Water in Oven

[dmazzott]

My pool contractor recently built me a free custom oven for a referral. Sounds good, but I have a few 'concerns' that are typically experienced when you have someone else do something (their way) that you planned to do yourself (the right way).

I explained to my contractor that I wanted a domed oven like the plans on this site show. But his stone crew dove right in and built a shallow barrel oven before he was able to get them the FB Pompeii plans I downloaded. We took down the barrel and built a boxed in, 36 inch dome with firebrick, rockwool insulation, and a stacked stone veneer. I am very happy with how it came out, but I don't have a strong sense that they took the time to closely follow the FB Pompeii build plans like I would have if I was building it. So I need to ease my mind of the following concerns:

First problem... they built the oven floor over a woodbox that was made out of concrete/cinder block. It is reinforced, so I think this is structurally sound.. but my concern is that the floor they laid for the barrel was not as insulated as the FB build instructions call for. When they rebuilt it as a dome, they laid a second layer of firebrick over top of the first to address this--- is this a sufficient insulator?

Second problem... when rebuilding the dome, they laid out the first few rows/layers of fire brick with pretty clean mortar seams, which are visible from the oven opening and look nice. But from about the 4th row and up, the mortar seems are not 'clean' because they filled it with sand and built from the outside around the sand form--- will this unseen 'sloppy mortar' issue have any bearing on heat retention/temperature quality or the circulation of heat around the dome?

Last but not least... after the dome was complete and set for a week, the sand was swept out. I let it sit for the past 3 or so weeks without anything burning in it. However, someone rinsed out the INSIDE of the oven this week with a hose using a pretty substantial amount of water. The question is... is this ok, or does this water present a MAJOR issue? Is allowing it to fully dry for an extended period sufficient enough before following the first cure/first week burn temp guidelines (if so, how long)? Does the fact that I have two layers of fire brick on the floor complicate this excess water issue?

Thanks for any advice/responses!

[deejayoh]

The water in the oven is a concern - and will take time to dry - but the biggest issue you will probably have with this oven is the lack of insulation under it. A second layer of firebrick is not an insulator unless the first is white insulating firebrick (IFB). More than likely it is regular firebrick, which is more mass to heat from your oven. So you have ~4.5 inches of mass under your oven and no insulation. It will take forever to get it hot. It may be ok for cooking pizza while you have a good fire going, but it will not stay hot for nearly as long as it should without insulation

You may be able to recover to some extent. Depends on whether they built the dome on or around the floor. If you can pull out the floor bricks, you can replace the bottom layer of brick with either CF board or IFB without raising the floor of your oven.

I'd take care of that (or have your contractor do it) before I started curing. It will be a lot less messy!