Insulation / Vermiculite

[sammy]

I just started building a brick oven. I have the foundation poured, the block stand built, and have just poured the insulating hearth. My issue is that I went to my local garden supply store and bought vermiculite, specifically asking about it not having silica and or asbestos and the individuals at the store said that there was none in the product. I was running late and took their word for it. Realizing this is my fault, but after I finally got home, I totally forgot to double check and I just finished mixing and pouring the insulating hearth when I was picking up the trash and I saw that the vermiculite did indeed have silica and asbestos in it I have a four year old and a two year old and am a cancer survivor myself (of 14 years now) and now I am kind of freaking out over the fact that I used stuff that possibly doesn't provide as good of insulating value plus potentially causes cancer and other health risks to myself and my family and friends. Do I need to tear this thing apart I didn't even know there were still legal uses of products with asbestos in it! Anyway, anyone have some tips on this for me???

[Unofornaio]

Re: Insulation / Vermiculite

I'm not an asbestos expert by any means but I'm fairly certain the dangers of asbestos fibers comes from them being airborne and then inhaled into your system. Every time I have encountered asbestos material myself or have seen or heard information regarding its dangers it has concentrated on the fibers being airborne. Your vermiculite mixture is now safely encased in a cement mixture and in that solid state I don't believe it will be an issue. Remember this is eventually going to be completely covered by the oven and its housing. The only place it may still be exposed is under the oven itself, if this gives you concern you could always "face" it with a cement sand mixture to seal it off. I'm really not sure of the bottom of the insulation temps of the pizza ovens but if its in the 100-200 degree area just a facing of sand and cement (like a whitewash mixture) painted on the bottom should do.
Again I am not an expert when it comes to asbestos.
Good luck.

[maver]

Re: Insulation / Vermiculite

I'm also not an asbestos expert per se, but I am a doctor who takes care of quite a few patients with past asbestos exposure. First of all, please try to determine what amount of exposure you have had - what did the label actually say? My understanding is that there was a vermiculite mine in Montana about 10 years ago that had asbestos contamination, but that you shouldn't see asbestos in quantities to pose substantial risk in currently available products.

If you were exposed, then that's not great, but the risk with asbestos exposure has to do with cumulative exposure. The risk is magnified greatly if you smoke. The classic medical example is WWII naval pipefitters, where asbestos exposure was a daily occurence. Also, automotive brake pads used to contain asbestos, as did some older popcorn ceiling sprays. Nevertheless a one day exposure is likely insignificant, especially if (as I would expect) the asbestos level in the vermiculite was very small.

Unofornaio is exactly right, once it is part of your insulating hearth, it is inert. We used asbestos hot pads all the time in college - as long as you don't take a file to it or in some other way form small aerosolized particles it is harmless. You don't need to seal the hearth in any special way, but when you finish the oven you want to cover the sides with something (it's just not pretty, you need something over it ).

The silica could be a concern if it is construction vermiculite treated with a sealant to repel water - but you'll know if that's a concern if 4 days after pouring it you still don't have it firming up to handle the vertical load. I bet yours will be fine, remember silica is a highly common soil component, the label is probably just reflecting that. Perhaps the label tells you to wear a mask when handling it. If you did, then you should have no concerns.

By the way, there are plenty of nasty components to firebrick as well, soak the bricks prior to cutting them, and you probably should wear a mask for that as well.

Marc

[james]

Re: Insulation / Vermiculite

Sammy,
Where do you live? All of the vermiculite I have found in California specifically says asbestos free on the packaging.

I am also not an expert on the topic and will defer to others who know more. I will however put a sticky posting in this category that covers safety issues.

James

[sammy]

Re: Insulation / Vermiculite

Thanks, gang. I had the same thought about the vermiculite/asbestos being contained in the cement. Still, it is a little annoying to know that places can still sell products that are not asbestos free. Anyway, I am in the midwest (IA). I think I may call my local EPA offices just to double check....and based on your feedback, I will also double check with Earl May to see what the deal is with the silica; but I feel a little better reading your feedback. I think I might also mention something to this Earl May store and their headquarters that they should consider using an asbestos free product, since it does exist and they charge a premium for the stuff anyway (a 4 cu ft bag costs about $9/bag at a store about an hour from here, but it was $20/bag at this store here in town).

