Start of the Base

This past weekend we started building the base of the oven. Last night, after spending most of Saturday and  Sunday working, Scott and I evaluated the weekend. I was pleasantly surprised .. I thought we did a great job, I learned a lot about building a wall out of concrete block; I had low expectations. Scott was disappointed .. he felt it took us longer than he had expected; he had high expectations. Same result - different expectations, something we have learned to adjust during this project. It wasn't 'hard' work, but it was definitely a learning experience. A skill - not simple 'idiot work' like digging the hole for the slab.

Here is the final product ... our walls are straight, the box is a square, and when we kick it, it doesn't fallen over! At least yet.

Saturday morning started at 6:00am with our neighbor Todd driving his truck to Home Depot a couple trips to pick up block. Our truck is holding the oven, so we were without it. We needed 60 concrete blocks at 36 pounds a piece (2,160 pounds) and 5 bags of Quickcrete Mason mix at 80#'s per bag (400 pounds). No  task for our mini-van.

The next job was chalking the lines for the first row. That was our biggest struggle. How to get the box centered over our 'not so perfect' slab. Scott wouldn't want me saying how long it took, but let's just say it was equal to the value of the dollar bill that Abraham Lincoln's face adorns .. in hours. It is only fair to say we hosted my Aunt and Uncle during an hour of that time.

First row. The most difficult, as we struggled to get it square.

End of Day One .. Saturday night around 8:30pm. Yes, we started at 6:00am.

At the end of Saturday we started to panic about the height of the base, which in essence will give us the height of the hearth. We talked this through for hours in advance of this weekend, but when I saw how high three layers of block were, I thought our plan of five block would be too high. I started sending out emails, bombing the Brick Oven Yahoo group, and just plain thinking it through again and again. We decided to stick with the 48" height as planned. It was either 47", or 39" (4 or 5 rows of block) and we felt if it turned out to too high we could add a platform to the ground. Better than being too low and bending over all the time. 

As I mentioned before, we buried 2" PVC conduit in our slab, to use for electricity and water in the future. We must have spent an hour discussing this as well. Should we have it go through the middle of the block and up through the slab? Should it go outside the block? We concluded that we don't want it going through the slab, as it could get too hot and melt. So we brought one side through the block and back out so we could 'mount' an electric outlet to the outside of the wall down the road, and one side we left outside the block. I can't say we fully planned to have them different, we just forgot to put the one inside the brick as we were building the wall. And we aren't really sure which one will be better down the road, but at least now we are confident we will be 50% successful! 

PVC Conduit going through slab and up, outside the block.

PVC Conduit going through slab, up through block, and back out the

top row of block (covered with duct tape).

So overall here is what we did:

• On the two sides we laid 4 block, on the back we laid 3 1/2 block, and on the front we laid 1/2 a block, leaving a 24" opening for the wood storage and ash bucket (for only 3 rows).
• Final dimensions were 64" x 56".
We went 5 full rows up. We placed a 3" x 3" x 30" piece of angle iron above the front opening (front and back of the block) to continue our top two rows. Tip: If you live in the Twin Cities, you cannot buy this angle iron at your local hardware store (e.g., Home Depot). Saturday morning I had to drive to NE Minneapolis (Discount Steel">).
• We went through close to 60 8"x8"x16" block and 5 bags of Mason Mix (Quickcrete).
• The final height was 40 1/2". On top of this base we will put a 3 1/2" slab, 1" ceramic pad and 2 1/2" firebrick (total of 7"). That will bring our height to approximately 47". At least we hope.

Here is what I learned:

• The consistency of your Mason Mix is key. Too wet and the blocks sink. Too dry and you can't level them. The consistency is something you have to figure out on your own. I got it figured out just before I started row 4!
• Mandatory tools are gloves, a large trowel (16" ?), a small trowel (8" ?), a short level, a long 6' level, and lots of patience.

For fun, here is the video of me placing the last block. As you can tell from the video, and photos, it rained most of Sunday. We simply put up our canopy and worked under it. It actually made us look very professional, like we knew what we were doing. Don't be fooled. We didn't.