oven base and floor

[ls2671]

Hello, I'm building the 36" Pompeii oven and the primary use is for a cooking a couple pizza's and bread. I had a 5" concrete base poured ( not insulated, why I'm asking this question), a mix of sand fire clay and water underneath my 2.5" fire brick. This is already done and the dome is almost 90% complete. I'm putting a 1.5" FB Blanket and insulating concrete on the dome and then filling the enclosure with 6" of perlite. I could have sworn that I read you didn't need the 2" FB board unless you were cooking large amounts of bread or pizza's.Is this sufficient or will I lose too much heat?

[SCChris]

Re: oven base and floor

If at all possible, add some rigid insulation under the dome floor.. Any floor insulation that you can add will make your oven much more flexible with regard to your cooking and make your life using the oven, heating the oven, easier.. My opinion is that not using sub-floor insulation is really cheating yourself.

Chris

[boerwarrior]

Re: oven base and floor

ls2671

This is kind of like those situations when your spouse asks you a question and you need to figure out if it is a real question or if it is one of those questions that only has one correct answer!

If in your opinion you are past the point of no return and you are simply trying to find out if you will be OK without floor insulation then there is a good possibility that someone will respond and make you feel alright. There are some people on this forum who have built ovens without floor insulation but I cannot comment on how successful their ovens are.

If this is a real question and you want an honest answer then I would say that you definitely want and need floor insulation. I have a small oven (32") and I have 3 inches of CalSil board under my floor bricks and even for small dinners I am very thankful for the insulation. I think the majority of experienced contributors to this site would agree. If your dome is 90% complete there may be some creative ways you can still add the insulation without starting over. For instance, could you add insulation and a new firebrick floor on top of your existing floor? Just a suggestion.

Oh, one more thing - pictures are worth a thousands words - if you post some pictures you are more likely to get more responses. Good luck!

[SCChris]

Re: oven base and floor

If it were me and my oven and I could pull the floor and get any insulation under the floor, even a half inch, I'd do it. If you are beyond the point where this can be done, enjoy the oven and all of the great times the oven will allow you to enjoy..

Chris

[geisen]

Re: oven base and floor

Boerwarrior is wise.

Firebrick on top of concrete will not be as good as firebrick sitting on top of an insulating layer. Vermiculite mix is old school. modern insullation board is best. The cold concrete will act as a heat sink and suck the heat out of the firebricks. but i don't think you are going to notice a huge difference when cooking with an active fire. 900deg is going to force heat into the firebrick faster than the concrete will suck it out.

I am quite sure the original pompeii ovens did quite well without insullation board. Like all of us, you will just have to learn to cook with your oven. each one is different. you may not retain heat for as long after the fires go out, but bread cooks in a very short time.

Heck, it might be an advantage. I have 4inch slab of vermiculite mix and insullation board on top of that. i have two blankets on top of the dome. i retain heat so well i have to wait forever for my temps to drop enough to cook bread. You might be ready in half the time.

If you are beyond the point of adding an insulation layer easily, then don't worry. You just went waaaaaayyyy old school.....like Pompeii 79A.D.

[GIANLUCA]

Re: oven base and floor

My first oven I built without the knowledge of forno bravo forum the oven worked fine without knowing that it could have been better i had a 6" hearth and 2" bricks on top of that the floor did get warm but I never made anything else but pizza and I sold the house 5 months after I do know its still there and looks operationable here's the kicker would I do it again NO!! Way but sometimes not knowing I guess is better. My advise would be to lift out as many floor bricks as possible depending how you started your dome and put at least 1" ceramic board under it simple fix and it will help tremendously
Good luck

[ls2671]

Re: oven base and floor

Thanks for the feedback everyone. Unfortunately i am past that point of adding insulation under the flr. I just finished the chimney yesterday. I'll see what happens towards the end of next week when i start curing it. Thanks again!

[GIANLUCA]

Re: oven base and floor

Is your floor sitting inside or under the dome ? Why are you passed the point on no return. There are always options post more about your build there still may be hope

[ls2671]

Re: oven base and floor

The dome is on top of the flr. Not sure what i can do other than adding another layer on top right?

Here are a few pics.

[SCChris]

Re: oven base and floor

The dome is on top of the flr. Not sure what i can do other than adding another layer on top right?

Enjoy the oven and don't look back.



Chris

[Laurentius]

Re: oven base and floor

Hi Is,

You have a nice looking oven that will serve your stated functions. It will not do the things that you might want it to do, in the future because of the constant heat loss via the un-insulated base. It is, what it is. Many people here are on their 2nd to 5th build, maybe you will join that rank and file, if you get the bug. For now, cook something!

[GIANLUCA]

Re: oven base and floor

I thought maybe you would be able to remove the bricks that are not under the dome and fit the ceramic board then put another brick layer. But trust me my first oven I made the same mistake it worked fine!! Just didn't stay hot more than a few hours after the fire was removed. As others stated enjoy and move on