Started the Process - A couple of Questions

[George T]

Last weekend poured my pad 80 - 80lbs bags of concrete. for a Pizza Oven and fireplace unit.

This week I plan to get the block laid for the Oven stand and hopefully pour the concrete for the hearth. A few questions.

1. Has anyone ever just used treated plywood under the hearth and left it in place after the pour? I am thinking about putting in a course of block inside the wood storage area....which will make it difficult to remove the plywood and bracing....want to Keep the varmits out. I was also thinking to overlay it slighthly on the block. less need for all the bracing.

2. For the dome. Seems some are utilizing extensive fire brick cuts...e.g. Les. Is that requried for a good looking oven interior or durability. It seems tedious and is not what the instructions indicate. Just curious.

I will try to take some pictures to post as we progress.

[Les]

Re: Started the Process - A couple of Questions

If I understand your question #1 correctly you will have wood in between the hearth concrete and block. Probably not a good thing to do. In time the wood will rot and the hearth will want to go towards the center of the planet.

#2 is a slam - Les is insane. Many have build quality ovens without going through my pain. My reasoning is quite simple - I'm claustrophobic and didn't want to crawl in there to clean the joints.

Les...

[George T]

Re: Started the Process - A couple of Questions

Thanks Les. A couple thoughts. Pressure treated Plywood will last a long time.....15-20 years if not exposed to sunlight, ground, water, etc; I was thinking only overlapping a small amount so once the concrete is set up it wont go anywhere....even if it did rot.

PS. I love your dome! It just was scaring me.....I was starting to think I should build a barrel vault.

[dmun]

Re: Started the Process - A couple of Questions

I think the members who brag the most about their builds are the ones, like myself, who go to some extremes. Particularly if you use good refractory mortar, the standard half-brick dome works just fine.

If you want to leave your support material under your slab, think about a masonry product like wonderboard.

[james]

Re: Started the Process - A couple of Questions

Welcome aboard George,

I used Hardibacker, rather than pressure treated wood, and left the bottom form in place after the pour. I would recommend that over pressure treated plywood for two reasons -- first, the wood will eventually rot, and that won't be fun at the top of your wood storage area. Also, pressure treated wood used cyanide as the preservative, something you don't want exposed near you pizza. :-(.

On the barrel vault, just say no.

On Les, he's just very, very tidy. We all know someone like that -- you might even be married to someone like that. :-)

James

[George T]

Re: Started the Process - A couple of Questions

Thanks....I think I will do the masonry board concept. Another quick question....If I am laying block with Mortar joints for the stand and I appropriately re-enforce the concrete, is there any reason you really need the block on angle iron over the wood storage opening. The concrete can surely carry that small opening cant it?

[james]

Re: Started the Process - A couple of Questions

If I am laying block with Mortar joints for the stand and I appropriately re-enforce the concrete, is there any reason you really need the block on angle iron over the wood storage opening. The concrete can surely carry that small opening cant it?

Yep. Make sure your pad is thick enough and has enough rebar. I did my last oven that way.
James

[Les]

Re: Started the Process - A couple of Questions

Add the angle iron - the cost and work is insignificant to the whole project. Once you start moving the product onto your hearth - you have no idea how much weight this thing requires. I would error on the side of caution.

In regard to the wood against concrete - the yahoo's that built our development, placed the redwood posts inside of our concrete retaining walls (I'm on a slope), didn't take long for them to rot and everyones fences started to blow over. Just one of life's lessons that I will never repeat. Just my 2 cents.

Les...

[SpringJim]

Re: Started the Process - A couple of Questions

don't sweat the inside of the oven look....Les has an awesome dome but looks really don't count when you get to cooking. (they count to the builder and photographer). I have seen some very rough oven domes! The smoother the better for good circulation without friction but to go to the extent that Les did is not necessary for the average oven.

Again, Love your dome and pic's Les....that last brick from dome to chimney throat arch was fantastic...get's my vote for BOMJune

XJ

[Frances]

Re: Started the Process - A couple of Questions

Hi George T,

I had exactly the same questions as you starting out... my oven still has the wood support under the hearth - I figured it would stay dry under there anyway. And I put extra rebar over the entrance to the hearth instead of an angle iron, too. And I made as few cuts as possible, like in the plans... if you look around you will see plenty of ovens like that.

If every oven had to end up looking as perfect as like Les', we wouldn't have any new ovens at all....

[George T]

Re: Started the Process - A couple of Questions

Thanks for all the help.....regarding the hearth. I am assuming you pour the concrete first and then the insulating slab. Is it hard to get the vermiculite portland mixture smooth enough for the fire brick to sit on?

If you order the FB board how long does it take to get?

Also I have a tile saw with a 7.5 inch blade. Will that cut the firebrick? Or do you need a 10"?

Tomorrow we build the stand.

[RTflorida]

Re: Started the Process - A couple of Questions

George, I did not find the vermiculete difficult to work with...even hardened the heavy grained, high clumps were easy to scrape away. I confess to using a wetter slurry coat of heatstop mortar to smooth it out a bit further, don't know if it help much...all in all my hearth bricks came out pretty flat; I think my biggest problem was the size/shape variance of my firebrick (wire cut) - no two bricks were the exact same size.

As for the saw, go for the 10", it will cut through firebrick in one pass; with the 7.5" you will have to flip your bricks over to finish your cuts. The 10" saw from Harbor Freight is a verry reasonably priced workhorse for this task. I got mine just over a year ago on sale for $199 plus $29 for the blade...it works like a champ. Not sure of today's price - may be $229-$249 if not on sale.

RT

[PizzaJNKY]

Re: Started the Process - A couple of Questions

George, the insulating slab goes on top of the structural slab. I made my insulating slab with portland cement and perlite instead of vermiculite, but my guess is they are very similar to work with. I wouldn't worry too much about getting it smooth, I think level is more important. As for the FB boards, mine were delivered within two days of ordering them.

For the tile saw, I concur with RT Florida. The 10" Harbor Freight saw is hard to beat. I bought mine two months ago for $199.

[DrakeRemoray]

Re: Started the Process - A couple of Questions

I used a 7" saw it can be done...If I had to do it again I would get the 10"...makes life much easier.

[Frances]

Re: Started the Process - A couple of Questions

I actually got quite attached to my 7" angle grinder during the build... made it all a bit more of callenge