[delay!fox]

Re: Insulation / Vermiculite

Maver, James... I have a similar nightmare story...

After I poured my hearth, I noticed that the the Bag of Vermiculite has the following information. I'm upset that I didn't notice prior to pouring.

BRAND:

A-TOPS Vermiculite Masonary Insulation
Water Repelant For Block & Cavity Walls

Need a little help here guys...

1) Did I screw up and use the wrong material?
2) Will the insulating Hearth function as designed?
3) Will this material HOLD or will it crumble?
3) There is no mention of Asbestos but bag does not to wear a mask
4) Will I need to REMOVE this layer and reapply? ((YIKES))
5) Does anyone have any other solutions?

[sammy]

Re: Insulation / Vermiculite

I was pretty pissed about the whole situation when I went through it and I definitely complained to the place where I purchased the stuff I got. That said, I called the local EPA offices and their point was that if it was set in concrete than asbestos particles would be tied up in the concrete and would not be "loosely blown". The other side of it is that it is outdoors and not in a confined environment (like a house) where you breath all types of dust in...day in and day out. So, if yours is outdoors in concrete than it probably isn't a big deal....if it is loose insulation indoors, than you might want to call your local EPA office and get their take on it.

[Les]

Re: Insulation / Vermiculite

I have had to buy vermiculite on three different occasions - they were all labeled asbestos free. Are they still selling asbestos in the USA? Also, the product is covered with mortar, brick, etc. At the end of the day, any exposure for the time you use the oven, is less than one home brake job in the 70's

Les...

[delay!fox]

Re: Insulation / Vermiculite

Sammy do you remember the brand that you used and was it labeled as containing Asbestos??

[delay!fox]

Re: Insulation / Vermiculite

Les.... seems like you know a thing or two...can you address the following for me?

After I poured my hearth, I noticed that the the Bag of Vermiculite has the following information. I'm upset that I didn't notice prior to pouring.

BRAND:

A-TOPS Vermiculite Masonary Insulation
Water Repelant For Block & Cavity Walls

Need a little help here guys...

1) Did I screw up and use the wrong material?
2) Will the insulating Hearth function as designed?
3) Will this material HOLD or will it crumble?
3) There is no mention of Asbestos but bag does not to wear a mask
4) Will I need to REMOVE this layer and reapply? ((YIKES))
5) Does anyone have any other solutions?

[dmun]

Re: Insulation / Vermiculite

No OEM could sell a product containing asbestos in the USA. Even if it were legal, the liability problems would (and have) destroy entire industries. Anyone been to Manville NJ recently?

Unless you bought 20 year old bags off the back of a truck, you have no worry about asbestos. You still don't want to breathe the loose dust: silica is no lung treat either...

I don't know the answer to the silicone treated water resistant stuff. I know it's not recommended. You may just have to wait to see if it hardens up.

[Les]

Re: Insulation / Vermiculite

Delay - I didn't use vermiculite for the floor base. I went with the board. I used mine for insulation over the blanket's and flue. I did notice that the first two bags had the shape of "cottage cheese", and the third bag looked like sawdust. All of them set pretty well after the 5/1 mix. I sat my last 7 courses of decorative brick on it and it's solid as hell. I think you are good to go. This project is very intimidating at the gate, follow the plans and it will be good. Build on....

Les...

[james]

Re: Insulation / Vermiculite

Hey delay!fox,

I have to echo what Dmun wrote (is that the second time today?). I would not worry about any current vermiculite product having asbestos. Further, it is contained within your Portland cement mix and enclosed inside your oven.

Most vermiculite concrete feels soft (like oatmeal) as it cures, but it eventually sets, and its only role in live is to act as a passive insulator. It will definitely have the compression strength to hold up your oven.

Let us know how it goes.
James