For experts and/or experienced builders!

[Onyxx]

Hi, this is my first post... so nice meeting you ALL!

My name is Gary, I was born in the US 40 years ago!! (S***!)? Anyway, I have been living in Argentina for the past 10 years.
I?ve recently started building my own brick oven (just finished the support structure). I have spent hours upon hours, for the past month, reading about constructing a brick oven, and if someone would ask me right now; what is the most important aspect about it?... my answer will be ?INSULATION?

So, from what I understood, there are MANY ways to insulate an oven; mud, sand, glass (bottles or broken), salt, fiber blankets (glass, ceramic, stone, etc.), vermiculite, perlite, air, a combo of all or some? so on and so forth.

This been said, my question is simple? according to the experts or people who have already built an oven (or many)?

WHAT IS THE BEST INSULATION for a brick oven?

[Nic The Landscaper]

Re: For experts and/or experienced builders!

Ceramic board is by far the best, followed by insulating ceramic bricks, vermiculite cement and perlite cement mixes. Glass, sand, and stone are NOT insulators.

[Onyxx]

Re: For experts and/or experienced builders!

Hi Nick TL,

Insulating ceramic bricks!?!?!?!?! WOW! first time I hear about them...i?ll research those.

Another question; would you use the same arrange and materials for the insulation of both the dome and the oven floor?

[Nic The Landscaper]

Re: For experts and/or experienced builders!

you could use any combination of the materials as long as you are using the correct material for the purpose. ie: ceramic insulating blanket is not good for under a floor because it has no compressive resistance, but ceramic board is good for this.

[GianniFocaccia]

Re: For experts and/or experienced builders!

A number of FB builders have placed under their oven floor a layer of vermiculite concrete (vermicrete) topped by 2" of cermaic board. Ceramic insulating blanket is considered the best initial dome insulation (hot face) followed by either vermicrete or loose vermiculite or perlite. The thickness of your dome insulation is a funtion of the thickness of your wallet.

[Mike D]

Re: For experts and/or experienced builders!

It's worth the money to insulate correctly (or going too far). But it might depend on the overall design of your oven.

Mike

[brickie in oz]

Re: For experts and/or experienced builders!

My thoughts after building a very uninsulated oven then knocking it doing and redoing it..

Insulate.
Insulate.
Insulate.
Insulate.
Insulate.

And then add more insulation.

Bricks, sand, glass, clay or dead cats are not insulation.

[Onyxx]

Re: For experts and/or experienced builders!

Thanks a lot guys for your replies!!!

Brickie in oz, I agree with you 100% about insulation!

I have not started building the actual oven yet, I?ve just finished the support structure. So I am at the ?data gathering stage?, if you will. This is why I decided to post a message in the forum so that I may gather valuable info on the matter from people that know what they are talking about such as you.

I was wondering what was the reason you had to tear your original oven down and start again...I would love to hear that story because it might have valuable data to learn from. Although I?m sure you are tired of telling it.

I have to say tho, I?m not so sure I agree with you about dead cats NOT being good insulation material. As I understand it, air is the best insulation there is, right?
So it is my opinion that the air in the cat?s fur will make great insulation from dead cats.
What I am not so sure about is if the best way to go here is with dead cats or live cats....hmmmm
I will perform some experiments on the subject and get back to you with the data.

P.S. Note to PETA members and animal lovers in general, I am ONLY kidding about this... I will not use dead cats for any experiments.

[RTflorida]

Re: For experts and/or experienced builders!

Onyxx, if you choose the cat route you will be competing with my neighbor for all of the strays out there. I swear, at least once a week she either is roasting cats on her grill or rotting garbage (I can't get close enought to see because of the smell)

RT

[Onyxx]

Re: For experts and/or experienced builders!

Sorry to hear that! I mean, I do not know what a roasting cat smells like but I do know what rotting garbage smells like and it is not a good experience at all!

Back to the insulation subject; I am having a HELL of a time finding vermiculite in the proper amount and also at a good price, at least not here in Rosario, Argentina.
I am able to find small bags of it at local plant nurseries (they use it for gardening I guess) but not in big bags like I need and the price for these small bags is not cheap at all if I have to buy 20+ bags of the stuff.
I was able to find through an eBay like website (MercadoLibre) a supplier of perlite instead and it is much cheaper than the vermiculite?
So my question is; how does perlite compare to vermiculite as an insulation material and can I go with the perlite without losing insulation properties?

I want to use vermicrete or prelicrete (?) for under the floor insulation. I am not sure yet if I will use it for the dome. Which brings me to my next question, I am able to find ceramic blankets but at higher then the sky prices so I decided right away that they are out of budget for my oven (and yes? the budget is handled by my wife?) so instead I will go with glass wool batts! I can get those at a reasonable price. My question; how much glass wool do I need to use (how thick) in order to get similar results to using ceramic blankets?

Thanks.

[splatgirl]

Re: For experts and/or experienced builders!

perlite or vermiculite are interchangeable in this case.

[brickie in oz]

Re: For experts and/or experienced builders!

I was wondering what was the reason you had to tear your original oven down and start again...I would love to hear that story because it might have valuable data to learn from. Although I?m sure you are tired of telling it.

Here is a thread about pulling down the old oven, it sort of explains things.

http://www.fornobravo.com/forum/f28/reverse-build-15263.html

.

[david s]

Re: For experts and/or experienced builders!

Perlite is a slightly better insulator than vermiculite, but the more cement you mix with it the more you reduce it's insulating value. For the under floor slab go with a 5:1 mix for enough strength to hold the weight.
Fiberglass insulating bats tend to compress way too much (compressing will reduce it's insulating capacity) and are difficult to work against if you are doing an igloo, they might be ok for an enclosure. Some people have reported that the binder burns away, but I used them on my first oven and when I finally pulled it apart the fiberglass was still in good condition with no sign of any burning.maybe mine was a different brand.

.

[david s]

Re: For experts and/or experienced builders!

In the absense of insulating board, blanket vermiculite or perlite, do not discount the broken glass method, it's been used for ages . It gets it's insulating value from the trapped air between the glass. A bucket full of broken glass, particularly if you use broken bottles with unsmashed necks and plenty of curved forms to create big spaces, is not particularly heavy and contains lots of good insulating air. A fiberglass bat is after all simply glass and air too.a thicker layer of a poorer insulator will give you the same result. Eg 1" insulating blanket=. 2" Vermicrete approx.

[Onyxx]

Re: For experts and/or experienced builders!

Hi david s... you know, when i started researching about brick ovens a couple of months ago here in Argentina (they are called Horno de Ladrillos here), there wasn?t a single website that didn?t mentioned the use of broken glass as an insulation material. So I thought, OK, that is easy to get so I?ll go with that, I even had in mind using some empty wine bottles I have kept from ?special? occasions? yes, I know, I`m a remantic fool.
But then I started finding more and more people against the use of it (without really explaining why tho) so I then decided not to use it.

So now that I know someone out there is not completely against it, let me ask you:

What would you pour on top of the broken glass?

If the air in between the glass is what we are looking for, wouldn?t be better to use the whole empty bottle?

Would you choose glass (broken or whole bottle?) for the oven floor insulation over glass wool?

What do you think about a bed of empty bottles laid down with perlite concrete poured on top of that?

I am very, VERY interested in your answer (and everyone?s answer) as I am about to start my oven floor this weekend (hopefully)?