42" Pompeii at the Concrete Casa

[michaewa]

I've been lurking / thinking for a while but finally got started in earnest on the oven this week. I poured a slab a while ago and got the stand finished yesterday.

You can see I had to taper the blocks as the slab had a lot of fall in it, but everything came out right. A good introduction to masonry for me.

I've got upright #4 rebars, two per side, and I'll bend these over into my bridge slab. One other thing I modified is the height of the lower opening, three blocks seemed too tight, so I'm just going to form the bridge slab to go over that opening.

I'm planning to do the bridge slab at about 4" of structural concrete, and then make a rectangular 'frame' out of 2" of structural concrete. In the middle of the frame underneath the oven floor I am planning to put the 2" insulating foam board I've seen mentioned here. Any thoughts / comments / suggestions on that approach are welcome.

Thanks for all the ideas and inspiration so far. Here are the obligatory block stand photos.

[DrakeRemoray]

Re: 42" Pompeii at the Concrete Casa

Looks like a great start? How are you planning to finish the oven? Igloo or enclosed. Glad to see you are thinking about insulation...very very important.

Also, great view!

Drake

[texassourdough]

Re: 42" Pompeii at the Concrete Casa

Looks like you have the blocks set nicely! One thing you might want to think about now, while it is easier... it appears your slab slopes down to the rear. you might want to use a hose to see where water collects and put a couple of drain holes in the appropriate places at the base/foundation interface.

Looks like it will be very convenient to the house. Mine is eight feet down and a bit far. You will enjoy the proximity!

Good Luck!
Jay

[michaewa]

Re: 42" Pompeii at the Concrete Casa

Thanks for the replies and suggestions.

I'm going to enclose the oven, using metal studs / concrete board / and some type of cladding - either stone veneer or maybe cement fiber board to match the house. It will have a simple roof with a ridge down the middle. The right side of the roof (looking at it from the front) will slope down a bit further over the edge of the slab, and on the right side of the structure I'm going to float a counter top to use as a prep surface.

I did think about the drainage, and just as you suggested I put a few weep holes in the bottom row while the mortar was still wet. I've yet to test it, but hopefully that will take care of most of the water issues.

I'm looking now for suppliers of the SuperIsol board, and it looks like Forno Bravo no longer sells it. Any suggestions on where to find it would be appreciated.

One additional question - I think I've read that ~150 firebricks is right for a 42" oven, does that sound about right?

[dmun]

Re: 42" Pompeii at the Concrete Casa

Superisol is a brand name for cal-sil board. Any refractory dealer will have some sort of insulation board, and the mineral fiber boards like insblock19 by Harbison-Walker will work fine, if you don't want to spring for the high price spread.

If you're building an enclosure around your oven, there's no particular reason to encase the edges of your board in concrete. One less step in the process, and mounds of concrete not to lift.

[papavino]

Re: 42" Pompeii at the Concrete Casa

One additional question - I think I've read that ~150 firebricks is right for a 42" oven, does that sound about right?

I went through about 175 for my 36". It depends on how low your dome is, how long your landing is, how efficient your cuts are, etc. I'm not saying 150 would be too few for a 42", but it would definitely be too few for the way that I build.

[cannyfradock]

Re: 42" Pompeii at the Concrete Casa

Hello Michaewa

Am new to FB forum and new to wood-oven building. Have just finnished mine and look forward to seeing your pics on how a wood-oven is proffesionaly built.

All the best with your project

Terry (C.F)

[Neil2]

Re: 42" Pompeii at the Concrete Casa

Here is a bit of discussion of the number of bricks needed:

http://www.fornobravo.com/forum/f2/h...-wfo-7680.html

[michaewa]

Re: 42" Pompeii at the Concrete Casa

Thanks for the reference Neil2 - I think I was setting myself up for two trips. Sounds like north of 200 is most likely, especially for a newbie mason like myself.

Thanks cannyfradock for the words of support but calling me a professional would be an insult to professionals everywhere I'm very much just winging it as I go, leaning on the experience of everyone here to get me by.

I've got the wood forms all set, now just need to add some additional steel and get some concrete out here, and I'll be ready to start slinging bricks.

[cannyfradock]

Re: 42" Pompeii at the Concrete Casa

michaewa

I have been following another thread of someone who is 2 or 3 stages ahead of you. He has also gone to great lenths to build a perfect base, but when he came to pour "the slab" his concrete was too dry ending up with the "old hats" on the forum, voicing their concern after seeing the voids in concrete pics after the shuttering was removed.

I am new to this forum, so was too late to comment on that project. When you pour YOUR slab, make sure the mix is not too dry nor too wet and after pouring make sure that you tap the shuttering many times with a small hammer so as to bring all the air bubbles to the surface and the "fat" reaches all extremities. This will also help with a good float/trowel finish to the top of your slab. You did'nt ask for this advice so I hope you don't mind me putting my twopenneth worth in.

Regards and best of luck with your project

Terry (C.F)

[michaewa]

Re: 42" Pompeii at the Concrete Casa

Terry - Thanks very much for the advice, that is a great point considering integrity problems with the slab could lead to much heartache down the road. This is (thankfully) one area that I have had a little more practice in (vs. none for the masonry!) - I contributed a lot of sweat equity to our driveway and the concrete floors in our house.

I've built some concrete counter tops as well, and a great way to get all the voids out (provided as you mentioned a proper mix consistency) is to run around the edges of the form with a palm sander. The vibration is not enough to cause problems with the forms, but it does a fantastic job of liquefying the concrete just enough to get a great finish.

I'll probably also throw some fiber into the slab mix as well, I have had great results with slabs as thin as 1" being quite strong with a healthy dose of glass or poly fibers.

Cheers!

[fxpose]

Re: 42" Pompeii at the Concrete Casa

I love that palm sander idea. I happen to have one but haven't really had use for it for many years.

[ThisOldGarageNJ]

Re: 42" Pompeii at the Concrete Casa

Hi Mich and welcome...

I have a 42 inch pompei I built and including the arch, 5 course chimney and floor I used 210 bricks...

Good luck with your build, looking good so far

Mark

[michaewa]

Re: 42" Pompeii at the Concrete Casa

Ok, it sounds like north of 200 is definitely where I need to be with firebricks. Thanks to all for your input.

I got the forms done and steel placed today, I decided to lay some plastic over the plywood as I invariably spend twice as long trying to pry the forms out as I do finishing the slab.

It appears that I will get lucky with concrete as well, my neighbor is pouring a sidewalk the day after tomorrow, and I'm going to tack on a yard to his order, which I think will be enough to fill all the cells and pour the slab. I was not looking forward to lugging all those bags of portland around.

Some additional standard photos:

[ThisOldGarageNJ]

Re: 42" Pompeii at the Concrete Casa

It appears that I will get lucky with concrete as well, my neighbor is pouring a sidewalk the day after tomorrow, and I'm going to tack on a yard to his order,

Now that is lucky,,, go out and buy some lottery tickets..

Nice so far,, looking good

Mark