Is this asking for trouble?

First of all if I have posted in the wrong section can the mods please move it to the appropriate one.

This is where I am at.

I am wanting to build an earth oven. I finally got some concrete bricks for the base and have put them together to form it. I filled in the middle of it today.

There are 80 bricks which I am prety sure weigh 10kg each.

The dimensions are 127x120 cm by 73 cm high. The middle is filled with those standard garden rocks ( I think they are volcanic) and crushed rock (gravel). The whole thing sits on about 5cm of gravel. I dug out the 5cm and filled with gravel before building this on top. The ground is very hard clay.

On this will go about 4 inches of sand then the firebricks. I have used a level and it is fairly even all around.

The oven itself will be 66cm by about 45 cm high in an igloo type structure. 2 layers. The first will be 8cm mix of clay and sand and the second wil be 15cm, which will consist of clay sand and straw which I beleive is what a mud brick is made from. The oven will be heavy, but I do not know how heavy. I am guessing anywhere between 3-700kg. I have no idea a I have not tried working that out yet.

I have never built anything before and I am not vey handy. It has taken me a few weeks to get to this stage.

Will this do as it is or should I take it down and mortar it up, then build the oven on top?

My bro in law is a brickie and he could fix it up but the problem is getting him to our house.

Pic of where I am at.
http://img230.imageshack.us/img230/9073/basett8.th.jpg


Also a link to something similar. http://www.pequals.com/at/blueoxoven/oven_completed.jpg

ok ....several things I can think of, not ever have I built one myself ....but
I would have firstly made a concrete base for it to sit on , at least 300mm wider all round ....secondly ...I would have mortared the project ......the structure looks ok, but you have to think what happens when it rains?..all that weight in one spot will definately have an impact on the soil below .....you may end up with the worlds first leaning woodfire oven ....or even worse ....it may topple over ....great things are built on a solid foundation....and I think thats where you should start ......just my opinion :2tsup: