing moisture through the shell of the oven. Water moisture conducts heat and renders inulation ineffective.To go along with David S's thoughts, get it dry and keep it dry. I think that you will see a vast improvement.

[EricW]

Hi Joe,

I realized that I never said thank you for your response. (Better late than never)

Eric